srings_1.miz



    begin

    reserve X for set;

    reserve S for Subset-Family of X;

    theorem :: SRINGS_1:1

    

     Lem1: for X,Y be set holds ((X \/ Y) \ (Y \ X)) = X

    proof

      let X,Y be set;

      

       A3: (X \/ (X /\ Y)) = X by XBOOLE_1: 22;

      

       A4: (X \ (Y \ X)) = ((X \ Y) \/ (X /\ X)) by XBOOLE_1: 52

      .= X by XBOOLE_1: 7, XBOOLE_1: 8;

      (Y \ (Y \ X)) = ((Y \ Y) \/ (Y /\ X)) by XBOOLE_1: 52

      .= ( {} \/ (Y /\ X)) by XBOOLE_1: 37

      .= (X /\ Y);

      hence thesis by XBOOLE_1: 42, A3, A4;

    end;

    registration

      let X, S;

      let S1,S2 be finite Subset of S;

      cluster ( INTERSECTION (S1,S2)) -> finite;

      coherence

      proof

        S1 is finite Subset-Family of X & S2 is finite Subset-Family of X by XBOOLE_1: 1;

        then ( card ( INTERSECTION (S1,S2))) c= ( card [:S1, S2:]) by TOPGEN_4: 25;

        hence thesis;

      end;

    end

    theorem :: SRINGS_1:2

    

     ThmVAL1: for S be Subset-Family of X, A be Element of S holds { x where x be Element of S : x in ( union (( PARTITIONS A) /\ ( Fin S))) } = ( union (( PARTITIONS A) /\ ( Fin S)))

    proof

      let S be Subset-Family of X, A be Element of S;

      thus { x where x be Element of S : x in ( union (( PARTITIONS A) /\ ( Fin S))) } c= ( union (( PARTITIONS A) /\ ( Fin S)))

      proof

        let u be object;

        assume u in { x where x be Element of S : x in ( union (( PARTITIONS A) /\ ( Fin S))) };

        then ex x be Element of S st u = x & x in ( union (( PARTITIONS A) /\ ( Fin S)));

        hence thesis;

      end;

      let u be object;

      assume

       A5A: u in ( union (( PARTITIONS A) /\ ( Fin S)));

      then

      consider v be set such that

       A6: u in v and

       A7: v in (( PARTITIONS A) /\ ( Fin S)) by TARSKI:def 4;

      v in ( Fin S) by A7, XBOOLE_0:def 4;

      then v c= S by FINSUB_1:def 5;

      hence thesis by A5A, A6;

    end;

    

     A4bis: ( PARTITIONS {} ) = { {} }

    proof

      thus ( PARTITIONS {} ) c= { {} }

      proof

        let x be object;

        assume x in ( PARTITIONS {} );

        then x is a_partition of {} by PARTIT1:def 3;

        then x = {} ;

        hence thesis by TARSKI:def 1;

      end;

      let x be object;

       {} in ( PARTITIONS {} ) by EQREL_1: 45, PARTIT1:def 3;

      hence thesis by TARSKI:def 1;

    end;

    registration

      let X, S;

      cluster ( union (( PARTITIONS {} ) /\ ( Fin S))) -> empty;

      coherence

      proof

        ( { {} } /\ ( Fin S)) = { {} }

        proof

          thus ( { {} } /\ ( Fin S)) c= { {} } by XBOOLE_1: 17;

           { {} } c= ( Fin S)

          proof

            let x be object;

            assume x in { {} };

            then

             J1: x = {} by TARSKI:def 1;

             {} c= S & {} is finite by XBOOLE_1: 2;

            hence thesis by J1, FINSUB_1:def 5;

          end;

          hence thesis by XBOOLE_1: 19;

        end;

        hence thesis by A4bis;

      end;

    end

    registration

      let X;

      cluster ( cobool X) -> with_empty_element;

      coherence

      proof

         {} in ( cobool X) by TARSKI:def 2;

        hence thesis;

      end;

    end

    

     Lem3: for S be Subset-Family of X st (for A,B be Element of S st (A \ B) is non empty holds ex P be finite Subset of S st P is a_partition of (A \ B)) holds (for A,B be Element of S holds ex P be finite Subset of S st P is a_partition of (A \ B))

    proof

      let S be Subset-Family of X;

      assume

       A1: for A,B be Element of S st (A \ B) is non empty holds ex P be finite Subset of S st P is a_partition of (A \ B);

      let S1,S2 be Element of S;

      per cases ;

        suppose

         A2: (S1 \ S2) is empty;

         {} is finite Subset of S & {} is a_partition of {} by SUBSET_1: 1, EQREL_1: 45;

        hence thesis by A2;

      end;

        suppose (S1 \ S2) is non empty;

        hence thesis by A1;

      end;

    end;

    

     Lem4: (for A,B be Element of ( cobool X) st (A /\ B) is non empty holds ex P be finite Subset of ( cobool X) st P is a_partition of (A /\ B)) & (for A,B be Element of ( cobool X) st B c= A holds ex P be finite Subset of ( cobool X) st P is a_partition of (A \ B)) & (for A,B be Element of ( cobool X) st (A \ B) is non empty holds ex P be finite Subset of ( cobool X) st P is a_partition of (A \ B)) & {X} is countable Subset of ( cobool X) & ( union {X}) = X

    proof

      set S = ( cobool X);

      

       A2: ex y be finite Subset of S st y is a_partition of X

      proof

        per cases ;

          suppose X is non empty;

          then

           A3: {X} is a_partition of X by EQREL_1: 39;

           {X} is finite Subset of S by ZFMISC_1: 7;

          hence thesis by A3;

        end;

          suppose

           A4: X is empty;

           {} is finite Subset of { {} , {} } by SUBSET_1: 1;

          hence thesis by EQREL_1: 45, A4;

        end;

      end;

      thus for A,B be Element of S st (A /\ B) is non empty holds ex P be finite Subset of S st P is a_partition of (A /\ B)

      proof

        let S1,S2 be Element of S;

        

         A7: S1 = {} or S1 = X by TARSKI:def 2;

        S2 = {} or S2 = X by TARSKI:def 2;

        hence thesis by A2, A7;

      end;

      for S1,S2 be Element of S st (S1 \ S2) is non empty holds ex P be finite Subset of S st P is a_partition of (S1 \ S2)

      proof

        let S1,S2 be Element of S;

        

         A10: S1 = {} or S1 = X by TARSKI:def 2;

        S2 = {} or S2 = X by TARSKI:def 2;

        hence thesis by A2, A10, XBOOLE_1: 37;

      end;

      hence thesis by ZFMISC_1: 7, Lem3;

    end;

    

     Lem5: for A,B be Element of S, p be finite Subset of S st B <> {} & B c= A & p is a_partition of (A \ B) holds ( {B} \/ p) is a_partition of A

    proof

      let A,B be Element of S;

      let p be finite Subset of S;

      assume

       A1: B <> {} ;

      assume

       A2: B c= A;

      assume

       A3: p is a_partition of (A \ B);

      

       A4: ( {B} \/ p) is Subset-Family of A

      proof

        

         A5: p c= ( bool A)

        proof

          ( bool (A \ B)) c= ( bool A) by ZFMISC_1: 67;

          hence thesis by A3, XBOOLE_1: 1;

        end;

         {B} c= ( bool A)

        proof

          

           A6: {B} c= ( bool B) by ZFMISC_1: 68;

          ( bool B) c= ( bool A) by A2, ZFMISC_1: 67;

          hence thesis by A6, XBOOLE_1: 1;

        end;

        hence thesis by A5, XBOOLE_1: 8;

      end;

      

       A7: ( union ( {B} \/ p)) = A

      proof

        ( union ( {B} \/ p)) = (( union {B}) \/ ( union p)) by ZFMISC_1: 78

        .= (B \/ (A \ B)) by A3, EQREL_1:def 4

        .= (A \/ B) by XBOOLE_1: 39;

        hence thesis by A2, XBOOLE_1: 12;

      end;

      for a be Subset of A st a in ( {B} \/ p) holds a <> {} & for b be Subset of A st b in ( {B} \/ p) holds a = b or a misses b

      proof

        let a be Subset of A;

        assume

         A8: a in ( {B} \/ p);

        then

         A9: a in {B} or a in p by XBOOLE_0:def 3;

        thus a <> {} by A1, A3, A8;

        thus for b be Subset of A st b in ( {B} \/ p) holds a = b or a misses b

        proof

          let b be Subset of A;

          assume b in ( {B} \/ p);

          then b in {B} or b in p by XBOOLE_0:def 3;

          then

           A10: (a = B & b = B) or (a = B & b in p) or (a in p & b = B) or (a in p & b in p) by A9, TARSKI:def 1;

          

           A11: a = B & b in p implies a misses b

          proof

            assume

             A12: a = B & b in p;

            (A \ B) misses B by XBOOLE_1: 85;

            hence thesis by A3, A12, XBOOLE_1: 63;

          end;

          a in p & b = B implies a misses b

          proof

            assume

             A14: a in p & b = B;

            (A \ B) misses B by XBOOLE_1: 85;

            hence thesis by A3, A14, XBOOLE_1: 63;

          end;

          hence thesis by A3, A10, A11, EQREL_1:def 4;

        end;

      end;

      hence thesis by A4, A7, EQREL_1:def 4;

    end;

    theorem :: SRINGS_1:3

    

     thmIL: for X be set st X is cap-closed cup-closed holds X is Ring_of_sets

    proof

      let X be set;

      assume X is cap-closed cup-closed;

      then for x,y be set st x in X & y in X holds (x /\ y) in X & (x \/ y) in X;

      hence thesis by COHSP_1:def 7, LATTICE7:def 8;

    end;

    begin

    

     Lem6: for S be non empty Subset-Family of X st (for A,B be Element of S holds ex P be finite Subset of S st P is a_partition of (A /\ B)) & (for C,D be Element of S st D c= C holds ex P be finite Subset of S st P is a_partition of (C \ D)) holds (for A be Element of S, Q be finite Subset of S st A is non empty & ( union Q) c= A & Q is a_partition of ( union Q) holds ex R be finite Subset of S st ( union R) misses ( union Q) & (Q \/ R) is a_partition of A)

    proof

      let S be non empty Subset-Family of X;

      assume

       A1: for A,B be Element of S holds ex P be finite Subset of S st P is a_partition of (A /\ B);

      assume

       A2: for C,D be Element of S st D c= C holds ex P be finite Subset of S st P is a_partition of (C \ D);

      let A be Element of S;

      let Q be finite Subset of S;

      assume that

       A3: A is non empty and

       A4: ( union Q) c= A and

       A5: Q is a_partition of ( union Q);

      consider qq be FinSequence such that

       A6: Q = ( rng qq) by FINSEQ_1: 52;

      

       A7: for i be set st i in ( dom qq) holds (qq . i) <> {}

      proof

        let i be set;

        assume i in ( dom qq);

        then (qq . i) in Q by A6, FUNCT_1:def 3;

        hence thesis by A5;

      end;

      per cases ;

        suppose

         A8: qq = {} ;

        then

         A9: Q = {} by A6;

        

         A10: {A} is finite Subset of S by SUBSET_1: 33;

        

         A11: {A} is a_partition of A by A3, EQREL_1: 39;

        

         A12: ( union {A}) misses ( union Q)

        proof

          ( union Q) = {} by A8, A6, ZFMISC_1: 2;

          hence thesis;

        end;

        ( {} \/ {A}) = {A};

        hence thesis by A9, A10, A11, A12;

      end;

        suppose

         A13: qq <> {} ;

        defpred P[ Nat] means for n be Nat st $1 = n & 1 <= n & n <= ( len qq) holds ex R be finite Subset of S st ( union R) misses ( union ( rng (qq | ( Seg n)))) & (( rng (qq | ( Seg n))) \/ R) is a_partition of A;

        

         A14: P[1]

        proof

          let n be Nat;

          assume

           A15: n = 1 & 1 <= n & n <= ( len qq);

          

           A16: 1 in ( Seg ( len qq)) by A15;

          then

           A17: 1 in ( dom qq) by FINSEQ_1:def 3;

          then

           A18: ( rng (qq | ( Seg 1))) = {(qq . 1)} by FINSEQ_1: 2, FUNCT_1: 98;

          

           A19: (qq . 1) c= A

          proof

            (qq . 1) in Q by A6, A17, FUNCT_1:def 3;

            then (qq . 1) c= ( union Q) by ZFMISC_1: 74;

            hence thesis by A4, XBOOLE_1: 1;

          end;

          

           A20: (qq . 1) is Element of S

          proof

            1 in ( dom qq) by A16, FINSEQ_1:def 3;

            then (qq . 1) in ( rng qq) by FUNCT_1:def 3;

            hence thesis by A6;

          end;

          then

          consider PP be finite Subset of S such that

           A21: PP is a_partition of (A \ (qq . 1)) by A2, A19;

          

           A21a: ( union PP) misses (qq . 1)

          proof

            ( union PP) = (A \ (qq . 1)) by A21, EQREL_1:def 4;

            hence thesis by XBOOLE_1: 79;

          end;

          ( {(qq . 1)} \/ PP) is a_partition of A by A17, A7, A19, A20, A21, Lem5;

          hence thesis by A15, A18, A21a;

        end;

        

         A23: for j be Nat st 1 <= j holds P[j] implies P[(j + 1)]

        proof

          let j be Nat;

          assume that

           A24: 1 <= j and

           A25: P[j];

          for n be Nat st (j + 1) = n & 1 <= n & n <= ( len qq) holds ex R be finite Subset of S st ( union R) misses ( union ( rng (qq | ( Seg n)))) & (( rng (qq | ( Seg n))) \/ R) is a_partition of A

          proof

            let n be Nat;

            assume that

             A26: (j + 1) = n and

             A27: 1 <= n and

             A28: n <= ( len qq);

            per cases ;

              suppose j <= ( len qq);

              then

              consider R1 be finite Subset of S such that

               A29: ( union R1) misses ( union ( rng (qq | ( Seg j)))) and

               A30: (( rng (qq | ( Seg j))) \/ R1) is a_partition of A by A24, A25;

              

               A31: n in ( Seg ( len qq)) by A27, A28;

              then

               A32: (j + 1) in ( dom qq) by A26, FINSEQ_1:def 3;

              ( Seg (j + 1)) = (( Seg j) \/ {(j + 1)}) by FINSEQ_1: 9;

              then (qq | ( Seg (j + 1))) = ((qq | ( Seg j)) \/ (qq | {(j + 1)})) by RELAT_1: 78;

              then

               A33: ( rng (qq | ( Seg (j + 1)))) = (( rng (qq | ( Seg j))) \/ ( rng (qq | {(j + 1)}))) by RELAT_1: 12;

              then

               A34: ( rng (qq | ( Seg (j + 1)))) = (( rng (qq | ( Seg j))) \/ {(qq . (j + 1))}) by A32, FUNCT_1: 98;

              per cases ;

                suppose (qq . (j + 1)) in ( rng (qq | ( Seg j)));

                then (( rng (qq | ( Seg j))) \/ {(qq . (j + 1))}) = ( rng (qq | ( Seg j))) by ZFMISC_1: 31, XBOOLE_1: 12;

                then ( rng (qq | ( Seg (j + 1)))) = ( rng (qq | ( Seg j))) by A33, A32, FUNCT_1: 98;

                hence thesis by A26, A29, A30;

              end;

                suppose

                 A35: not (qq . (j + 1)) in ( rng (qq | ( Seg j)));

                

                 A36: (qq . (j + 1)) misses ( union ( rng (qq | ( Seg j))))

                proof

                  assume not ((qq . (j + 1)) /\ ( union ( rng (qq | ( Seg j))))) = {} ;

                  then

                  consider x0 be object such that

                   A37: x0 in ((qq . (j + 1)) /\ ( union ( rng (qq | ( Seg j))))) by XBOOLE_0:def 1;

                  x0 in (qq . (j + 1)) & x0 in ( Union (qq | ( Seg j))) by A37, XBOOLE_0:def 4;

                  then

                  consider y0 be set such that

                   A38: x0 in y0 & y0 in ( rng (qq | ( Seg j))) by TARSKI:def 4;

                  consider j0 be object such that

                   A39: j0 in ( dom (qq | ( Seg j))) and

                   A40: y0 = ((qq | ( Seg j)) . j0) by A38, FUNCT_1:def 3;

                  x0 in (qq . j0) & x0 in (qq . (j + 1)) by A37, XBOOLE_0:def 4, A38, A40, A39, FUNCT_1: 47;

                  then

                   A41: x0 in ((qq . j0) /\ (qq . (j + 1))) by XBOOLE_0:def 4;

                  ( dom (qq | ( Seg j))) c= ( dom qq) by RELAT_1: 60;

                  then j0 in ( dom qq) & (j + 1) in ( dom qq) by A39, A31, A26, FINSEQ_1:def 3;

                  then (qq . j0) in Q & (qq . (j + 1)) in Q by A6, FUNCT_1:def 3;

                  then (qq . j0) = (qq . (j + 1)) by A5, A41, XBOOLE_0:def 7, EQREL_1:def 4;

                  hence thesis by A35, A38, A40, A39, FUNCT_1: 47;

                end;

                

                 A42: (qq . (j + 1)) in Q by A32, A6, FUNCT_1:def 3;

                then

                 A43: (qq . (j + 1)) c= ( union Q) by ZFMISC_1: 74;

                then

                 A44: (qq . (j + 1)) c= A by A4, XBOOLE_1: 1;

                consider RA be finite Subset of S such that

                 A45: RA is a_partition of (A \ (qq . (j + 1))) by A42, A43, A4, XBOOLE_1: 1, A2;

                

                 A46: for x be set st x in [:R1, RA:] holds ex x1,x2 be set, px be finite Subset of S st x = [x1, x2] & x1 in R1 & x2 in RA & px is a_partition of (x1 /\ x2)

                proof

                  let x be set;

                  assume x in [:R1, RA:];

                  then

                  consider x1,x2 be object such that

                   A47: x1 in R1 & x2 in RA & x = [x1, x2] by ZFMISC_1:def 2;

                  reconsider x1, x2 as set by TARSKI: 1;

                  consider px be finite Subset of S such that

                   A48: px is a_partition of (x1 /\ x2) by A47, A1;

                  thus thesis by A47, A48;

                end;

                defpred H[ object, object] means $1 in [:R1, RA:] & ex x1,x2 be set, px be finite Subset of S st $1 = [x1, x2] & x1 in R1 & x2 in RA & $2 = px & $2 is a_partition of (x1 /\ x2);

                set XA = the set of all x where x be finite Subset of S;

                

                 A49: for x be object st x in [:R1, RA:] holds ex y be object st y in XA & H[x, y]

                proof

                  let x be object;

                  assume

                   A50: x in [:R1, RA:];

                  then

                  consider x1,x2 be set, px be finite Subset of S such that

                   A51: x = [x1, x2] and

                   A52: x1 in R1 & x2 in RA and

                   A53: px is a_partition of (x1 /\ x2) by A46;

                  px in XA;

                  hence thesis by A50, A51, A52, A53;

                end;

                consider h be Function such that

                 A55: ( dom h) = [:R1, RA:] & ( rng h) c= XA and

                 A56: for x be object st x in [:R1, RA:] holds H[x, (h . x)] from FUNCT_1:sch 6( A49);

                

                 A57: ( Union h) is finite

                proof

                  for x be set st x in ( rng h) holds x is finite

                  proof

                    let x be set;

                    assume x in ( rng h);

                    then

                    consider x0 be object such that

                     A58: x0 in ( dom h) and

                     A59: x = (h . x0) by FUNCT_1:def 3;

                    consider x1,x2 be set, px be finite Subset of S such that x0 = [x1, x2] and x1 in R1 & x2 in RA and

                     A60: x = px and x is a_partition of (x1 /\ x2) by A58, A59, A55, A56;

                    thus thesis by A60;

                  end;

                  hence thesis by A55, FINSET_1: 7, FINSET_1: 8;

                end;

                

                 A61: ( rng h) c= ( bool S)

                proof

                  let x be object;

                  assume x in ( rng h);

                  then

                  consider x0 be object such that

                   A62: x0 in ( dom h) and

                   A63: x = (h . x0) by FUNCT_1:def 3;

                  consider x1,x2 be set, px be finite Subset of S such that x0 = [x1, x2] and x1 in R1 & x2 in RA and

                   A64: x = px and x is a_partition of (x1 /\ x2) by A62, A63, A55, A56;

                  thus thesis by A64;

                end;

                

                 A65: ( Union h) c= S

                proof

                  let x be object;

                  assume x in ( Union h);

                  then ex x0 be set st x in x0 & x0 in ( rng h) by TARSKI:def 4;

                  hence thesis by A61;

                end;

                

                 A68: ( union ( Union h)) misses ( union ( rng (qq | ( Seg n))))

                proof

                  (( union ( Union h)) /\ ( union ( rng (qq | ( Seg (j + 1)))))) c= {}

                  proof

                    let x be object;

                    assume x in (( union ( Union h)) /\ ( union ( rng (qq | ( Seg (j + 1))))));

                    then

                     A69: x in ( union ( Union h)) & x in ( union ( rng (qq | ( Seg (j + 1))))) by XBOOLE_0:def 4;

                    then

                    consider x0 be set such that

                     A70: x in x0 and

                     A71: x0 in ( Union h) by TARSKI:def 4;

                    consider x1 be set such that

                     A72: x in x1 and

                     A73: x1 in ( rng (qq | ( Seg (j + 1)))) by A69, TARSKI:def 4;

                    (x0 /\ x1) = {}

                    proof

                      (x0 /\ x1) c= {}

                      proof

                        let u be object;

                        assume

                         A74: u in (x0 /\ x1);

                        then

                         A75: u in x0 & u in x1 by XBOOLE_0:def 4;

                        consider x0a be set such that

                         A76: x0 in x0a and

                         A77: x0a in ( rng h) by A71, TARSKI:def 4;

                        consider t be object such that

                         A78: t in ( dom h) and

                         A79: (h . t) = x0a by A77, FUNCT_1:def 3;

                        consider ax1,ax2 be set, apx be finite Subset of S such that t = [ax1, ax2] and

                         A80: ax1 in R1 & ax2 in RA and

                         A81: x0a = apx and

                         A82: x0a is a_partition of (ax1 /\ ax2) by A78, A79, A55, A56;

                        

                         A83: u in x0 & x0 in apx by A74, XBOOLE_0:def 4, A76, A81;

                        u in ax1 & ax1 in R1 by A83, A82, A81, A80, XBOOLE_0:def 4;

                        then u in ( union R1) by TARSKI:def 4;

                        then

                         A85: not u in ( union ( rng (qq | ( Seg j)))) by A29, XBOOLE_0:def 4;

                        u in ax2 & ax2 in RA by A83, A82, A81, XBOOLE_0:def 4, A80;

                        then

                         A85a: not u in (qq . (j + 1)) by A45, XBOOLE_0:def 5;

                        ( union ( rng (qq | ( Seg (j + 1))))) = ( union (( rng (qq | ( Seg j))) \/ {(qq . (j + 1))})) by A33, A32, FUNCT_1: 98;

                        then ( union ( rng (qq | ( Seg (j + 1))))) = (( union ( rng (qq | ( Seg j)))) \/ ( union {(qq . (j + 1))})) by ZFMISC_1: 78;

                        then not u in ( union ( rng (qq | ( Seg (j + 1))))) by A85, XBOOLE_0:def 3, A85a;

                        hence thesis by A75, A73, TARSKI:def 4;

                      end;

                      hence thesis;

                    end;

                    hence thesis by A70, A72, XBOOLE_0:def 4;

                  end;

                  hence thesis by A26;

                end;

                (( rng (qq | ( Seg n))) \/ ( Union h)) is a_partition of A

                proof

                  

                   A87: (( rng (qq | ( Seg n))) \/ ( Union h)) c= ( bool A)

                  proof

                    let x be object;

                    assume

                     A88: x in (( rng (qq | ( Seg n))) \/ ( Union h));

                    

                     A89: x in ( rng (qq | ( Seg n))) implies x in ( bool A)

                    proof

                      assume x in ( rng (qq | ( Seg n)));

                      then x in (( rng (qq | ( Seg j))) \/ {(qq . (j + 1))}) by A26, A33, A32, FUNCT_1: 98;

                      then x in ( rng (qq | ( Seg j))) or x in {(qq . (j + 1))} by XBOOLE_0:def 3;

                      then

                       A90: x in ( rng (qq | ( Seg j))) or x = (qq . (j + 1)) by TARSKI:def 1;

                      x in ( rng (qq | ( Seg j))) implies x in ( bool A)

                      proof

                        assume x in ( rng (qq | ( Seg j)));

                        then x in (( rng (qq | ( Seg j))) \/ R1) by XBOOLE_1: 7, TARSKI:def 3;

                        hence thesis by A30;

                      end;

                      hence thesis by A90, A44;

                    end;

                    x in ( Union h) implies x in ( bool A)

                    proof

                      assume x in ( Union h);

                      then

                      consider y be set such that

                       A91: x in y and

                       A92: y in ( rng h) by TARSKI:def 4;

                      consider z be object such that

                       A93: z in ( dom h) and

                       A94: y = (h . z) by A92, FUNCT_1:def 3;

                      consider x1,x2 be set, px be finite Subset of S such that z = [x1, x2] and

                       A95: x1 in R1 & x2 in RA and y = px and

                       A96: y is a_partition of (x1 /\ x2) by A55, A56, A93, A94;

                      

                       A97: (x1 /\ x2) c= x2 by XBOOLE_1: 17;

                      (A \ (qq . (j + 1))) c= A by XBOOLE_1: 36;

                      then x2 c= A by A45, A95, XBOOLE_1: 1;

                      then (x1 /\ x2) c= A by A97, XBOOLE_1: 1;

                      then ( bool (x1 /\ x2)) c= ( bool A) by ZFMISC_1: 67;

                      then y c= ( bool A) by A96, XBOOLE_1: 1;

                      hence thesis by A91;

                    end;

                    hence thesis by A88, A89, XBOOLE_0:def 3;

                  end;

                  

                   A98: ( union (( rng (qq | ( Seg n))) \/ ( Union h))) = A

                  proof

                    

                     A99: ( union (( rng (qq | ( Seg n))) \/ ( Union h))) c= A

                    proof

                      let x be object;

                      assume x in ( union (( rng (qq | ( Seg n))) \/ ( Union h)));

                      then

                      consider y be set such that

                       A100: x in y and

                       A101: y in (( rng (qq | ( Seg n))) \/ ( Union h)) by TARSKI:def 4;

                      thus thesis by A100, A87, A101;

                    end;

                    A c= ( union (( rng (qq | ( Seg n))) \/ ( Union h)))

                    proof

                      let x be object;

                      assume x in A;

                      then x in ( union (( rng (qq | ( Seg j))) \/ R1)) by A30, EQREL_1:def 4;

                      then

                       A102: x in (( union ( rng (qq | ( Seg j)))) \/ ( union R1)) by ZFMISC_1: 78;

                      

                       A103: x in ( union ( rng (qq | ( Seg j)))) implies x in ( union ( rng (qq | ( Seg (j + 1)))))

                      proof

                        assume

                         A104: x in ( union ( rng (qq | ( Seg j))));

                        ( union ( rng (qq | ( Seg j)))) c= ( union ( rng (qq | ( Seg (j + 1))))) by ZFMISC_1: 77, A33, XBOOLE_1: 7;

                        hence thesis by A104;

                      end;

                      x in ( union R1) implies x in ( union ( Union h)) or x in ( union ( rng (qq | ( Seg (j + 1)))))

                      proof

                        assume

                         A105: x in ( union R1);

                        ( union R1) c= (( union R1) \/ ( union ( rng (qq | ( Seg j))))) by XBOOLE_1: 7;

                        then ( union R1) c= ( union (R1 \/ ( rng (qq | ( Seg j))))) by ZFMISC_1: 78;

                        then

                         A106: ( union R1) c= A by A30, EQREL_1:def 4;

                        

                         A107: x in (qq . (j + 1)) implies x in ( union ( rng (qq | ( Seg (j + 1)))))

                        proof

                          assume

                           A108: x in (qq . (j + 1));

                          ( union ( rng (qq | ( Seg (j + 1))))) = ( union (( rng (qq | ( Seg j))) \/ {(qq . (j + 1))})) by A33, A32, FUNCT_1: 98;

                          then

                           A108aa: ( union ( rng (qq | ( Seg (j + 1))))) = (( union ( rng (qq | ( Seg j)))) \/ ( union {(qq . (j + 1))})) by ZFMISC_1: 78;

                          (qq . (j + 1)) c= ( union ( rng (qq | ( Seg (j + 1))))) by A108aa, XBOOLE_1: 7;

                          hence thesis by A108;

                        end;

                         not x in (qq . (j + 1)) implies x in ( union ( Union h))

                        proof

                          assume not x in (qq . (j + 1));

                          then x in (A \ (qq . (j + 1))) by A105, A106, XBOOLE_0:def 5;

                          then x in ( union RA) by A45, EQREL_1:def 4;

                          then

                          consider y be set such that

                           A109: x in y and

                           A110: y in RA by TARSKI:def 4;

                          consider z be set such that

                           A111: x in z and

                           A112: z in R1 by A105, TARSKI:def 4;

                          consider t be set such that

                           A113: t = [z, y];

                          

                           A114: [z, y] in [:R1, RA:] by A110, A112, ZFMISC_1:def 2;

                          

                           A115: [z, y] in ( dom h) by A110, A112, ZFMISC_1:def 2, A55;

                          consider x1,x2 be set, px be finite Subset of S such that

                           A116: t = [x1, x2] and x1 in R1 & x2 in RA and (h . t) = px and

                           A117: (h . t) is a_partition of (x1 /\ x2) by A113, A56, A114;

                          

                           A118: z = x1 & y = x2 by A113, A116, XTUPLE_0: 1;

                          x in (z /\ y) by A109, A111, XBOOLE_0:def 4;

                          then

                           A119: x in ( union (h . t)) by A117, A118, EQREL_1:def 4;

                          (h . t) in ( rng h) by A113, A115, FUNCT_1:def 3;

                          then ( union (h . t)) c= ( union ( union ( rng h))) by ZFMISC_1: 74, ZFMISC_1: 77;

                          hence thesis by A119;

                        end;

                        hence thesis by A107;

                      end;

                      then x in (( union ( rng (qq | ( Seg (j + 1))))) \/ ( union ( Union h))) by A102, A103, XBOOLE_0:def 3;

                      hence thesis by ZFMISC_1: 78, A26;

                    end;

                    hence thesis by A99;

                  end;

                  for a be Subset of A st a in (( rng (qq | ( Seg n))) \/ ( Union h)) holds a <> {} & for b be Subset of A st b in (( rng (qq | ( Seg n))) \/ ( Union h)) holds a = b or a misses b

                  proof

                    let a be Subset of A;

                    assume

                     A120: a in (( rng (qq | ( Seg n))) \/ ( Union h));

                    

                     A121: a in (( rng (qq | ( Seg j))) \/ {(qq . (j + 1))}) or a in ( Union h) by A34, A120, A26, XBOOLE_0:def 3;

                    

                     A122: a <> {}

                    proof

                      

                       A123: a in ( rng (qq | ( Seg (j + 1)))) implies a <> {}

                      proof

                        assume a in ( rng (qq | ( Seg (j + 1))));

                        then

                         A124: a in (( rng (qq | ( Seg j))) \/ {(qq . (j + 1))}) by A33, A32, FUNCT_1: 98;

                        

                         A125: a in ( rng (qq | ( Seg j))) implies a <> {}

                        proof

                          assume

                           A126: a in ( rng (qq | ( Seg j)));

                          ( rng (qq | ( Seg j))) c= (( rng (qq | ( Seg j))) \/ R1) by XBOOLE_1: 7;

                          hence thesis by A126, A30;

                        end;

                        a in {(qq . (j + 1))} implies a <> {}

                        proof

                          assume a in {(qq . (j + 1))};

                          then a = (qq . (j + 1)) by TARSKI:def 1;

                          hence thesis by A7, A32;

                        end;

                        hence thesis by A124, A125, XBOOLE_0:def 3;

                      end;

                      a in ( Union h) implies a <> {}

                      proof

                        assume a in ( Union h);

                        then

                        consider a1 be set such that

                         A127: a in a1 and

                         A128: a1 in ( rng h) by TARSKI:def 4;

                        consider a2 be object such that

                         A129: a2 in ( dom h) and

                         A130: a1 = (h . a2) by A128, FUNCT_1:def 3;

                        consider x1,x2 be set, px be finite Subset of S such that a2 = [x1, x2] & x1 in R1 & x2 in RA & a1 = px and

                         A131: a1 is a_partition of (x1 /\ x2) by A129, A55, A56, A130;

                        thus thesis by A127, A131;

                      end;

                      hence thesis by A120, A26, XBOOLE_0:def 3, A123;

                    end;

                    for b be Subset of A st b in (( rng (qq | ( Seg n))) \/ ( Union h)) holds a = b or a misses b

                    proof

                      let b be Subset of A;

                      assume b in (( rng (qq | ( Seg n))) \/ ( Union h));

                      then b in ( rng (qq | ( Seg (j + 1)))) or b in ( Union h) by A26, XBOOLE_0:def 3;

                      then

                       A132: b in (( rng (qq | ( Seg j))) \/ {(qq . (j + 1))}) or b in ( Union h) by A33, A32, FUNCT_1: 98;

                      

                       A133: b in ( rng (qq | ( Seg j))) implies a = b or a misses b

                      proof

                        assume

                         A134: b in ( rng (qq | ( Seg j)));

                        then

                         A135: b in (( rng (qq | ( Seg j))) \/ R1) by XBOOLE_1: 7, TARSKI:def 3;

                        

                         A136: a in ( rng (qq | ( Seg j))) implies a = b or a misses b

                        proof

                          assume a in ( rng (qq | ( Seg j)));

                          then a in (( rng (qq | ( Seg j))) \/ R1) by XBOOLE_1: 7, TARSKI:def 3;

                          hence thesis by A135, A30, EQREL_1:def 4;

                        end;

                        

                         A137: a in {(qq . (j + 1))} implies a = b or a misses b

                        proof

                          assume a in {(qq . (j + 1))};

                          then a misses ( Union (qq | ( Seg j))) by A36, TARSKI:def 1;

                          hence thesis by XBOOLE_1: 63, A134, ZFMISC_1: 74;

                        end;

                        a in ( Union h) implies a = b or a misses b

                        proof

                          assume a in ( Union h);

                          then

                           A138: a c= ( union ( Union h)) by ZFMISC_1: 74;

                          ( rng (qq | ( Seg j))) c= ( rng (qq | ( Seg (j + 1)))) by A33, XBOOLE_1: 7;

                          then b c= ( union ( rng (qq | ( Seg n)))) by A134, A26, ZFMISC_1: 74;

                          hence thesis by A138, A68, XBOOLE_1: 64;

                        end;

                        hence thesis by A121, XBOOLE_0:def 3, A136, A137;

                      end;

                      

                       A139: b in {(qq . (j + 1))} implies a = b or a misses b

                      proof

                        assume

                         A140: b in {(qq . (j + 1))};

                        

                         A141: a in ( rng (qq | ( Seg j))) implies a = b or a misses b

                        proof

                          assume

                           A142: a in ( rng (qq | ( Seg j)));

                          b misses ( Union (qq | ( Seg j))) by A140, TARSKI:def 1, A36;

                          hence thesis by A142, ZFMISC_1: 74, XBOOLE_1: 63;

                        end;

                        

                         A143: a in {(qq . (j + 1))} implies a = b or a misses b

                        proof

                          assume a in {(qq . (j + 1))};

                          then a = (qq . (j + 1)) & b = (qq . (j + 1)) by A140, TARSKI:def 1;

                          hence thesis;

                        end;

                        a in ( Union h) implies a = b or a misses b

                        proof

                          assume a in ( Union h);

                          then

                          consider a1 be set such that

                           A144: a in a1 and

                           A145: a1 in ( rng h) by TARSKI:def 4;

                          consider t be object such that

                           A146: t in ( dom h) and

                           A147: a1 = (h . t) by A145, FUNCT_1:def 3;

                          consider x1,x2 be set, px be finite Subset of S such that t = [x1, x2] and

                           A148: x1 in R1 & x2 in RA and a1 = px and

                           A149: a1 is a_partition of (x1 /\ x2) by A146, A147, A55, A56;

                          (x1 /\ x2) c= x2 by XBOOLE_1: 17;

                          then (x1 /\ x2) c= (A \ (qq . (j + 1))) by A45, A148, XBOOLE_1: 1;

                          then

                           A150: ( bool (x1 /\ x2)) c= ( bool (A \ (qq . (j + 1)))) by ZFMISC_1: 67;

                          

                           A151: a1 c= ( bool (A \ (qq . (j + 1)))) by A149, A150, XBOOLE_1: 1;

                          b = (qq . (j + 1)) by A140, TARSKI:def 1;

                          hence thesis by A151, A144, XBOOLE_1: 63, XBOOLE_1: 79;

                        end;

                        hence thesis by A121, XBOOLE_0:def 3, A141, A143;

                      end;

                      b in ( Union h) implies a = b or a misses b

                      proof

                        assume

                         A152: b in ( Union h);

                        

                         A153: a in ( rng (qq | ( Seg j))) implies a = b or a misses b

                        proof

                          assume

                           A154: a in ( rng (qq | ( Seg j)));

                          

                           A155: b c= ( union ( Union h)) by A152, ZFMISC_1: 74;

                          ( rng (qq | ( Seg j))) c= ( rng (qq | ( Seg (j + 1)))) by A33, XBOOLE_1: 7;

                          then a c= ( union ( rng (qq | ( Seg n)))) by A154, A26, ZFMISC_1: 74;

                          hence thesis by A155, A68, XBOOLE_1: 64;

                        end;

                        

                         A156: a in {(qq . (j + 1))} implies a = b or a misses b

                        proof

                          assume a in {(qq . (j + 1))};

                          then

                           A157: a = (qq . (j + 1)) by TARSKI:def 1;

                          consider b1 be set such that

                           A158: b in b1 and

                           A159: b1 in ( rng h) by A152, TARSKI:def 4;

                          consider tb be object such that

                           A160: tb in ( dom h) and

                           A161: b1 = (h . tb) by A159, FUNCT_1:def 3;

                          consider bx1,bx2 be set, bpx be finite Subset of S such that tb = [bx1, bx2] and

                           A162: bx1 in R1 & bx2 in RA and b1 = bpx and

                           A163: b1 is a_partition of (bx1 /\ bx2) by A160, A161, A55, A56;

                          

                           A164: ( bool (bx1 /\ bx2)) c= ( bool bx2) by XBOOLE_1: 17, ZFMISC_1: 67;

                          b1 c= ( bool bx2) by A163, A164, XBOOLE_1: 1;

                          then b c= (A \ (qq . (j + 1))) by A45, A162, A158, XBOOLE_1: 1;

                          hence thesis by XBOOLE_1: 79, A157, XBOOLE_1: 63;

                        end;

                        a in ( Union h) implies a = b or a misses b

                        proof

                          assume a in ( Union h);

                          then

                          consider a1 be set such that

                           A166: a in a1 and

                           A167: a1 in ( rng h) by TARSKI:def 4;

                          consider t be object such that

                           A168: t in ( dom h) and

                           A169: a1 = (h . t) by A167, FUNCT_1:def 3;

                          consider x1,x2 be set, px be finite Subset of S such that

                           A170: t = [x1, x2] and

                           A171: x1 in R1 & x2 in RA and a1 = px and

                           A172: a1 is a_partition of (x1 /\ x2) by A168, A169, A55, A56;

                          consider b1 be set such that

                           A173: b in b1 and

                           A174: b1 in ( rng h) by A152, TARSKI:def 4;

                          consider tb be object such that

                           A175: tb in ( dom h) and

                           A176: b1 = (h . tb) by A174, FUNCT_1:def 3;

                          consider bx1,bx2 be set, bpx be finite Subset of S such that

                           A177: tb = [bx1, bx2] and

                           A178: bx1 in R1 & bx2 in RA and b1 = bpx and

                           A179: b1 is a_partition of (bx1 /\ bx2) by A175, A176, A55, A56;

                          

                           A180: not x1 = bx1 & not x2 = bx2 implies thesis

                          proof

                            assume

                             A181: not x1 = bx1 & not x2 = bx2;

                            

                             A182: x1 in (( rng (qq | ( Seg j))) \/ R1) & bx1 in (( rng (qq | ( Seg j))) \/ R1) by A171, A178, XBOOLE_1: 7, TARSKI:def 3;

                            

                             A183: ( bool (x1 /\ x2)) c= ( bool x1) & ( bool (bx1 /\ bx2)) c= ( bool bx1) by XBOOLE_1: 17, ZFMISC_1: 67;

                            a1 c= ( bool x1) & b1 c= ( bool bx1) by A172, A179, A183, XBOOLE_1: 1;

                            hence thesis by A182, A181, A30, EQREL_1:def 4, A166, A173, XBOOLE_1: 64;

                          end;

                          

                           A184: x1 = bx1 & not x2 = bx2 implies thesis

                          proof

                            assume

                             A185: x1 = bx1 & not x2 = bx2;

                            

                             A186: ( bool (x1 /\ x2)) c= ( bool x2) & ( bool (bx1 /\ bx2)) c= ( bool bx2) by XBOOLE_1: 17, ZFMISC_1: 67;

                            a1 c= ( bool x2) & b1 c= ( bool bx2) by A172, A179, A186, XBOOLE_1: 1;

                            hence thesis by A166, A173, A185, A171, A178, A45, EQREL_1:def 4, XBOOLE_1: 64;

                          end;

                           not x1 = bx1 & x2 = bx2 implies thesis

                          proof

                            assume

                             A187: not x1 = bx1 & x2 = bx2;

                            

                             A188: x1 in (( rng (qq | ( Seg j))) \/ R1) & bx1 in (( rng (qq | ( Seg j))) \/ R1) by A171, A178, XBOOLE_1: 7, TARSKI:def 3;

                            

                             A189: ( bool (x1 /\ x2)) c= ( bool x1) & ( bool (bx1 /\ bx2)) c= ( bool bx1) by XBOOLE_1: 17, ZFMISC_1: 67;

                            a1 c= ( bool x1) & b1 c= ( bool bx1) by A172, A179, A189, XBOOLE_1: 1;

                            hence thesis by A166, A173, XBOOLE_1: 64, A188, A187, A30, EQREL_1:def 4;

                          end;

                          hence thesis by A169, A176, A170, A177, A166, A173, A172, EQREL_1:def 4, A180, A184;

                        end;

                        hence thesis by A121, XBOOLE_0:def 3, A153, A156;

                      end;

                      hence thesis by A132, XBOOLE_0:def 3, A133, A139;

                    end;

                    hence thesis by A122;

                  end;

                  hence thesis by A87, A98, EQREL_1:def 4;

                end;

                hence thesis by A65, A57, A68;

              end;

            end;

              suppose not j <= ( len qq);

              hence thesis by A28, A26, XREAL_1: 39;

            end;

          end;

          hence thesis;

        end;

        

         A190: for i be Nat st 1 <= i holds P[i] from NAT_1:sch 8( A14, A23);

        

         A191: ( len qq) is Nat & 1 <= ( len qq) by A13, FINSEQ_1: 20;

        consider R be finite Subset of S such that

         A192: ( union R) misses ( union ( rng (qq | ( Seg ( len qq))))) and

         A193: (( rng (qq | ( Seg ( len qq)))) \/ R) is a_partition of A by A190, A191;

        ( rng (qq | ( Seg ( len qq)))) = Q

        proof

          ( rng (qq | ( Seg ( len qq)))) = ( rng (qq | ( dom qq))) by FINSEQ_1:def 3

          .= ( rng qq);

          hence thesis by A6;

        end;

        hence thesis by A193, A192;

      end;

    end;

    definition

      let X be set;

      let S be Subset-Family of X;

      :: SRINGS_1:def1

      attr S is cap-finite-partition-closed means

      : Defcap: for S1,S2 be Element of S st (S1 /\ S2) is non empty holds ex x be finite Subset of S st x is a_partition of (S1 /\ S2);

    end

    registration

      let X be set;

      cluster ( cobool X) -> cap-finite-partition-closed;

      coherence by Lem4;

    end

    registration

      let X be set;

      cluster cap-finite-partition-closed for Subset-Family of X;

      existence

      proof

        take ( cobool X);

        thus thesis;

      end;

    end

    registration

      let X be set;

      cluster cap-closed -> cap-finite-partition-closed for Subset-Family of X;

      coherence

      proof

        let S be Subset-Family of X;

        assume

         A1: S is cap-closed;

        for S1,S2 be Element of S st (S1 /\ S2) is non empty holds ex y be finite Subset of S st y is a_partition of (S1 /\ S2)

        proof

          let S1,S2 be Element of S;

          per cases ;

            suppose

             A2: S is non empty;

            assume

             A3: (S1 /\ S2) is non empty;

            take {(S1 /\ S2)};

             {(S1 /\ S2)} c= S

            proof

              let x be object;

              assume x in {(S1 /\ S2)};

              then x = (S1 /\ S2) by TARSKI:def 1;

              hence thesis by A1, A2;

            end;

            hence thesis by A3, EQREL_1: 39;

          end;

            suppose S is empty;

            then S1 is empty & S2 is empty by SUBSET_1:def 1;

            hence thesis;

          end;

        end;

        hence thesis;

      end;

    end

    

     Lem7: for S be cap-finite-partition-closed Subset-Family of X holds for S1,S2 be Element of S holds ex P be finite Subset of S st P is a_partition of (S1 /\ S2)

    proof

      let S be cap-finite-partition-closed Subset-Family of X;

      let S1,S2 be Element of S;

      per cases ;

        suppose (S1 /\ S2) is non empty;

        then

        consider P be finite Subset of S such that

         A1: P is a_partition of (S1 /\ S2) by Defcap;

        thus thesis by A1;

      end;

        suppose

         A2: (S1 /\ S2) is empty;

         {} is finite Subset of S by SUBSET_1: 1;

        hence thesis by A2, EQREL_1: 45;

      end;

    end;

    

     Th1: for X be set, S be cap-finite-partition-closed Subset-Family of X, P1,P2 be finite Subset of S holds for y be non empty set st y in ( INTERSECTION (P1,P2)) holds ex P be finite Subset of S st P is a_partition of y

    proof

      let X be set, S be cap-finite-partition-closed Subset-Family of X, P1,P2 be finite Subset of S;

      let y be non empty set;

      assume

       A1: y in ( INTERSECTION (P1,P2));

      consider p1,p2 be set such that

       A2: p1 in P1 & p2 in P2 & y = (p1 /\ p2) by A1, SETFAM_1:def 5;

      consider P be finite Subset of S such that

       A3: P is a_partition of (p1 /\ p2) by A2, Defcap;

      thus thesis by A2, A3;

    end;

    theorem :: SRINGS_1:4

    

     ThmJ1: for A be non empty set, S be cap-finite-partition-closed Subset-Family of X, P1,P2 be a_partition of A st P1 is finite Subset of S & P2 is finite Subset of S holds ex P be a_partition of A st P is finite Subset of S & P '<' (P1 '/\' P2)

    proof

      let x be non empty set, S be cap-finite-partition-closed Subset-Family of X;

      let P1,P2 be a_partition of x;

      assume that

       A1: P1 is finite Subset of S and

       A2: P2 is finite Subset of S;

      defpred F[ object, object] means $1 in (P1 '/\' P2) & $2 is finite Subset of S & ex A be set st A = $1 & $2 is a_partition of A;

      set FOUT = { y where y be finite Subset of S : ex t be set st t in (P1 '/\' P2) & y is a_partition of t };

      FOUT c= ( bool ( bool x))

      proof

        let u be object;

        assume u in FOUT;

        then

        consider y be finite Subset of S such that

         A3: u = y and

         A4: ex t be set st t in (P1 '/\' P2) & y is a_partition of t;

        consider t0 be set such that

         A5: t0 in (P1 '/\' P2) and

         A6: y is a_partition of t0 by A4;

        reconsider u as set by TARSKI: 1;

        u c= ( bool x)

        proof

          let v be object;

          assume

           A7: v in u;

          

           A8: v in ( bool t0) by A3, A6, A7;

          ( bool t0) c= ( bool x) by A5, ZFMISC_1: 67;

          hence thesis by A8;

        end;

        hence thesis;

      end;

      then

       A9: ( union FOUT) c= ( union ( bool ( bool x))) by ZFMISC_1: 77;

      

       A10: for u be object st u in (P1 '/\' P2) holds ex v be object st v in FOUT & F[u, v]

      proof

        let u be object;

        assume

         A11: u in (P1 '/\' P2);

        reconsider u as set by TARSKI: 1;

        consider P be finite Subset of S such that

         A12: P is a_partition of u by A1, A2, A11, Th1;

        

         A13: P in FOUT by A11, A12;

        thus thesis by A11, A12, A13;

      end;

      consider f be Function such that

       A14: ( dom f) = (P1 '/\' P2) & ( rng f) c= FOUT and

       A15: for x be object st x in (P1 '/\' P2) holds F[x, (f . x)] from FUNCT_1:sch 6( A10);

      

       A16: ( Union f) is finite Subset of S

      proof

        

         A17: ( Union f) c= S

        proof

          let u be object;

          assume u in ( Union f);

          then

          consider v be set such that

           A18: u in v and

           A19: v in ( rng f) by TARSKI:def 4;

          consider w be object such that

           A20: w in (P1 '/\' P2) & v = (f . w) by A14, A19, FUNCT_1:def 3;

          v is Subset of S by A15, A20;

          hence thesis by A18;

        end;

        ( Union f) is finite

        proof

          for u be object st u in ( dom f) holds (f . u) is finite by A14, A15;

          hence thesis by A1, A2, A14, CARD_2: 88;

        end;

        hence thesis by A17;

      end;

      

       A22: ( Union f) is a_partition of x

      proof

        

         A23: ( Union f) c= ( bool x)

        proof

          

           A24: ( Union f) c= ( union FOUT) by A14, ZFMISC_1: 77;

          ( union FOUT) c= ( bool x) by A9, ZFMISC_1: 81;

          hence thesis by A24, XBOOLE_1: 1;

        end;

        

         A25: ( union ( Union f)) = x

        proof

          thus ( union ( Union f)) c= x

          proof

            ( union ( Union f)) c= ( union ( bool x)) by A23, ZFMISC_1: 77;

            hence thesis by ZFMISC_1: 81;

          end;

          thus x c= ( union ( Union f))

          proof

            let a be object;

            assume a in x;

            then

             A27: a in ( union P1) & a in ( union P2) by EQREL_1:def 4;

            consider b1 be set such that

             A28: a in b1 and

             A29: b1 in P1 by A27, TARSKI:def 4;

            consider b2 be set such that

             A30: a in b2 and

             A31: b2 in P2 by A27, TARSKI:def 4;

            

             A32: (b1 /\ b2) in ( INTERSECTION (P1,P2)) by A29, A31, SETFAM_1:def 5;

             not (b1 /\ b2) = {} by A28, A30, XBOOLE_0:def 4;

            then not (b1 /\ b2) in { {} } by TARSKI:def 1;

            then

             A33: (b1 /\ b2) in (P1 '/\' P2) by A32, XBOOLE_0:def 5;

            then F[(b1 /\ b2), (f . (b1 /\ b2))] by A15;

            then ( union (f . (b1 /\ b2))) = (b1 /\ b2) by EQREL_1:def 4;

            then

             A34: a in ( union (f . (b1 /\ b2))) by A28, A30, XBOOLE_0:def 4;

            

             A35: (f . (b1 /\ b2)) in ( rng f) by A14, A33, FUNCT_1:def 3;

            consider bb be set such that

             A36: a in bb and

             A37: bb in (f . (b1 /\ b2)) by A34, TARSKI:def 4;

            bb in ( Union f) by A35, A37, TARSKI:def 4;

            hence thesis by A36, TARSKI:def 4;

          end;

        end;

        for A be Subset of x st A in ( Union f) holds A <> {} & for B be Subset of x st B in ( Union f) holds A = B or A misses B

        proof

          let A be Subset of x;

          assume A in ( Union f);

          then

          consider b be set such that

           A38: A in b & b in ( rng f) by TARSKI:def 4;

          consider c be object such that

           A39: c in ( dom f) and

           A40: b = (f . c) by A38, FUNCT_1:def 3;

          reconsider c as set by TARSKI: 1;

          

           A41: F[c, (f . c)] by A14, A15, A39;

          for B be Subset of x st B in ( Union f) holds A = B or A misses B

          proof

            let B be Subset of x;

            assume B in ( Union f);

            then

            consider b2 be set such that

             A42: B in b2 & b2 in ( rng f) by TARSKI:def 4;

            consider c2 be object such that

             A43: c2 in ( dom f) and

             A44: b2 = (f . c2) by A42, FUNCT_1:def 3;

            per cases ;

              suppose c = c2;

              hence thesis by A38, A40, A41, A42, A44, EQREL_1:def 4;

            end;

              suppose

               A45: not c = c2;

              consider p11,p21 be set such that

               A46: p11 in P1 and

               A47: p21 in P2 and

               A48: c = (p11 /\ p21) by A14, A39, SETFAM_1:def 5;

              consider p12,p22 be set such that

               A49: p12 in P1 and

               A50: p22 in P2 and

               A51: c2 = (p12 /\ p22) by A14, A43, SETFAM_1:def 5;

              

               A52: not (p11 /\ p21) c= (p12 /\ p22) implies A = B or A misses B

              proof

                assume not (p11 /\ p21) c= (p12 /\ p22);

                then

                consider u be object such that

                 A53: u in (p11 /\ p21) and

                 A54: not u in (p12 /\ p22) by TARSKI:def 3;

                

                 A55: u in p11 & u in p21 & not u in p12 implies A = B or A misses B

                proof

                  assume

                   A56: u in p11 & u in p21 & not u in p12;

                   F[c, (f . c)] & F[c2, (f . c2)] by A14, A15, A39, A43;

                  then ( union (f . c)) = (p11 /\ p21) & ( union (f . c2)) = (p12 /\ p22) by A48, A51, EQREL_1:def 4;

                  then

                   A57: ( union (f . c)) c= p11 & ( union (f . c2)) c= p12 & p11 misses p12 by A46, A49, A56, EQREL_1:def 4, XBOOLE_1: 17;

                  A c= ( union (f . c)) & B c= ( union (f . c2)) by A38, A40, A42, A44, ZFMISC_1: 74;

                  then A c= p11 & B c= p12 & p11 misses p12 by A57, XBOOLE_1: 1;

                  hence thesis by XBOOLE_1: 64;

                end;

                u in p11 & u in p21 & not u in p22 implies A = B or A misses B

                proof

                  assume

                   A58: u in p11 & u in p21 & not u in p22;

                   F[c, (f . c)] & F[c2, (f . c2)] by A14, A15, A39, A43;

                  then ( union (f . c)) = (p11 /\ p21) & ( union (f . c2)) = (p12 /\ p22) by A48, A51, EQREL_1:def 4;

                  then

                   A59: ( union (f . c)) c= p21 & ( union (f . c2)) c= p22 & p21 misses p22 by A47, A50, A58, EQREL_1:def 4, XBOOLE_1: 17;

                  A c= ( union (f . c)) & B c= ( union (f . c2)) by A38, A40, A42, A44, ZFMISC_1: 74;

                  then A c= p21 & B c= p22 & p21 misses p22 by A59, XBOOLE_1: 1;

                  hence thesis by XBOOLE_1: 64;

                end;

                hence thesis by A53, A54, A55, XBOOLE_0:def 4;

              end;

               not (p12 /\ p22) c= (p11 /\ p21) implies A = B or A misses B

              proof

                assume not (p12 /\ p22) c= (p11 /\ p21);

                then

                consider u be object such that

                 A60: u in (p12 /\ p22) and

                 A61: not u in (p11 /\ p21) by TARSKI:def 3;

                

                 A62: u in p12 & u in p22 & not u in p11 implies A = B or A misses B

                proof

                  assume

                   A63: u in p12 & u in p22 & not u in p11;

                   F[c, (f . c)] & F[c2, (f . c2)] by A14, A15, A39, A43;

                  then ( union (f . c)) = (p11 /\ p21) & ( union (f . c2)) = (p12 /\ p22) by A48, A51, EQREL_1:def 4;

                  then

                   A64: ( union (f . c)) c= p11 & ( union (f . c2)) c= p12 & p11 misses p12 by A46, A49, A63, EQREL_1:def 4, XBOOLE_1: 17;

                  A c= ( union (f . c)) & B c= ( union (f . c2)) by A38, A40, A42, A44, ZFMISC_1: 74;

                  then A c= p11 & B c= p12 & p11 misses p12 by A64, XBOOLE_1: 1;

                  hence thesis by XBOOLE_1: 64;

                end;

                u in p12 & u in p22 & not u in p21 implies A = B or A misses B

                proof

                  assume

                   A65: u in p12 & u in p22 & not u in p21;

                   F[c, (f . c)] & F[c2, (f . c2)] by A14, A15, A39, A43;

                  then ( union (f . c)) = (p11 /\ p21) & ( union (f . c2)) = (p12 /\ p22) by A48, A51, EQREL_1:def 4;

                  then

                   A66: ( union (f . c)) c= p21 & ( union (f . c2)) c= p22 & p21 misses p22 by A47, A50, A65, EQREL_1:def 4, XBOOLE_1: 17;

                  A c= ( union (f . c)) & B c= ( union (f . c2)) by A38, A40, A42, A44, ZFMISC_1: 74;

                  then A c= p21 & B c= p22 & p21 misses p22 by A66, XBOOLE_1: 1;

                  hence thesis by XBOOLE_1: 64;

                end;

                hence thesis by A60, A61, A62, XBOOLE_0:def 4;

              end;

              hence thesis by A45, A48, A51, A52, XBOOLE_0:def 10;

            end;

          end;

          hence thesis by A38, A40, A41;

        end;

        hence thesis by A23, A25, EQREL_1:def 4;

      end;

      ( Union f) '<' (P1 '/\' P2)

      proof

        for a be set st a in ( Union f) holds ex b be set st b in (P1 '/\' P2) & a c= b

        proof

          let a be set;

          assume a in ( Union f);

          then

          consider b be set such that

           A67: a in b and

           A68: b in ( rng f) by TARSKI:def 4;

          consider c be object such that

           A69: c in ( dom f) and

           A70: b = (f . c) by A68, FUNCT_1:def 3;

          reconsider c as set by TARSKI: 1;

           F[c, (f . c)] by A14, A15, A69;

          hence thesis by A67, A70;

        end;

        hence thesis by SETFAM_1:def 2;

      end;

      hence thesis by A16, A22;

    end;

    theorem :: SRINGS_1:5

    

     V: for S be cap-finite-partition-closed Subset-Family of X holds for A,B be finite Subset of S st A is mutually-disjoint & B is mutually-disjoint holds ex P be finite Subset of S st P is a_partition of (( union A) /\ ( union B))

    proof

      let S be cap-finite-partition-closed Subset-Family of X;

      let A,B be finite Subset of S;

      assume that

       A1: A is mutually-disjoint and

       A2: B is mutually-disjoint;

      per cases ;

        suppose

         A3: [:A, B:] <> {} ;

        defpred F[ object, object] means ex a,b be set st a in A & b in B & $1 = [a, b] & ex p be finite Subset of S st p is a_partition of (a /\ b) & $2 = p;

        set XIN = the set of all s where s be Element of [:A, B:];

        set XOUT = { s where s be finite Subset of S : ex a,b be set st a in A & b in B & s is a_partition of (a /\ b) };

        

         A4: for x be object st x in XIN holds ex y be object st y in XOUT & F[x, y]

        proof

          let x be object;

          assume x in XIN;

          then

          consider s be Element of [:A, B:] such that

           A5: x = s;

          consider a0,b0 be object such that

           A6: a0 in A & b0 in B and

           A7: s = [a0, b0] by A3, ZFMISC_1:def 2;

          reconsider a0, b0 as set by TARSKI: 1;

          per cases ;

            suppose (a0 /\ b0) is non empty;

            then

            consider P be finite Subset of S such that

             A8: P is a_partition of (a0 /\ b0) by A6, Defcap;

            P in XOUT by A6, A8;

            hence thesis by A5, A6, A7, A8;

          end;

            suppose (a0 /\ b0) is empty;

            then

             A9: {} is finite Subset of S & {} is a_partition of (a0 /\ b0) by SUBSET_1: 1, EQREL_1: 45;

            then {} in XOUT by A6;

            hence thesis by A5, A6, A7, A9;

          end;

        end;

        consider f be Function such that

         A10: ( dom f) = XIN & ( rng f) c= XOUT and

         A11: for x be object st x in XIN holds F[x, (f . x)] from FUNCT_1:sch 6( A4);

        

         A12: ( Union f) is finite

        proof

          

           A13: [:A, B:] = XIN

          proof

            

             A14: [:A, B:] c= XIN

            proof

              let x be object;

              assume x in [:A, B:];

              hence thesis;

            end;

            XIN c= [:A, B:]

            proof

              let x be object;

              assume x in XIN;

              then

              consider s be Element of [:A, B:] such that

               A15: s = x;

              thus thesis by A3, A15;

            end;

            hence thesis by A14;

          end;

          for z be set st z in ( rng f) holds z is finite

          proof

            let z be set;

            assume z in ( rng f);

            then z in XOUT by A10;

            then

            consider s0 be finite Subset of S such that

             A16: s0 = z and ex a,b be set st a in A & b in B & s0 is a_partition of (a /\ b);

            thus thesis by A16;

          end;

          hence thesis by A13, A10, FINSET_1: 8, FINSET_1: 7;

        end;

        

         A17: ( Union f) c= S

        proof

          let x be object;

          assume x in ( Union f);

          then

          consider y be set such that

           A18: x in y & y in ( rng f) by TARSKI:def 4;

          y in XOUT by A18, A10;

          then

          consider s0 be finite Subset of S such that

           A19: y = s0 and ex a,b be set st a in A & b in B & s0 is a_partition of (a /\ b);

          thus thesis by A18, A19;

        end;

        

         A20: ( Union f) c= ( bool (( union A) /\ ( union B)))

        proof

          let x be object;

          assume x in ( Union f);

          then

          consider y be set such that

           A21: x in y and

           A22: y in ( rng f) by TARSKI:def 4;

          y in XOUT by A22, A10;

          then

          consider s0 be finite Subset of S such that

           A23: y = s0 and

           A24: ex a,b be set st a in A & b in B & s0 is a_partition of (a /\ b);

          reconsider x as set by TARSKI: 1;

          consider a0,b0 be set such that

           A25: a0 in A & b0 in B and

           A26: s0 is a_partition of (a0 /\ b0) by A24;

          a0 c= ( union A) & b0 c= ( union B) by A25, ZFMISC_1: 74;

          then (a0 /\ b0) c= (( union A) /\ ( union B)) by XBOOLE_1: 27;

          then x c= (( union A) /\ ( union B)) by XBOOLE_1: 1, A21, A23, A26;

          hence thesis;

        end;

        

         A27: ( union ( Union f)) = (( union A) /\ ( union B))

        proof

          

           A28: ( union ( Union f)) c= (( union A) /\ ( union B))

          proof

            ( union ( Union f)) c= ( union ( bool (( union A) /\ ( union B)))) by A20, ZFMISC_1: 77;

            hence thesis by ZFMISC_1: 81;

          end;

          (( union A) /\ ( union B)) c= ( union ( Union f))

          proof

            let x be object;

            assume x in (( union A) /\ ( union B));

            then

             A29: x in ( union A) & x in ( union B) by XBOOLE_0:def 4;

            then

            consider a be set such that

             A30: x in a & a in A by TARSKI:def 4;

            consider b be set such that

             A31: x in b & b in B by A29, TARSKI:def 4;

             [a, b] in [:A, B:] by A30, A31, ZFMISC_1:def 2;

            then

             A32: [a, b] in XIN;

            then F[ [a, b], (f . [a, b])] by A11;

            then

            consider a0,b0 be set such that a0 in A & b0 in B and

             A33: [a, b] = [a0, b0] and

             A34: ex p be finite Subset of S st p is a_partition of (a0 /\ b0) & (f . [a0, b0]) = p;

            consider p be finite Subset of S such that

             A35: p is a_partition of (a0 /\ b0) and

             A36: (f . [a0, b0]) = p by A34;

            

             A37: a0 = a & b0 = b by A33, XTUPLE_0: 1;

            (f . [a, b]) in ( rng f) by A32, A10, FUNCT_1:def 3;

            then

             A38: ( union (f . [a, b])) c= ( union ( union ( rng f))) by ZFMISC_1: 77, ZFMISC_1: 74;

            x in (a /\ b) by A30, A31, XBOOLE_0:def 4;

            then x in ( union (f . [a, b])) by A35, A36, A37, EQREL_1:def 4;

            hence thesis by A38;

          end;

          hence thesis by A28;

        end;

        for u be Subset of (( union A) /\ ( union B)) st u in ( Union f) holds u <> {} & for v be Subset of (( union A) /\ ( union B)) st v in ( Union f) holds u = v or u misses v

        proof

          let u be Subset of (( union A) /\ ( union B));

          assume u in ( Union f);

          then

          consider v be set such that

           A39: u in v and

           A40: v in ( rng f) by TARSKI:def 4;

          consider w be object such that

           A41: w in ( dom f) and

           A42: v = (f . w) by A40, FUNCT_1:def 3;

          consider x be Element of [:A, B:] such that

           A43: w = x by A41, A10;

          reconsider w as Element of [:A, B:] by A43;

          consider wa,wb be object such that wa in A & wb in B and

           A44: w = [wa, wb] by A3, ZFMISC_1:def 2;

          consider a,b be set such that

           A45: a in A & b in B and

           A46: [wa, wb] = [a, b] and

           A47: ex p be finite Subset of S st p is a_partition of (a /\ b) & (f . w) = p by A41, A10, A11, A44;

          consider p be finite Subset of S such that

           A48: p is a_partition of (a /\ b) and

           A49: (f . w) = p by A47;

          v in XOUT by A40, A10;

          then

          consider s0 be finite Subset of S such that

           A50: v = s0 and

           A51: ex a,b be set st a in A & b in B & s0 is a_partition of (a /\ b);

          consider a0,b0 be set such that a0 in A & b0 in B and

           A52: s0 is a_partition of (a0 /\ b0) by A51;

          thus u <> {} by A39, A50, A52;

          thus for v be Subset of (( union A) /\ ( union B)) st v in ( Union f) holds u = v or u misses v

          proof

            let jw be Subset of (( union A) /\ ( union B));

            assume jw in ( Union f);

            then

            consider lw0 be set such that

             A53: jw in lw0 and

             A54: lw0 in ( rng f) by TARSKI:def 4;

            consider lw be object such that

             A55: lw in ( dom f) and

             A56: lw0 = (f . lw) by A54, FUNCT_1:def 3;

            consider lx be Element of [:A, B:] such that

             A57: lw = lx by A55, A10;

            reconsider lw as Element of [:A, B:] by A57;

            consider lwa,lwb be object such that lwa in A & lwb in B and

             A58: lw = [lwa, lwb] by A3, ZFMISC_1:def 2;

            consider la,lb be set such that

             A59: la in A & lb in B and

             A60: [lwa, lwb] = [la, lb] and

             A61: ex p be finite Subset of S st p is a_partition of (la /\ lb) & (f . lw) = p by A55, A10, A11, A58;

            consider lp be finite Subset of S such that

             A62: lp is a_partition of (la /\ lb) and

             A63: (f . lw) = lp by A61;

            per cases ;

              suppose a = la & b = lb;

              hence thesis by A39, A42, A44, A46, A56, A58, A60, A63, A62, A53, EQREL_1:def 4;

            end;

              suppose

               A64: a <> la or b <> lb;

              (a /\ b) c= b & (la /\ lb) c= lb & (a /\ b) c= a & (la /\ lb) c= la by XBOOLE_1: 17;

              then (a /\ b) misses (la /\ lb) by A64, A45, A59, A1, A2, TAXONOM2:def 5, XBOOLE_1: 64;

              hence thesis by A39, A49, A48, A42, A56, A63, A62, A53, XBOOLE_1: 64;

            end;

          end;

        end;

        then ( Union f) is a_partition of (( union A) /\ ( union B)) by A20, A27, EQREL_1:def 4;

        hence thesis by A12, A17;

      end;

        suppose [:A, B:] = {} ;

        then A = {} or B = {} ;

        hence thesis by ZFMISC_1: 2, EQREL_1: 45;

      end;

    end;

    

     Lem8: for S be cap-finite-partition-closed Subset-Family of X holds for SM be FinSequence of S holds ex P be finite Subset of S st P is a_partition of ( meet ( rng SM))

    proof

      let S be cap-finite-partition-closed Subset-Family of X;

      let SM be FinSequence of S;

      per cases ;

        suppose

         A1: S is empty;

        then ( meet ( rng SM)) = {} by SETFAM_1: 1;

        hence thesis by A1, EQREL_1: 45;

      end;

        suppose

         A3: S is non empty;

        defpred P[ FinSequence] means ex p be finite Subset of S st p is a_partition of ( meet ( rng $1));

        

         A4: for p be FinSequence of S, x be Element of S st P[p] holds P[(p ^ <*x*>)]

        proof

          let p be FinSequence of S;

          let x be Element of S;

          assume

           A5: P[p];

          per cases ;

            suppose

             A6: ( rng p) = {} ;

            ( rng (p ^ <*x*>)) = (( rng p) \/ ( rng <*x*>)) by FINSEQ_1: 31;

            then

             A7: ( rng (p ^ <*x*>)) = {x} by A6, FINSEQ_1: 38;

            then

             A8: ( meet ( rng (p ^ <*x*>))) = x by SETFAM_1: 10;

            per cases ;

              suppose x is non empty;

              then {x} is finite Subset of S & {x} is a_partition of x by A3, SUBSET_1: 33, EQREL_1: 39;

              hence thesis by A8;

            end;

              suppose x is empty;

              then

               A9: ( meet ( rng (p ^ <*x*>))) = {} by A7, SETFAM_1: 10;

               {} is finite Subset of S & {} is a_partition of {} by SUBSET_1: 1, EQREL_1: 45;

              hence thesis by A9;

            end;

          end;

            suppose

             A10: ( rng p) <> {} ;

            consider pp be finite Subset of S such that

             A11: pp is a_partition of ( meet ( rng p)) by A5;

            defpred F[ object, object] means ex A1 be set st A1 = $1 & $1 is Element of S & $2 is finite Subset of S & $2 is a_partition of (A1 /\ x);

            set XIN = { s where s be Element of S : s in pp };

            

             A15: XIN c= pp

            proof

              let a be object;

              assume a in XIN;

              then ex a0 be Element of S st a = a0 & a0 in pp;

              hence thesis;

            end;

            set XOUT = { s where s be finite Subset of S : ex y be set st y in pp & s is a_partition of (y /\ x) };

            

             A17: for a be object st a in XIN holds ex b be object st b in XOUT & F[a, b]

            proof

              let a be object;

              assume a in XIN;

              then

              consider s0 be Element of S such that

               A18: a = s0 and

               A19: s0 in pp;

              per cases ;

                suppose (s0 /\ x) <> {} ;

                then

                consider ps be finite Subset of S such that

                 A20: ps is a_partition of (s0 /\ x) by Defcap;

                ps in XOUT & F[a, ps] by A18, A19, A20;

                hence thesis;

              end;

                suppose

                 A21: (s0 /\ x) = {} ;

                 {} is finite Subset of S & {} is a_partition of {} by SUBSET_1: 1, EQREL_1: 45;

                then {} in XOUT & F[a, {} ] by A18, A19, A21;

                hence thesis;

              end;

            end;

            consider f be Function such that

             A22: ( dom f) = XIN & ( rng f) c= XOUT and

             A23: for x be object st x in XIN holds F[x, (f . x)] from FUNCT_1:sch 6( A17);

            ( Union f) is finite Subset of S & ( Union f) is a_partition of ( meet ( rng (p ^ <*x*>)))

            proof

              

               A24: ( Union f) is finite

              proof

                for z be set st z in ( rng f) holds z is finite

                proof

                  let z be set;

                  assume z in ( rng f);

                  then

                  consider z0 be object such that

                   A25: z0 in XIN & z = (f . z0) by A22, FUNCT_1:def 3;

                   F[z0, (f . z0)] by A23, A25;

                  hence thesis by A25;

                end;

                hence thesis by A22, A15, FINSET_1: 7, FINSET_1: 8;

              end;

              

               A26: ( Union f) c= S

              proof

                let a be object;

                assume a in ( Union f);

                then

                consider b be set such that

                 A27: a in b and

                 A28: b in ( rng f) by TARSKI:def 4;

                consider c be object such that

                 A29: c in XIN & b = (f . c) by A22, A28, FUNCT_1:def 3;

                 F[c, (f . c)] by A23, A29;

                hence thesis by A27, A29;

              end;

              

               A30: ( Union f) c= ( bool ( meet ( rng (p ^ <*x*>))))

              proof

                let a be object;

                assume a in ( Union f);

                then

                consider b be set such that

                 A31: a in b and

                 A32: b in ( rng f) by TARSKI:def 4;

                reconsider a as set by TARSKI: 1;

                b in XOUT by A22, A32;

                then

                consider b0 be finite Subset of S such that

                 A33: b = b0 and

                 A34: ex y be set st y in pp & b0 is a_partition of (y /\ x);

                consider y0 be set such that

                 A35: y0 in pp and

                 A36: b0 is a_partition of (y0 /\ x) by A34;

                (y0 /\ x) c= (( meet ( rng p)) /\ x) by A35, A11, XBOOLE_1: 26;

                then

                 A37: (y0 /\ x) c= (( meet ( rng p)) /\ ( meet {x})) by SETFAM_1: 10;

                

                 A38: a c= (( meet ( rng p)) /\ ( meet {x})) by A31, A33, A36, A37, XBOOLE_1: 1;

                a c= ( meet (( rng p) \/ {x})) by A10, A38, SETFAM_1: 9;

                then a c= ( meet (( rng p) \/ ( rng <*x*>))) by FINSEQ_1: 38;

                then a c= ( meet ( rng (p ^ <*x*>))) by FINSEQ_1: 31;

                hence thesis;

              end;

              

               A39: ( union ( Union f)) = ( meet ( rng (p ^ <*x*>)))

              proof

                

                 A40: ( union ( Union f)) c= ( meet ( rng (p ^ <*x*>)))

                proof

                  ( union ( Union f)) c= ( union ( bool ( meet ( rng (p ^ <*x*>))))) by A30, ZFMISC_1: 77;

                  hence thesis by ZFMISC_1: 81;

                end;

                ( meet ( rng (p ^ <*x*>))) c= ( union ( Union f))

                proof

                  let a be object;

                  assume

                   A41: a in ( meet ( rng (p ^ <*x*>)));

                  ( rng (p ^ <*x*>)) = (( rng p) \/ ( rng <*x*>)) by FINSEQ_1: 31;

                  then

                   A42: ( meet ( rng (p ^ <*x*>))) = ( meet (( rng p) \/ {x})) by FINSEQ_1: 38;

                  ( meet ( rng (p ^ <*x*>))) = (( meet ( rng p)) /\ ( meet {x})) by A10, A42, SETFAM_1: 9;

                  then ( meet ( rng (p ^ <*x*>))) = (( meet ( rng p)) /\ x) by SETFAM_1: 10;

                  then a in (( union pp) /\ x) by A11, EQREL_1:def 4, A41;

                  then

                   A43: a in ( union pp) & a in x by XBOOLE_0:def 4;

                  then

                  consider a0 be set such that

                   A44: a in a0 & a0 in pp by TARSKI:def 4;

                  

                   A45: a0 in XIN by A44;

                  then F[a0, (f . a0)] by A23;

                  then

                   A46: ( union (f . a0)) = (a0 /\ x) by EQREL_1:def 4;

                  a in (a0 /\ x) by A44, A43, XBOOLE_0:def 4;

                  then

                  consider c0 be set such that

                   A47: a in c0 and

                   A48: c0 in (f . a0) by A46, TARSKI:def 4;

                  

                   A49: a in ( union (f . a0)) by A47, A48, TARSKI:def 4;

                  (f . a0) c= ( Union f)

                  proof

                    let b be object;

                    assume b in (f . a0);

                    then b in (f . a0) & (f . a0) in ( rng f) by A22, A45, FUNCT_1:def 3;

                    hence thesis by TARSKI:def 4;

                  end;

                  then ( union (f . a0)) c= ( union ( Union f)) by ZFMISC_1: 77;

                  hence thesis by A49;

                end;

                hence thesis by A40;

              end;

              for A be Subset of ( meet ( rng (p ^ <*x*>))) st A in ( Union f) holds A <> {} & for B be Subset of ( meet ( rng (p ^ <*x*>))) st B in ( Union f) holds A = B or A misses B

              proof

                let A be Subset of ( meet ( rng (p ^ <*x*>)));

                assume

                 A51: A in ( Union f);

                consider a0 be set such that

                 A52: A in a0 & a0 in ( rng f) by A51, TARSKI:def 4;

                consider b0 be object such that

                 A53: b0 in XIN and

                 A54: a0 = (f . b0) by A52, A22, FUNCT_1:def 3;

                reconsider b0 as set by TARSKI: 1;

                

                 A55: F[b0, (f . b0)] by A23, A53;

                hence A <> {} by A52, A54;

                thus for B be Subset of ( meet ( rng (p ^ <*x*>))) st B in ( Union f) holds A = B or A misses B

                proof

                  let B be Subset of ( meet ( rng (p ^ <*x*>)));

                  assume B in ( Union f);

                  then

                  consider d0 be set such that

                   A56: B in d0 & d0 in ( rng f) by TARSKI:def 4;

                  consider e0 be object such that

                   A57: e0 in XIN and

                   A58: d0 = (f . e0) by A56, A22, FUNCT_1:def 3;

                  reconsider e0 as set by TARSKI: 1;

                  

                   B02: F[e0, (f . e0)] by A23, A57;

                  consider b00 be Element of S such that

                   A59: b0 = b00 and

                   A60: b00 in pp by A53;

                  consider e00 be Element of S such that

                   A61: e0 = e00 and

                   A62: e00 in pp by A57;

                  per cases ;

                    suppose e00 = b00;

                    hence thesis by A52, A54, A56, A58, A59, A61, A55, EQREL_1:def 4;

                  end;

                    suppose

                     A63: not e00 = b00;

                    ( union (f . b0)) = (b0 /\ x) & ( union (f . e0)) = (e0 /\ x) by EQREL_1:def 4, A55, B02;

                    then ( union (f . b0)) c= b0 & ( union (f . e0)) c= e0 by XBOOLE_1: 17;

                    then

                     A64: ( union (f . b0)) misses ( union (f . e0)) by A63, A59, A61, A60, A62, A11, EQREL_1:def 4, XBOOLE_1: 64;

                    (A /\ B) c= {}

                    proof

                      let t be object;

                      assume t in (A /\ B);

                      then t in A & t in B by XBOOLE_0:def 4;

                      then t in ( union (f . b0)) & t in ( union (f . e0)) by A52, A54, A56, A58, TARSKI:def 4;

                      hence thesis by A64, XBOOLE_0:def 4;

                    end;

                    hence thesis;

                  end;

                end;

              end;

              hence thesis by A24, A26, A30, A39, EQREL_1:def 4;

            end;

            hence thesis;

          end;

        end;

        

         A65: P[( <*> S)]

        proof

           {} is Subset of S & {} is a_partition of {} by SUBSET_1: 1, EQREL_1: 45;

          hence thesis by SETFAM_1: 1;

        end;

        for p be FinSequence of S holds P[p] from FINSEQ_2:sch 2( A65, A4);

        then

        consider P be finite Subset of S such that

         A66: P is a_partition of ( meet ( rng SM));

        thus thesis by A66;

      end;

    end;

    theorem :: SRINGS_1:6

    for S be cap-finite-partition-closed Subset-Family of X holds for SM be finite Subset of S holds ex P be finite Subset of S st P is a_partition of ( meet SM)

    proof

      let S be cap-finite-partition-closed Subset-Family of X;

      let SM be finite Subset of S;

      consider SF be FinSequence such that

       A1: ( rng SF) = SM by FINSEQ_1: 52;

      SF is FinSequence of S by A1, FINSEQ_1:def 4;

      hence thesis by A1, Lem8;

    end;

    theorem :: SRINGS_1:7

    

     Thm86: for S be cap-finite-partition-closed Subset-Family of X holds { ( union x) where x be finite Subset of S : x is mutually-disjoint } is cap-closed

    proof

      let S be cap-finite-partition-closed Subset-Family of X;

      set Y = { ( union x) where x be finite Subset of S : x is mutually-disjoint };

      let a,b be set such that

       H3: a in Y and

       H4: b in Y;

      (a /\ b) in Y

      proof

        consider xa be finite Subset of S such that

         V1: a = ( union xa) and

         V2: xa is mutually-disjoint by H3;

        consider xb be finite Subset of S such that

         V3: b = ( union xb) and

         V4: xb is mutually-disjoint by H4;

        consider p be finite Subset of S such that

         K2: p is a_partition of (( union xa) /\ ( union xb)) by V2, V4, V;

        

         K3: ( union p) = (a /\ b) by V1, V3, K2, EQREL_1:def 4;

        for x,y be set st x in p & y in p & x <> y holds x misses y by K2, EQREL_1:def 4;

        then p is mutually-disjoint by TAXONOM2:def 5;

        hence thesis by K3;

      end;

      hence thesis;

    end;

    definition

      let X be set;

      let S be Subset-Family of X;

      :: SRINGS_1:def2

      attr S is diff-finite-partition-closed means

      : Defdiff: for S1,S2 be Element of S st (S1 \ S2) is non empty holds ex x be finite Subset of S st x is a_partition of (S1 \ S2);

    end

    registration

      let X be set;

      cluster ( cobool X) -> diff-finite-partition-closed;

      coherence by Lem4;

    end

    registration

      let X be set;

      cluster diff-finite-partition-closed for Subset-Family of X;

      existence

      proof

        take ( cobool X);

        thus thesis;

      end;

    end

    registration

      let X be set;

      cluster diff-closed -> diff-finite-partition-closed for Subset-Family of X;

      coherence

      proof

        let S be Subset-Family of X;

        assume

         A1: S is diff-closed;

        for S1,S2 be Element of S st (S1 \ S2) is non empty holds ex y be finite Subset of S st y is a_partition of (S1 \ S2)

        proof

          let S1,S2 be Element of S;

          per cases ;

            suppose

             A2: S is non empty;

            assume

             A3: (S1 \ S2) is non empty;

            take {(S1 \ S2)};

             {(S1 \ S2)} c= S

            proof

              let x be object;

              (S1 \ S2) in S by A1, A2;

              hence thesis by TARSKI:def 1;

            end;

            hence thesis by A3, EQREL_1: 39;

          end;

            suppose S is empty;

            hence thesis by SUBSET_1:def 1;

          end;

        end;

        hence thesis;

      end;

    end

    theorem :: SRINGS_1:8

    

     Thm1: for S be diff-finite-partition-closed Subset-Family of X, S1 be Element of S, T be finite Subset of S holds ex P be finite Subset of S st P is a_partition of (S1 \ ( union T))

    proof

      let S be diff-finite-partition-closed Subset-Family of X;

      let S1 be Element of S;

      let TT be finite Subset of S;

      consider T be FinSequence such that

       A0: TT = ( rng T) by FINSEQ_1: 52;

      reconsider T as FinSequence of S by A0, FINSEQ_1:def 4;

      defpred P[ FinSequence] means ex pa be finite Subset of S st pa is a_partition of (S1 \ ( union ( rng $1)));

      

       A1: for p be FinSequence of S, x be Element of S st P[p] holds P[(p ^ <*x*>)]

      proof

        let p be FinSequence of S;

        let x be Element of S;

        assume P[p];

        then

        consider pa be finite Subset of S such that

         A2: pa is a_partition of (S1 \ ( union ( rng p)));

        

         A3: (S1 \ ( union ( rng (p ^ <*x*>)))) = (S1 \ ( union (( rng p) \/ ( rng <*x*>)))) by FINSEQ_1: 31

        .= (S1 \ (( union ( rng p)) \/ ( union ( rng <*x*>)))) by ZFMISC_1: 78

        .= ((S1 \ ( union ( rng p))) \ ( Union <*x*>)) by XBOOLE_1: 41

        .= ((S1 \ ( union ( rng p))) \ ( union {x})) by FINSEQ_1: 38

        .= ((S1 \ ( union ( rng p))) \ x);

        ex pb be finite Subset of S st pb is a_partition of (S1 \ ( union ( rng (p ^ <*x*>))))

        proof

          defpred PP1[ set] means $1 is Element of S & ($1 \ x) is non empty & $1 in pa;

          defpred G[ object, object] means ex A1 be set st A1 = $1 & $1 is Element of S & $2 is finite Subset of S & (A1 \ x) is non empty & $1 in pa & $2 is a_partition of (A1 \ x);

          set XX1 = { s where s be Element of S : PP1[s] };

          set YY1 = { s where s be finite Subset of S : ex y be Element of S st PP1[y] & s is a_partition of (y \ x) };

          

           A4: for a be object st a in XX1 holds ex y be object st y in YY1 & G[a, y]

          proof

            let a be object;

            assume a in XX1;

            then

            consider s be Element of S such that

             A5: a = s & PP1[s];

            reconsider a as set by TARSKI: 1;

            consider aa be finite Subset of S such that

             A6: aa is a_partition of (a \ x) by A5, Defdiff;

            aa in YY1 & G[a, aa] by A5, A6;

            hence thesis;

          end;

          consider gg be Function such that

           A7: ( dom gg) = XX1 & ( rng gg) c= YY1 and

           A8: for x be object st x in XX1 holds G[x, (gg . x)] from FUNCT_1:sch 6( A4);

          

           A9: XX1 is finite

          proof

            XX1 c= pa

            proof

              let u be object;

              assume u in XX1;

              then

              consider s be Element of S such that

               A10: u = s & PP1[s];

              thus thesis by A10;

            end;

            hence thesis;

          end;

          ( Union gg) is finite Subset of S & ( Union gg) is a_partition of ((S1 \ ( union ( rng p))) \ x)

          proof

            

             A11: ( Union gg) is finite

            proof

              ( Union gg) is finite

              proof

                for zz be set st zz in ( rng gg) holds zz is finite

                proof

                  let zz be set;

                  assume zz in ( rng gg);

                  then

                  consider z0 be object such that

                   A12: z0 in XX1 & zz = (gg . z0) by A7, FUNCT_1:def 3;

                  ex A1 be set st A1 = z0 & z0 is Element of S & (gg . z0) is finite Subset of S & (A1 \ x) is non empty & z0 in pa & (gg . z0) is a_partition of (A1 \ x) by A8, A12;

                  hence thesis by A12;

                end;

                hence thesis by A7, A9, FINSET_1: 8, FINSET_1: 7;

              end;

              hence thesis;

            end;

            

             A13: ( Union gg) c= S

            proof

              let x be object;

              assume x in ( Union gg);

              then

              consider u be set such that

               A14: x in u and

               A15: u in ( rng gg) by TARSKI:def 4;

              consider u0 be object such that

               A16: u0 in XX1 & u = (gg . u0) by A7, A15, FUNCT_1:def 3;

               G[u0, (gg . u0)] by A8, A16;

              hence thesis by A14, A16;

            end;

            ( Union gg) is a_partition of ((S1 \ ( union ( rng p))) \ x)

            proof

              

               A17: ( Union gg) c= ( bool ((S1 \ ( union ( rng p))) \ x))

              proof

                let u be object;

                assume

                 A18: u in ( Union gg);

                reconsider u as set by TARSKI: 1;

                consider v be set such that

                 A19: u in v & v in ( rng gg) by A18, TARSKI:def 4;

                consider w be object such that

                 A20: w in ( dom gg) and

                 A21: (gg . w) = v by A19, FUNCT_1:def 3;

                reconsider w as set by TARSKI: 1;

                

                 A22: G[w, (gg . w)] by A7, A8, A20;

                then (w \ x) c= ((S1 \ ( union ( rng p))) \ x) by A2, XBOOLE_1: 33;

                then u c= ((S1 \ ( union ( rng p))) \ x) by A19, A21, A22, XBOOLE_1: 1;

                hence thesis;

              end;

              

               A23: ( union ( Union gg)) = ((S1 \ ( union ( rng p))) \ x)

              proof

                

                 A24: ( union ( Union gg)) c= ( union ( bool ((S1 \ ( union ( rng p))) \ x))) by A17, ZFMISC_1: 77;

                ((S1 \ ( Union p)) \ x) c= ( union ( Union gg))

                proof

                  let a be object;

                  assume

                   A25: a in ((S1 \ ( Union p)) \ x);

                  

                   A26: a in (( union pa) \ x) by A2, A25, EQREL_1:def 4;

                  then

                   A27: a in ( union pa) & not a in x by XBOOLE_0:def 5;

                  consider p11 be set such that

                   A28: a in p11 & p11 in pa by A26, TARSKI:def 4;

                  (p11 \ x) is non empty & p11 is Element of S & x is Element of S by A27, A28, XBOOLE_0:def 5;

                  then

                   A29: p11 in XX1 by A28;

                  then G[p11, (gg . p11)] by A8;

                  then ( union (gg . p11)) = (p11 \ x) by EQREL_1:def 4;

                  then a in ( union (gg . p11)) by A27, A28, XBOOLE_0:def 5;

                  then

                  consider d be set such that

                   A30: a in d & d in (gg . p11) by TARSKI:def 4;

                  a in d & d in (gg . p11) & (gg . p11) in ( rng gg) by A7, A29, A30, FUNCT_1: 3;

                  then a in d & d in ( union ( rng gg)) by TARSKI:def 4;

                  hence thesis by TARSKI:def 4;

                end;

                hence thesis by A24, ZFMISC_1: 81;

              end;

              for A be Subset of ((S1 \ ( union ( rng p))) \ x) st A in ( Union gg) holds A <> {} & for B be Subset of ((S1 \ ( union ( rng p))) \ x) st B in ( Union gg) holds A = B or (A misses B)

              proof

                let A be Subset of ((S1 \ ( union ( rng p))) \ x);

                assume

                 A31: A in ( Union gg);

                consider a0 be set such that

                 A32: A in a0 & a0 in ( rng gg) by A31, TARSKI:def 4;

                consider a1 be object such that

                 A33: a1 in XX1 & a0 = (gg . a1) by A7, A32, FUNCT_1:def 3;

                reconsider a1 as set by TARSKI: 1;

                A <> {} & for B be Subset of ((S1 \ ( union ( rng p))) \ x) st B in ( Union gg) holds A = B or (A misses B)

                proof

                  thus A <> {}

                  proof

                    assume

                     A34: A = {} ;

                     G[a1, (gg . a1)] by A8, A33;

                    hence thesis by A32, A33, A34;

                  end;

                  thus for B be Subset of ((S1 \ ( union ( rng p))) \ x) st B in ( Union gg) holds A = B or (A misses B)

                  proof

                    let B be Subset of ((S1 \ ( union ( rng p))) \ x);

                    assume B in ( Union gg);

                    then

                    consider x0 be set such that

                     A35: B in x0 & x0 in ( rng gg) by TARSKI:def 4;

                    consider y0 be object such that

                     A36: y0 in XX1 & (gg . y0) = x0 by A7, A35, FUNCT_1:def 3;

                    reconsider y0 as set by TARSKI: 1;

                    A = B or A misses B

                    proof

                      per cases ;

                        suppose

                         A37: a1 = y0;

                        then G[a1, (gg . a1)] by A8, A36;

                        hence thesis by A32, A33, A35, A36, A37, EQREL_1:def 4;

                      end;

                        suppose

                         A38: not a1 = y0;

                        consider sx be Element of S such that

                         A39: a1 = sx & PP1[sx] by A33;

                        consider sd be Element of S such that

                         A40: y0 = sd & PP1[sd] by A36;

                        

                         A41: (a1 \ x) misses (y0 \ x) by A2, A38, A39, A40, EQREL_1:def 4, XBOOLE_1: 64;

                        

                         A42: G[y0, (gg . y0)] by A8, A36;

                         G[a1, (gg . a1)] by A8, A33;

                        hence thesis by A32, A33, A35, A36, A41, A42, XBOOLE_1: 64;

                      end;

                    end;

                    hence thesis;

                  end;

                end;

                hence thesis;

              end;

              hence thesis by A17, A23, EQREL_1:def 4;

            end;

            hence thesis by A11, A13;

          end;

          hence thesis by A3;

        end;

        hence thesis;

      end;

      

       A44: P[( <*> S)]

      proof

        

         A45: S1 = {} implies ex pa be finite Subset of S st pa is a_partition of (S1 \ ( union ( rng {} )))

        proof

           {} is Subset of S by SUBSET_1: 1;

          hence thesis by EQREL_1: 45;

        end;

        S1 <> {} implies ex pa be finite Subset of S st pa is a_partition of (S1 \ ( union ( rng {} )))

        proof

          assume

           A47: S1 <> {} ;

          per cases ;

            suppose S is non empty;

            then

             A48: {S1} is Subset of S by SUBSET_1: 41;

             {S1} is a_partition of S1 by A47, EQREL_1: 39;

            hence thesis by A48, ZFMISC_1: 2;

          end;

            suppose S is empty;

            hence thesis by A47, SUBSET_1:def 1;

          end;

        end;

        hence thesis by A45;

      end;

      for p be FinSequence of S holds P[p] from FINSEQ_2:sch 2( A44, A1);

      then ex P be finite Subset of S st P is a_partition of (S1 \ ( Union T));

      hence thesis by A0;

    end;

    begin

    definition

      let X be set;

      let S be Subset-Family of X;

      :: SRINGS_1:def3

      attr S is diff-c=-finite-partition-closed means

      : Defdiff2: for S1,S2 be Element of S st S2 c= S1 holds ex x be finite Subset of S st x is a_partition of (S1 \ S2);

    end

    theorem :: SRINGS_1:9

    

     Thm2: for S be Subset-Family of X st S is diff-finite-partition-closed holds S is diff-c=-finite-partition-closed

    proof

      let S be Subset-Family of X;

      assume

       A1: S is diff-finite-partition-closed;

      let S1,S2 be Element of S;

      assume S2 c= S1;

      per cases ;

        suppose

         A2: (S1 \ S2) is empty;

         {} is finite Subset of S & {} is a_partition of {} by SUBSET_1: 1, EQREL_1: 45;

        hence thesis by A2;

      end;

        suppose (S1 \ S2) is non empty;

        then

        consider x be finite Subset of S such that

         A3: x is a_partition of (S1 \ S2) by A1;

        thus thesis by A3;

      end;

    end;

    registration

      let X;

      cluster diff-finite-partition-closed -> diff-c=-finite-partition-closed for Subset-Family of X;

      coherence by Thm2;

    end

    registration

      let X;

      cluster ( cobool X) -> diff-c=-finite-partition-closed;

      coherence ;

    end

    registration

      let X;

      cluster diff-c=-finite-partition-closed diff-finite-partition-closed cap-finite-partition-closed with_empty_element for Subset-Family of X;

      existence

      proof

        take ( cobool X);

        thus thesis;

      end;

    end

    theorem :: SRINGS_1:10

    for S be diff-finite-partition-closed Subset-Family of X holds { ( union x) where x be finite Subset of S : x is mutually-disjoint } is diff-closed

    proof

      let S be diff-finite-partition-closed Subset-Family of X;

      set Y = { ( union x) where x be finite Subset of S : x is mutually-disjoint };

      for A,B be set st A in Y & B in Y holds (A \ B) in Y

      proof

        let A,B be set;

        assume that

         A1: A in Y and

         A2: B in Y;

        consider a be finite Subset of S such that

         A3: A = ( union a) and

         A4: a is mutually-disjoint by A1;

        consider b be finite Subset of S such that

         A5: B = ( union b) and b is mutually-disjoint by A2;

        consider SFA be FinSequence such that

         A7: a = ( rng SFA) by FINSEQ_1: 52;

        consider SFB be FinSequence such that

         A8: b = ( rng SFB) by FINSEQ_1: 52;

        defpred F[ object, object] means ex A be set st A = $1 & $1 in a & $2 is a_partition of (A \ ( Union SFB));

        set XOUT = the set of all s where s be finite Subset of S;

        

         A12: for x be object st x in a holds ex y be object st y in XOUT & F[x, y]

        proof

          let x be object;

          assume

           A: x in a;

          reconsider x as set by TARSKI: 1;

          consider P be finite Subset of S such that

           B: P is a_partition of (x \ ( Union SFB)) by A, A8, Thm1;

          P in XOUT & F[x, P] by A, B;

          hence thesis;

        end;

        consider f be Function such that

         F1: ( dom f) = a & ( rng f) c= XOUT and

         F2: for x be object st x in a holds F[x, (f . x)] from FUNCT_1:sch 6( A12);

        

         V1: ( Union f) is finite Subset of S

        proof

          

           W1: ( Union f) is finite

          proof

            for x be set st x in ( rng f) holds x is finite

            proof

              let x be set;

              assume x in ( rng f);

              then x in XOUT by F1;

              then

              consider s be finite Subset of S such that

               V: x = s;

              thus thesis by V;

            end;

            hence thesis by F1, FINSET_1: 8, FINSET_1: 7;

          end;

          ( Union f) c= S

          proof

            let x be object;

            assume x in ( Union f);

            then

            consider y be set such that

             H: x in y & y in ( rng f) by TARSKI:def 4;

            y in XOUT by H, F1;

            then

            consider s be finite Subset of S such that

             I: y = s;

            thus thesis by H, I;

          end;

          hence thesis by W1;

        end;

        

         V1a: ( Union f) is a_partition of (( Union SFA) \ ( Union SFB))

        proof

          

           Z1: ( Union f) c= ( bool (( Union SFA) \ ( Union SFB)))

          proof

            let x be object;

            assume x in ( Union f);

            then

            consider y be set such that

             R1: x in y and

             R2: y in ( rng f) by TARSKI:def 4;

            consider x0 be object such that

             R3: x0 in ( dom f) and

             R4: y = (f . x0) by R2, FUNCT_1:def 3;

            reconsider x0 as set by TARSKI: 1;

            

             R5: F[x0, (f . x0)] by R3, F1, F2;

            (x0 \ ( Union SFB)) c= (( Union SFA) \ ( Union SFB)) by A7, R3, F1, ZFMISC_1: 74, XBOOLE_1: 33;

            then ( bool (x0 \ ( Union SFB))) c= ( bool (( Union SFA) \ ( Union SFB))) by ZFMISC_1: 67;

            then (f . x0) c= ( bool (( Union SFA) \ ( Union SFB))) by R5, XBOOLE_1: 1;

            hence thesis by R1, R4;

          end;

          

           Z2: ( union ( Union f)) = (( Union SFA) \ ( Union SFB))

          proof

            

             ZE: ( union ( Union f)) c= (( Union SFA) \ ( Union SFB))

            proof

              let x be object;

              assume

               A: x in ( union ( Union f));

              ( union ( Union f)) c= ( union ( bool (( Union SFA) \ ( Union SFB)))) by Z1, ZFMISC_1: 77;

              then x in ( union ( bool (( Union SFA) \ ( Union SFB)))) by A;

              hence thesis by ZFMISC_1: 81;

            end;

            (( Union SFA) \ ( Union SFB)) c= ( union ( Union f))

            proof

              let x be object;

              assume

               U1: x in (( Union SFA) \ ( Union SFB));

              consider y be set such that

               U2: x in y and

               U3: y in ( rng SFA) by U1, TARSKI:def 4;

              

               U4a: x in y & not x in ( Union SFB) by U2, U1, XBOOLE_0:def 5;

               F[y, (f . y)] by F2, U3, A7;

              then ( union (f . y)) = (y \ ( Union SFB)) by EQREL_1:def 4;

              then

               U6: x in ( union (f . y)) by U4a, XBOOLE_0:def 5;

              (f . y) in ( rng f) by F1, U3, A7, FUNCT_1:def 3;

              then ( union (f . y)) c= ( union ( Union f)) by ZFMISC_1: 74, ZFMISC_1: 77;

              hence thesis by U6;

            end;

            hence thesis by ZE;

          end;

          for m be Subset of (( Union SFA) \ ( Union SFB)) st m in ( Union f) holds m <> {} & for n be Subset of (( Union SFA) \ ( Union SFB)) st n in ( Union f) holds n = m or n misses m

          proof

            let m be Subset of (( Union SFA) \ ( Union SFB));

            assume

             L0: m in ( Union f);

            consider m0 be set such that

             L2: m in m0 and

             L3: m0 in ( rng f) by L0, TARSKI:def 4;

            consider m1 be object such that

             L4: m1 in a and

             L5: m0 = (f . m1) by L3, F1, FUNCT_1:def 3;

            reconsider m1 as set by TARSKI: 1;

            

             L6: F[m1, (f . m1)] by F2, L4;

            for n be Subset of (( Union SFA) \ ( Union SFB)) st n in ( Union f) holds n = m or n misses m

            proof

              let n be Subset of (( Union SFA) \ ( Union SFB));

              assume

               CL0: n in ( Union f);

              n = m or n misses m

              proof

                consider n0 be set such that

                 CL2: n in n0 and

                 CL3: n0 in ( rng f) by CL0, TARSKI:def 4;

                consider n1 be object such that

                 CL4: n1 in a and

                 CL5: n0 = (f . n1) by CL3, F1, FUNCT_1:def 3;

                reconsider n1 as set by TARSKI: 1;

                

                 CL6: F[n1, (f . n1)] by F2, CL4;

                per cases ;

                  suppose m1 = n1;

                  hence thesis by L2, L5, CL2, CL5, CL6, EQREL_1:def 4;

                end;

                  suppose

                   KKA: not m1 = n1;

                  (m1 \ ( Union SFB)) misses (n1 \ ( Union SFB)) by KKA, A4, L4, CL4, TAXONOM2:def 5, XBOOLE_1: 64;

                  hence thesis by L6, CL6, L2, L5, CL2, CL5, XBOOLE_1: 64;

                end;

              end;

              hence thesis;

            end;

            hence thesis by L2, L5, L6;

          end;

          hence thesis by Z1, Z2, EQREL_1:def 4;

        end;

        

         V2: ( Union f) is mutually-disjoint

        proof

          for n,m be set st n in ( Union f) & m in ( Union f) & n <> m holds n misses m by V1a, EQREL_1:def 4;

          hence thesis by TAXONOM2:def 5;

        end;

        (A \ B) = ( union ( Union f)) by V1a, A3, A5, A7, A8, EQREL_1:def 4;

        hence thesis by V1, V2;

      end;

      hence thesis;

    end;

    theorem :: SRINGS_1:11

    

     Thm5: for S be cap-finite-partition-closed diff-c=-finite-partition-closed Subset-Family of X holds (for A be Element of S, Q be finite Subset of S st ( union Q) c= A & Q is a_partition of ( union Q) holds ex R be finite Subset of S st ( union R) misses ( union Q) & (Q \/ R) is a_partition of A)

    proof

      let S be cap-finite-partition-closed diff-c=-finite-partition-closed Subset-Family of X;

      

       A1: (for A,B be Element of S holds ex P be finite Subset of S st P is a_partition of (A /\ B)) by Lem7;

      

       A2: (for C,D be Element of S st D c= C holds ex P be finite Subset of S st P is a_partition of (C \ D)) by Defdiff2;

      let A be Element of S;

      let Q be finite Subset of S;

      assume that

       A3: ( union Q) c= A and

       A4: Q is a_partition of ( union Q);

      per cases ;

        suppose

         A5: S is empty;

        then

         A6: A is empty by SUBSET_1:def 1;

        

         A7: ( union Q) misses ( union {} ) by ZFMISC_1: 2;

        

         A8: {} is finite Subset of {} & {} is a_partition of {} by SUBSET_1: 1, EQREL_1: 45;

        (Q \/ {} ) is a_partition of A by A5, A6, EQREL_1: 45;

        hence thesis by A5, A7, A8;

      end;

        suppose

         A9: not S is empty;

        per cases ;

          suppose

           A10: A is empty;

          

           A20: ( union Q) misses ( union {} ) by ZFMISC_1: 2;

          

           A21: {} is finite Subset of S & {} is a_partition of {} by XBOOLE_1: 2, EQREL_1: 45;

          (Q \/ {} ) is a_partition of A by A4, A10, A3;

          hence thesis by A21, A20;

        end;

          suppose not A is empty;

          hence thesis by A1, A2, A3, A4, A9, Lem6;

        end;

      end;

    end;

    theorem :: SRINGS_1:12

    

     Thm6: for S be diff-c=-finite-partition-closed cap-finite-partition-closed Subset-Family of X holds S is diff-finite-partition-closed

    proof

      let S be diff-c=-finite-partition-closed cap-finite-partition-closed Subset-Family of X;

      for S1,S2 be Element of S st (S1 \ S2) is non empty holds ex P0 be finite Subset of S st P0 is a_partition of (S1 \ S2)

      proof

        let S1,S2 be Element of S;

        assume (S1 \ S2) is non empty;

        consider P0 be finite Subset of S such that

         A1: P0 is a_partition of (S1 /\ S2) by Lem7;

        

         A2: ( union P0) c= S1

        proof

          let x be object;

          assume x in ( union P0);

          then

          consider x0 be set such that

           A3: x in x0 & x0 in P0 by TARSKI:def 4;

          (S1 /\ S2) c= S1 by XBOOLE_1: 17;

          then x0 c= S1 by A1, A3, XBOOLE_1: 1;

          hence thesis by A3;

        end;

        P0 is a_partition of ( union P0) by A1, EQREL_1:def 4;

        then

        consider R be finite Subset of S such that ( union R) misses ( union P0) and

         A4: (P0 \/ R) is a_partition of S1 by A2, Thm5;

        

         A5: (R /\ ( bool (S1 \ S2))) is finite Subset of S & (R /\ ( bool (S1 \ S2))) is a_partition of (S1 \ S2)

        proof

          

           A6: (R /\ ( bool (S1 \ S2))) is Subset-Family of (S1 \ S2) by XBOOLE_1: 17;

          

           A7: ( union (R /\ ( bool (S1 \ S2)))) = (S1 \ S2)

          proof

            

             A8: ( union (R /\ ( bool (S1 \ S2)))) c= (S1 \ S2)

            proof

              ( union (R /\ ( bool (S1 \ S2)))) c= ( union ( bool (S1 \ S2))) by XBOOLE_1: 17, ZFMISC_1: 77;

              hence thesis by ZFMISC_1: 81;

            end;

            (S1 \ S2) c= ( union (R /\ ( bool (S1 \ S2))))

            proof

              let x be object;

              assume

               A9: x in (S1 \ S2);

              then x in S1 & not x in S2 by XBOOLE_0:def 5;

              then x in ( union (P0 \/ R)) by A4, EQREL_1:def 4;

              then

              consider X0 be set such that

               A10: x in X0 and

               A11: X0 in (P0 \/ R) by TARSKI:def 4;

              

               A12: X0 in P0 implies X0 in ( bool S2)

              proof

                assume

                 A13: X0 in P0;

                (S1 /\ S2) c= S2 by XBOOLE_1: 17;

                then X0 c= S2 by A13, A1, XBOOLE_1: 1;

                hence thesis;

              end;

              X0 in (R /\ ( bool (S1 \ S2)))

              proof

                

                 A14: X0 in R by A12, A9, XBOOLE_0:def 5, A10, A11, XBOOLE_0:def 3;

                X0 c= (S1 \ S2)

                proof

                  assume not X0 c= (S1 \ S2);

                  then

                  consider xx be object such that

                   A15: xx in X0 and

                   A16: not xx in (S1 \ S2) by TARSKI:def 3;

                  xx in X0 & X0 in R by A12, A9, XBOOLE_0:def 5, A10, A11, XBOOLE_0:def 3, A15;

                  then

                   A17: xx in ( union R) by TARSKI:def 4;

                  ( union R) c= ( union (P0 \/ R)) by XBOOLE_1: 7, ZFMISC_1: 77;

                  then

                   A18: ( union R) c= S1 by A4, EQREL_1:def 4;

                  

                   A19: not xx in S1 or xx in S2 by A16, XBOOLE_0:def 5;

                  X0 in P0

                  proof

                    

                     A20: xx in (S1 /\ S2) by A18, A17, A19, XBOOLE_0:def 4;

                    ( union P0) = (S1 /\ S2) by A1, EQREL_1:def 4;

                    then

                    consider PP be set such that

                     A21: xx in PP and

                     A22: PP in P0 by A20, TARSKI:def 4;

                    

                     A23: xx in (PP /\ X0) by A21, A15, XBOOLE_0:def 4;

                    PP in (P0 \/ R) & X0 in (P0 \/ R) by A22, XBOOLE_0:def 3, A11;

                    hence thesis by A22, A4, A23, XBOOLE_0:def 7, EQREL_1:def 4;

                  end;

                  hence thesis by A10, A12, A9, XBOOLE_0:def 5;

                end;

                hence thesis by A14, XBOOLE_0:def 4;

              end;

              hence thesis by A10, TARSKI:def 4;

            end;

            hence thesis by A8;

          end;

          for A be Subset of (S1 \ S2) st A in (R /\ ( bool (S1 \ S2))) holds A <> {} & for B be Subset of (S1 \ S2) st B in (R /\ ( bool (S1 \ S2))) holds A = B or A misses B

          proof

            let A be Subset of (S1 \ S2) such that

             A24: A in (R /\ ( bool (S1 \ S2)));

            A in R by A24, XBOOLE_0:def 4;

            then

             A25: A in (P0 \/ R) by XBOOLE_0:def 3;

            now

              let B be Subset of (S1 \ S2) such that

               A26: B in (R /\ ( bool (S1 \ S2)));

              B in R by A26, XBOOLE_0:def 4;

              then B in (P0 \/ R) by XBOOLE_0:def 3;

              hence A = B or A misses B by A25, A4, EQREL_1:def 4;

            end;

            hence thesis by A25, A4;

          end;

          hence thesis by A6, A7, EQREL_1:def 4;

        end;

        thus thesis by A5;

      end;

      hence thesis;

    end;

    registration

      let X be set;

      cluster diff-c=-finite-partition-closed -> diff-finite-partition-closed for cap-finite-partition-closed Subset-Family of X;

      coherence by Thm6;

    end

    

     Lem9: for S be cap-finite-partition-closed diff-finite-partition-closed Subset-Family of X, SM,T be FinSequence of S holds ex P be finite Subset of S st P is a_partition of (( meet ( rng SM)) \ ( Union T))

    proof

      let S be cap-finite-partition-closed diff-finite-partition-closed Subset-Family of X;

      let SM be FinSequence of S;

      let T be FinSequence of S;

      defpred P[ FinSequence] means ex pa be finite Subset of S st pa is a_partition of (( meet ( rng $1)) \ ( union ( rng T)));

      

       A1: for p be FinSequence of S, x be Element of S st P[p] holds P[(p ^ <*x*>)]

      proof

        let p be FinSequence of S;

        let x be Element of S;

        assume P[p];

        then

        consider pa be finite Subset of S such that

         A2: pa is a_partition of (( meet ( rng p)) \ ( union ( rng T)));

        

         A3: (( meet ( rng (p ^ <*x*>))) \ ( union ( rng T))) = (( meet (( rng p) \/ ( rng <*x*>))) \ ( union ( rng T))) by FINSEQ_1: 31

        .= (( meet (( rng p) \/ {x})) \ ( union ( rng T))) by FINSEQ_1: 38;

        

         A4: ( rng p) <> {} implies (( meet (( rng p) \/ {x})) \ ( union ( rng T))) = ((( meet ( rng p)) \ ( union ( rng T))) /\ x)

        proof

          assume ( rng p) <> {} ;

          

          then (( meet (( rng p) \/ {x})) \ ( union ( rng T))) = ((( meet ( rng p)) /\ ( meet {x})) \ ( union ( rng T))) by SETFAM_1: 9

          .= ((( meet ( rng p)) /\ x) \ ( union ( rng T))) by SETFAM_1: 10

          .= ((( meet ( rng p)) \ ( union ( rng T))) /\ x) by XBOOLE_1: 49;

          hence thesis;

        end;

        ex pb be finite Subset of S st pb is a_partition of (( meet ( rng (p ^ <*x*>))) \ ( union ( rng T)))

        proof

          defpred PP1[ set] means $1 is Element of S & ($1 /\ x) is non empty & $1 in pa;

          defpred G[ object, object] means ex A1 be set st A1 = $1 & $1 is Element of S & $2 is finite Subset of S & (A1 /\ x) is non empty & $1 in pa & $2 is a_partition of (A1 /\ x);

          set XX1 = { s where s be Element of S : PP1[s] };

          set YY1 = { s where s be finite Subset of S : ex y be Element of S st PP1[y] & s is a_partition of (y /\ x) };

          

           A5: for a be object st a in XX1 holds ex y be object st y in YY1 & G[a, y]

          proof

            let a be object;

            assume a in XX1;

            then

            consider s be Element of S such that

             A6: a = s & PP1[s];

            reconsider a as set by TARSKI: 1;

            consider aa be finite Subset of S such that

             A7: aa is a_partition of (a /\ x) by A6, Defcap;

            aa in YY1 & G[a, aa] by A6, A7;

            hence thesis;

          end;

          consider gg be Function such that

           A8: ( dom gg) = XX1 & ( rng gg) c= YY1 and

           A9: for x be object st x in XX1 holds G[x, (gg . x)] from FUNCT_1:sch 6( A5);

          

           A10: XX1 is finite

          proof

            XX1 c= pa

            proof

              let u be object;

              assume u in XX1;

              then

              consider s be Element of S such that

               A11: u = s & PP1[s];

              thus thesis by A11;

            end;

            hence thesis;

          end;

          

           A12: ( Union gg) is finite Subset of S & ( Union gg) is a_partition of ((( meet ( rng p)) \ ( union ( rng T))) /\ x)

          proof

            

             A13: ( Union gg) is finite

            proof

              ( Union gg) is finite

              proof

                for zz be set st zz in ( rng gg) holds zz is finite

                proof

                  let zz be set;

                  assume zz in ( rng gg);

                  then

                  consider z0 be object such that

                   A14: z0 in XX1 & zz = (gg . z0) by FUNCT_1:def 3, A8;

                   G[z0, (gg . z0)] by A9, A14;

                  hence thesis by A14;

                end;

                hence thesis by A10, A8, FINSET_1: 8, FINSET_1: 7;

              end;

              hence thesis;

            end;

            

             A15: ( Union gg) c= S

            proof

              let x be object;

              assume x in ( Union gg);

              then

              consider u be set such that

               A16: x in u and

               A17: u in ( rng gg) by TARSKI:def 4;

              consider u0 be object such that

               A18: u0 in XX1 & u = (gg . u0) by A8, A17, FUNCT_1:def 3;

               G[u0, (gg . u0)] by A9, A18;

              hence thesis by A16, A18;

            end;

            ( Union gg) is a_partition of ((( meet ( rng p)) \ ( union ( rng T))) /\ x)

            proof

              

               A19: ( Union gg) c= ( bool ((( meet ( rng p)) \ ( union ( rng T))) /\ x))

              proof

                let u be object;

                assume

                 A20: u in ( Union gg);

                consider v be set such that

                 A21: u in v & v in ( rng gg) by TARSKI:def 4, A20;

                consider w be object such that

                 A22: w in ( dom gg) and

                 A23: (gg . w) = v by FUNCT_1:def 3, A21;

                reconsider u, w as set by TARSKI: 1;

                

                 A24: G[w, (gg . w)] by A22, A8, A9;

                then (w /\ x) c= ((( meet ( rng p)) \ ( union ( rng T))) /\ x) by A2, XBOOLE_1: 26;

                then u c= ((( meet ( rng p)) \ ( union ( rng T))) /\ x) by A23, A21, A24, XBOOLE_1: 1;

                hence thesis;

              end;

              

               A25: ( union ( Union gg)) = ((( meet ( rng p)) \ ( union ( rng T))) /\ x)

              proof

                

                 A26: ( union ( Union gg)) c= ( union ( bool ((( meet ( rng p)) \ ( union ( rng T))) /\ x))) by A19, ZFMISC_1: 77;

                ((( meet ( rng p)) \ ( union ( rng T))) /\ x) c= ( union ( Union gg))

                proof

                  let a be object;

                  assume a in ((( meet ( rng p)) \ ( union ( rng T))) /\ x);

                  then a in (( union pa) /\ x) by A2, EQREL_1:def 4;

                  then

                   A28: a in ( union pa) & a in x by XBOOLE_0:def 4;

                  then

                  consider p11 be set such that

                   A29: a in p11 & p11 in pa by TARSKI:def 4;

                  

                   A30: (p11 /\ x) is non empty & p11 is Element of S & x is Element of S by A28, A29, XBOOLE_0:def 4;

                  

                   A31: p11 in XX1 by A29, A30;

                  then G[p11, (gg . p11)] by A9;

                  then ( union (gg . p11)) = (p11 /\ x) by EQREL_1:def 4;

                  then a in ( union (gg . p11)) by A28, A29, XBOOLE_0:def 4;

                  then

                  consider d be set such that

                   A32: a in d & d in (gg . p11) by TARSKI:def 4;

                  a in d & d in (gg . p11) & (gg . p11) in ( rng gg) by A32, A8, A31, FUNCT_1: 3;

                  then a in d & d in ( union ( rng gg)) by TARSKI:def 4;

                  hence thesis by TARSKI:def 4;

                end;

                hence thesis by A26, ZFMISC_1: 81;

              end;

              for A be Subset of ((( meet ( rng p)) \ ( union ( rng T))) /\ x) st A in ( Union gg) holds A <> {} & for B be Subset of ((( meet ( rng p)) \ ( union ( rng T))) /\ x) st B in ( Union gg) holds A = B or (A misses B)

              proof

                let A be Subset of ((( meet ( rng p)) \ ( union ( rng T))) /\ x);

                assume A in ( Union gg);

                then

                consider a0 be set such that

                 A33: A in a0 & a0 in ( rng gg) by TARSKI:def 4;

                consider a1 be object such that

                 A34: a1 in XX1 & a0 = (gg . a1) by A33, A8, FUNCT_1:def 3;

                reconsider a1 as set by TARSKI: 1;

                A <> {} & for B be Subset of ((( meet ( rng p)) \ ( union ( rng T))) /\ x) st B in ( Union gg) holds A = B or (A misses B)

                proof

                  thus A <> {}

                  proof

                    assume

                     A35: A = {} ;

                     G[a1, (gg . a1)] by A9, A34;

                    hence thesis by A33, A34, A35;

                  end;

                  thus for B be Subset of ((( meet ( rng p)) \ ( union ( rng T))) /\ x) st B in ( Union gg) holds A = B or (A misses B)

                  proof

                    let B be Subset of ((( meet ( rng p)) \ ( union ( rng T))) /\ x);

                    assume B in ( Union gg);

                    then

                    consider x0 be set such that

                     A36: B in x0 & x0 in ( rng gg) by TARSKI:def 4;

                    consider y0 be object such that

                     A37: y0 in XX1 & (gg . y0) = x0 by A8, A36, FUNCT_1:def 3;

                    reconsider y0 as set by TARSKI: 1;

                    A = B or A misses B

                    proof

                      per cases ;

                        suppose

                         A38: a1 = y0;

                        then G[a1, (gg . a1)] by A9, A37;

                        hence thesis by EQREL_1:def 4, A36, A37, A33, A34, A38;

                      end;

                        suppose

                         A39: not a1 = y0;

                        consider sx be Element of S such that

                         A40: a1 = sx & PP1[sx] by A34;

                        consider sd be Element of S such that

                         A41: y0 = sd & PP1[sd] by A37;

                        a1 misses y0 & (a1 /\ x) c= a1 & (y0 /\ x) c= y0 by A40, A41, XBOOLE_1: 17, A39, A2, EQREL_1:def 4;

                        then

                         A42: (a1 /\ x) misses (y0 /\ x) by XBOOLE_1: 64;

                        

                         A43: G[y0, (gg . y0)] by A9, A37;

                         G[a1, (gg . a1)] by A9, A34;

                        hence thesis by A43, A36, A37, A33, A34, A42, XBOOLE_1: 64;

                      end;

                    end;

                    hence thesis;

                  end;

                end;

                hence thesis;

              end;

              hence thesis by EQREL_1:def 4, A19, A25;

            end;

            hence thesis by A13, A15;

          end;

          ( rng p) = {} implies ex ZZ be finite Subset of S st ZZ is a_partition of (( meet ( rng (p ^ <*x*>))) \ ( union ( rng T)))

          proof

            assume ( rng p) = {} ;

            then p = {} ;

            then (p ^ <*x*>) = <*x*> by FINSEQ_1: 34;

            then ( rng (p ^ <*x*>)) = {x} by FINSEQ_1: 39;

            then

             A44: (( meet ( rng (p ^ <*x*>))) \ ( union ( rng T))) = (x \ ( union ( rng T))) by SETFAM_1: 10;

            thus thesis by A44, Thm1;

          end;

          hence thesis by A4, A12, A3;

        end;

        hence thesis;

      end;

      

       A45: P[( <*> S)]

      proof

         {} is finite Subset of S & {} is a_partition of {} by SUBSET_1: 1, EQREL_1: 45;

        hence thesis by SETFAM_1: 1;

      end;

      for p be FinSequence of S holds P[p] from FINSEQ_2:sch 2( A45, A1);

      hence thesis;

    end;

    theorem :: SRINGS_1:13

    

     Thm3: for S be cap-finite-partition-closed diff-c=-finite-partition-closed Subset-Family of X, SM,T be finite Subset of S holds ex P be finite Subset of S st P is a_partition of (( meet SM) \ ( union T))

    proof

      let S be cap-finite-partition-closed diff-c=-finite-partition-closed Subset-Family of X;

      let SM,T be finite Subset of S;

      consider RSM be FinSequence such that

       A: SM = ( rng RSM) by FINSEQ_1: 52;

      consider RT be FinSequence such that

       B: T = ( rng RT) by FINSEQ_1: 52;

      

       C: RSM is FinSequence of S by A, FINSEQ_1:def 4;

      RT is FinSequence of S by B, FINSEQ_1:def 4;

      then

      consider P be finite Subset of S such that

       D: P is a_partition of (( meet ( rng RSM)) \ ( Union RT)) by C, Lem9;

      thus thesis by A, B, D;

    end;

    

     Lem10: for S be cap-finite-partition-closed diff-c=-finite-partition-closed Subset-Family of X, SM be FinSequence of S holds ex P be finite Subset of S st P is a_partition of ( Union SM) & for n be Nat st n in ( dom SM) holds (SM . n) = ( union { s where s be Element of S : s in P & s c= (SM . n) })

    proof

      let S be cap-finite-partition-closed diff-c=-finite-partition-closed Subset-Family of X;

      let SM be FinSequence of S;

      per cases ;

        suppose

         A0: S is empty;

         {} is finite Subset of S & {} is a_partition of ( Union SM) & for n be Nat st n in ( dom SM) holds (SM . n) = ( union { s where s be Element of S : s in {} & s c= (SM . n) }) by A0, ZFMISC_1: 2, EQREL_1: 45;

        hence thesis;

      end;

        suppose

         A1: S is non empty;

        defpred FF[ object, object] means ex A1 be set st A1 = $1 & A1 c= ( rng SM) & $2 is finite Subset of S & $2 is a_partition of (( meet A1) \ ( union (( rng SM) \ A1)));

        set FFIN = { s where s be Subset of S : s c= ( rng SM) };

        set FFOUT = { s where s be finite Subset of S : ex K be set st K c= ( rng SM) & s is a_partition of (( meet K) \ ( union (( rng SM) \ K))) };

        

         A5: for x be object st x in FFIN holds ex y be object st y in FFOUT & FF[x, y]

        proof

          let x be object;

          assume x in FFIN;

          then

          consider s0 be Subset of S such that

           A6: x = s0 & s0 c= ( rng SM);

          consider PK be finite Subset of S such that

           A7: PK is a_partition of (( meet s0) \ ( union (( rng SM) \ s0))) by A6, Thm3;

          PK in FFOUT by A6, A7;

          hence thesis by A6, A7;

        end;

        consider ff be Function such that

         A8: ( dom ff) = FFIN & ( rng ff) c= FFOUT and

         A9: for x be object st x in FFIN holds FF[x, (ff . x)] from FUNCT_1:sch 6( A5);

        set FFALL = ( Union ff);

        

         A10: for x be set st x in FFALL holds ex x0 be set st x0 in ( dom ff) & x in (ff . x0) & x0 c= ( rng SM) & (ff . x0) is finite Subset of S & (ff . x0) is a_partition of (( meet x0) \ ( union (( rng SM) \ x0)))

        proof

          let x be set;

          assume x in FFALL;

          then

          consider x0 be set such that

           A11: x in x0 & x0 in ( rng ff) by TARSKI:def 4;

          consider a0 be object such that

           A12: a0 in ( dom ff) & x0 = (ff . a0) by A11, FUNCT_1:def 3;

           FF[a0, (ff . a0)] by A8, A9, A12;

          hence thesis by A11, A12;

        end;

        

         A13: FFALL is finite Subset of S

        proof

          

           A14: FFALL c= S

          proof

            let x be object;

            assume x in FFALL;

            then

            consider x0 be set such that

             A15: x in x0 & x0 in ( rng ff) by TARSKI:def 4;

            consider a0 be object such that

             A16: a0 in ( dom ff) & x0 = (ff . a0) by A15, FUNCT_1:def 3;

             FF[a0, (ff . a0)] by A8, A9, A16;

            hence thesis by A15, A16;

          end;

          FFALL is finite

          proof

            

             A18: FFIN is finite

            proof

              FFIN c= ( bool ( rng SM))

              proof

                let x be object;

                assume x in FFIN;

                then

                consider s0 be Subset of S such that

                 A19: x = s0 & s0 c= ( rng SM);

                thus thesis by A19;

              end;

              hence thesis;

            end;

            ( Union ff) is finite

            proof

              for zz be set st zz in ( rng ff) holds zz is finite

              proof

                let zz be set;

                assume zz in ( rng ff);

                then

                consider z0 be object such that

                 A20: z0 in FFIN & zz = (ff . z0) by A8, FUNCT_1:def 3;

                 FF[z0, (ff . z0)] by A9, A20;

                hence thesis by A20;

              end;

              hence thesis by A8, A18, FINSET_1: 8, FINSET_1: 7;

            end;

            hence thesis;

          end;

          hence thesis by A14;

        end;

        

         A21: for x be set st x in FFALL holds x c= ( union ( rng SM))

        proof

          let x be set;

          assume x in FFALL;

          then

          consider x0 be set such that

           A22: x in x0 & x0 in ( rng ff) by TARSKI:def 4;

          consider a0 be object such that

           A23: a0 in ( dom ff) & x0 = (ff . a0) by A22, FUNCT_1:def 3;

          reconsider a0 as set by TARSKI: 1;

          

           A24: FF[a0, (ff . a0)] by A8, A9, A23;

          (( meet a0) \ ( union (( rng SM) \ a0))) c= ( union ( rng SM))

          proof

            let x be object;

            assume

             A25: x in (( meet a0) \ ( union (( rng SM) \ a0)));

            x in ( Union SM)

            proof

              per cases ;

                suppose a0 is empty;

                hence thesis by A25, SETFAM_1: 1;

              end;

                suppose not a0 is empty;

                then

                consider y0 be object such that

                 A26: y0 in a0;

                reconsider y0 as set by TARSKI: 1;

                x in y0 & y0 in ( rng SM) by A24, A25, A26, SETFAM_1:def 1;

                hence thesis by TARSKI:def 4;

              end;

            end;

            hence thesis;

          end;

          hence thesis by A22, A23, A24, XBOOLE_1: 1;

        end;

        

         A27: FFALL is a_partition of ( union ( rng SM))

        proof

          

           A28: FFALL c= ( bool ( union ( rng SM)))

          proof

            let x be object;

            assume

             B01: x in FFALL;

            reconsider x as set by TARSKI: 1;

            x c= ( Union SM) by B01, A21;

            hence thesis;

          end;

          

           A29: ( union FFALL) = ( union ( rng SM))

          proof

            

             A30: ( union FFALL) c= ( union ( rng SM))

            proof

              ( union FFALL) c= ( union ( bool ( union ( rng SM)))) by A28, ZFMISC_1: 77;

              hence thesis by ZFMISC_1: 81;

            end;

            ( union ( rng SM)) c= ( union FFALL)

            proof

              let x be object;

              assume

               A31: x in ( union ( rng SM));

              for x be set st x in ( union ( rng SM)) holds ex aa be set st aa in ( dom ff) & x in (( meet aa) \ ( union (( rng SM) \ aa)))

              proof

                let x be set;

                assume

                 A32: x in ( union ( rng SM));

                defpred PP[ FinSequence] means for x be set st x in ( union ( rng $1)) holds ex aa be Subset of S st aa c= ( rng $1) & x in (( meet aa) \ ( union (( rng $1) \ aa)));

                

                 A33: for p be FinSequence of S, t be Element of S st PP[p] holds PP[(p ^ <*t*>)]

                proof

                  let p be FinSequence of S;

                  let t be Element of S;

                  assume

                   A34: PP[p];

                  for x be set st x in ( union ( rng (p ^ <*t*>))) holds ex aa be Subset of S st aa c= ( rng (p ^ <*t*>)) & x in (( meet aa) \ ( union (( rng (p ^ <*t*>)) \ aa)))

                  proof

                    let x be set;

                    assume x in ( union ( rng (p ^ <*t*>)));

                    then x in ( union (( rng p) \/ ( rng <*t*>))) by FINSEQ_1: 31;

                    then x in (( Union p) \/ ( Union <*t*>)) by ZFMISC_1: 78;

                    then

                     A34a: x in (( Union p) \/ ( union {t})) by FINSEQ_1: 38;

                    

                     A36: (x in ( Union p) & x in t) implies ex aa be Subset of S st aa c= ( rng (p ^ <*t*>)) & x in (( meet aa) \ ( union (( rng (p ^ <*t*>)) \ aa)))

                    proof

                      assume

                       A37: x in ( Union p);

                      assume

                       A38: x in t;

                      consider aa1 be Subset of S such that

                       A39: aa1 c= ( rng p) & x in (( meet aa1) \ ( union (( rng p) \ aa1))) by A34, A37;

                      set aa = (aa1 \/ {t});

                      take aa;

                      

                       A40: {t} is Subset of S & aa1 is Subset of S by A1, SUBSET_1: 33;

                      

                       A41: aa c= ( rng (p ^ <*t*>))

                      proof

                        ( rng (p ^ <*t*>)) = (( rng p) \/ ( rng <*t*>)) by FINSEQ_1: 31;

                        then

                         A42: ( rng (p ^ <*t*>)) = (( rng p) \/ {t}) by FINSEQ_1: 38;

                        

                         A43: aa1 c= (( rng p) \/ {t}) by A39, XBOOLE_1: 10;

                         {t} c= (( rng p) \/ {t}) by XBOOLE_1: 7;

                        hence thesis by A42, A43, XBOOLE_1: 8;

                      end;

                      aa1 <> {} implies x in (( meet aa) \ ( union (( rng (p ^ <*t*>)) \ aa)))

                      proof

                        assume

                         A44: aa1 <> {} ;

                        x in ( meet aa1) & x in ( meet {t}) by A38, A39, SETFAM_1: 10;

                        then

                         A45: x in (( meet aa1) /\ ( meet {t})) by XBOOLE_0:def 4;

                        

                         A46: ( rng (p ^ <*t*>)) = (( rng p) \/ ( rng <*t*>)) by FINSEQ_1: 31;

                        ((( rng p) \/ {t}) \ (aa1 \/ {t})) = ((( rng p) \ (aa1 \/ {t})) \/ ( {t} \ (aa1 \/ {t}))) by XBOOLE_1: 42;

                        then ((( rng p) \/ {t}) \ (aa1 \/ {t})) = ((( rng p) \ (aa1 \/ {t})) \/ {} ) by XBOOLE_1: 46;

                        then (( rng (p ^ <*t*>)) \ aa) = (( rng p) \ (aa1 \/ {t})) by A46, FINSEQ_1: 38;

                        then (( rng (p ^ <*t*>)) \ aa) = ((( rng p) \ aa1) /\ (( rng p) \ {t})) by XBOOLE_1: 53;

                        then

                         A47: ( union (( rng (p ^ <*t*>)) \ aa)) c= ( union (( rng p) \ aa1)) by ZFMISC_1: 77, XBOOLE_1: 17;

                         not x in ( union (( rng (p ^ <*t*>)) \ aa)) & x in ( meet aa) by A39, A44, A45, A47, SETFAM_1: 9, XBOOLE_0:def 5;

                        hence thesis by XBOOLE_0:def 5;

                      end;

                      hence thesis by A39, A40, A41, XBOOLE_1: 8, SETFAM_1: 1;

                    end;

                    

                     A48: (x in ( Union p) & not x in t) implies ex aa be Subset of S st aa c= ( rng (p ^ <*t*>)) & x in (( meet aa) \ ( union (( rng (p ^ <*t*>)) \ aa)))

                    proof

                      assume

                       A49: x in ( Union p);

                      assume

                       A50: not x in t;

                      consider aa1 be Subset of S such that

                       A51: aa1 c= ( rng p) & x in (( meet aa1) \ ( union (( rng p) \ aa1))) by A34, A49;

                      set aa = (aa1 \ {t});

                      

                       A52: aa c= ( rng (p ^ <*t*>))

                      proof

                        

                         A53: ( rng (p ^ <*t*>)) = (( rng p) \/ ( rng <*t*>)) by FINSEQ_1: 31;

                        

                         A54: aa1 c= (( rng p) \/ {t}) by A51, XBOOLE_1: 10;

                        (aa1 \ {t}) c= aa1 by XBOOLE_1: 36;

                        then (aa1 \ {t}) c= (( rng p) \/ {t}) by A54, XBOOLE_1: 1;

                        hence thesis by A53, FINSEQ_1: 38;

                      end;

                      

                       A55: aa1 <> {} & (aa1 \ {t}) = {} implies ex aa be Subset of S st aa c= ( rng (p ^ <*t*>)) & x in (( meet aa) \ ( union (( rng (p ^ <*t*>)) \ aa)))

                      proof

                        assume

                         A56: aa1 <> {} ;

                        assume (aa1 \ {t}) = {} ;

                        then

                         A57: {t} = aa1 by A56, ZFMISC_1: 58;

                        set aa = aa1;

                        

                         A58: ( rng (p ^ <*t*>)) = (( rng p) \/ ( rng <*t*>)) by FINSEQ_1: 31

                        .= (( rng p) \/ {t}) by FINSEQ_1: 38;

                        

                         A59: ((( rng p) \/ {t}) \ {t}) = (( rng p) \ {t}) by XBOOLE_1: 40;

                        thus thesis by A51, A57, A58, A59, XBOOLE_1: 11;

                      end;

                      aa1 <> {} & (aa1 \ {t}) <> {} implies ex aa be Subset of S st aa c= ( rng (p ^ <*t*>)) & x in (( meet aa) \ ( union (( rng (p ^ <*t*>)) \ aa)))

                      proof

                        assume aa1 <> {} ;

                        assume

                         A60: (aa1 \ {t}) <> {} ;

                        

                         A61: for y be set st y in aa1 holds x in (y \ t)

                        proof

                          let y be set;

                          assume y in aa1;

                          then x in y & not x in t by A50, A51, SETFAM_1:def 1;

                          hence thesis by XBOOLE_0:def 5;

                        end;

                        for y be set st y in aa holds x in y

                        proof

                          let y be set;

                          assume y in aa;

                          then y in aa1 & not y in {t} by XBOOLE_0:def 5;

                          then x in (y \ t) & not y = t by A61, TARSKI:def 1;

                          hence thesis;

                        end;

                        then

                         A62: x in ( meet aa) by A60, SETFAM_1:def 1;

                        ( rng (p ^ <*t*>)) = (( rng p) \/ ( rng <*t*>)) by FINSEQ_1: 31;

                        then

                         A63: (( rng (p ^ <*t*>)) \ aa) = ((( rng p) \/ {t}) \ aa) by FINSEQ_1: 38;

                        

                         A64: (( {t} \ aa1) \/ {t}) = {t} by XBOOLE_1: 7, XBOOLE_1: 8;

                        (( rng (p ^ <*t*>)) \ aa) = ((( rng p) \ (aa1 \ {t})) \/ ( {t} \ (aa1 \ {t}))) by A63, XBOOLE_1: 42

                        .= ((( rng p) \ (aa1 \ {t})) \/ (( {t} \ aa1) \/ ( {t} /\ {t}))) by XBOOLE_1: 52

                        .= (((( rng p) \ aa1) \/ (( rng p) /\ {t})) \/ {t}) by A64, XBOOLE_1: 52

                        .= ((( rng p) \ aa1) \/ ((( rng p) /\ {t}) \/ {t})) by XBOOLE_1: 4

                        .= ((( rng p) \ aa1) \/ {t}) by XBOOLE_1: 22;

                        

                        then

                         A66: ( union (( rng (p ^ <*t*>)) \ aa)) = (( union (( rng p) \ aa1)) \/ ( union {t})) by ZFMISC_1: 78

                        .= (( union (( rng p) \ aa1)) \/ t);

                        

                         A67: not x in t & not x in ( union (( rng p) \ aa1)) implies not x in ( union (( rng (p ^ <*t*>)) \ aa)) by A66, XBOOLE_0:def 3;

                        x in (( meet aa) \ ( union (( rng (p ^ <*t*>)) \ aa))) by A50, A51, A62, A67, XBOOLE_0:def 5;

                        hence thesis by A52;

                      end;

                      then

                      consider aa be Subset of S such that

                       A68: aa c= ( rng (p ^ <*t*>)) & x in (( meet aa) \ ( union (( rng (p ^ <*t*>)) \ aa))) by A51, A55, SETFAM_1: 1;

                      thus thesis by A68;

                    end;

                    ( not x in ( Union p) & x in t) implies ex aa be Subset of S st aa c= ( rng (p ^ <*t*>)) & x in (( meet aa) \ ( union (( rng (p ^ <*t*>)) \ aa)))

                    proof

                      assume

                       A69: not x in ( Union p);

                      assume

                       A70: x in t;

                      

                       A71: ( rng (p ^ <*t*>)) = (( rng p) \/ ( rng <*t*>)) by FINSEQ_1: 31

                      .= (( rng p) \/ {t}) by FINSEQ_1: 38;

                      set aa = ( {t} \ ( rng p));

                      

                       A72: aa is Subset of S

                      proof

                         {t} is Subset of S & ( rng p) is Subset of S by A1, SUBSET_1: 33;

                        hence thesis by XBOOLE_1: 1;

                      end;

                      x in (( meet aa) \ ( union (( rng (p ^ <*t*>)) \ aa)))

                      proof

                        

                         A73: x in ( meet ( {t} \ ( rng p)))

                        proof

                          per cases ;

                            suppose

                             A74: ( {t} \ ( rng p)) <> {} ;

                            for y be set st y in ( {t} \ ( rng p)) holds x in y by A70, TARSKI:def 1;

                            hence thesis by A74, SETFAM_1:def 1;

                          end;

                            suppose ( {t} \ ( rng p)) = {} ;

                            then {t} is Subset of ( rng p) by SUBSET_1: 41, ZFMISC_1: 60;

                            then ( union {t}) c= ( Union p) by ZFMISC_1: 77;

                            hence thesis by A69, A70;

                          end;

                        end;

                         not x in ( union (( rng (p ^ <*t*>)) \ aa)) by A69, A71, Lem1;

                        hence thesis by A73, XBOOLE_0:def 5;

                      end;

                      hence thesis by A72, A71, XBOOLE_1: 10;

                    end;

                    hence thesis by A34a, A36, A48, XBOOLE_0:def 3;

                  end;

                  hence thesis;

                end;

                

                 A75: PP[( <*> S)] by ZFMISC_1: 2;

                for p be FinSequence of S holds PP[p] from FINSEQ_2:sch 2( A75, A33);

                then

                consider aa be Subset of S such that

                 A76: aa c= ( rng SM) & x in (( meet aa) \ ( union (( rng SM) \ aa))) by A32;

                take aa;

                thus thesis by A8, A76;

              end;

              then

              consider aa be set such that

               A77: aa in ( dom ff) & x in (( meet aa) \ ( union (( rng SM) \ aa))) by A31;

               FF[aa, (ff . aa)] by A8, A9, A77;

              then

               A78: x in ( union (ff . aa)) by A77, EQREL_1:def 4;

              (ff . aa) c= ( Union ff)

              proof

                let x be object;

                (ff . aa) in ( rng ff) by A77, FUNCT_1:def 3;

                hence thesis by TARSKI:def 4;

              end;

              then ( union (ff . aa)) c= ( union ( Union ff)) by ZFMISC_1: 77;

              hence thesis by A78;

            end;

            hence thesis by A30;

          end;

          for A be Subset of ( union ( rng SM)) st A in FFALL holds A <> {} & for B be Subset of ( union ( rng SM)) st B in FFALL holds A = B or A misses B

          proof

            let A be Subset of ( union ( rng SM));

            assume

             A80: A in FFALL;

            consider a0 be set such that

             A81: a0 in ( dom ff) & A in (ff . a0) & a0 c= ( rng SM) & (ff . a0) is finite Subset of S & (ff . a0) is a_partition of (( meet a0) \ ( union (( rng SM) \ a0))) by A10, A80;

            for B be Subset of ( union ( rng SM)) st B in FFALL holds A = B or A misses B

            proof

              let B be Subset of ( union ( rng SM));

              assume

               A82: B in FFALL;

              consider b0 be set such that

               A83: b0 in ( dom ff) & B in (ff . b0) & b0 c= ( rng SM) & (ff . b0) is finite Subset of S & (ff . b0) is a_partition of (( meet b0) \ ( union (( rng SM) \ b0))) by A10, A82;

              

               A84: a0 <> b0 implies (( meet b0) \ ( union (( rng SM) \ b0))) misses (( meet a0) \ ( union (( rng SM) \ a0)))

              proof

                assume

                 A85: a0 <> b0;

                ((( meet b0) \ ( union (( rng SM) \ b0))) /\ (( meet a0) \ ( union (( rng SM) \ a0)))) c= {}

                proof

                  let q be object;

                  assume

                   A87: q in ((( meet b0) \ ( union (( rng SM) \ b0))) /\ (( meet a0) \ ( union (( rng SM) \ a0))));

                  

                   A88: (q in (( meet b0) \ ( union (( rng SM) \ b0)))) & (q in (( meet a0) \ ( union (( rng SM) \ a0)))) by A87, XBOOLE_0:def 4;

                  then

                   A89: q in ( meet b0) & not q in ( union (( rng SM) \ b0)) & q in ( meet a0) & not q in ( union (( rng SM) \ a0)) by XBOOLE_0:def 5;

                  

                   A90: not (a0 c= b0) implies q in {}

                  proof

                    assume not a0 c= b0;

                    then

                    consider y0 be object such that

                     A91: y0 in a0 & not y0 in b0 by TARSKI:def 3;

                    reconsider y0 as set by TARSKI: 1;

                    

                     A92: q in y0 by A87, A91, SETFAM_1:def 1;

                    y0 in (( rng SM) \ b0) by A81, A91, XBOOLE_0:def 5;

                    hence thesis by A89, A92, TARSKI:def 4;

                  end;

                   not (b0 c= a0) implies q in {}

                  proof

                    assume not (b0 c= a0);

                    then

                    consider y0 be object such that

                     A99: y0 in b0 & not y0 in a0 by TARSKI:def 3;

                    reconsider y0 as set by TARSKI: 1;

                    

                     A100: q in y0 by A88, A99, SETFAM_1:def 1;

                    y0 in (( rng SM) \ a0) by A83, A99, XBOOLE_0:def 5;

                    hence thesis by A89, A100, TARSKI:def 4;

                  end;

                  hence thesis by A85, A90;

                end;

                hence thesis;

              end;

              thus thesis by A81, A83, A84, EQREL_1:def 4, XBOOLE_1: 64;

            end;

            hence thesis by A81;

          end;

          hence thesis by A28, A29, EQREL_1:def 4;

        end;

        for n be Nat st n in ( dom SM) holds (SM . n) = ( union { s where s be Element of S : s in FFALL & s c= (SM . n) })

        proof

          let n be Nat;

          assume

           A101: n in ( dom SM);

          

           A102: (SM . n) c= ( union { s where s be Element of S : s in FFALL & s c= (SM . n) })

          proof

            let x be object;

            assume

             A103: x in (SM . n);

            

             A104: ( union FFALL) = ( union ( rng SM)) by A27, EQREL_1:def 4;

            x in (SM . n) & (SM . n) in ( rng SM) by A101, A103, FUNCT_1:def 3;

            then

             A105: x in ( union ( rng SM)) by TARSKI:def 4;

            consider y0 be set such that

             A106: x in y0 & y0 in FFALL by A104, A105, TARSKI:def 4;

            consider d0 be set such that

             A107: d0 in ( dom ff) & y0 in (ff . d0) & d0 c= ( rng SM) & (ff . d0) is finite Subset of S & (ff . d0) is a_partition of (( meet d0) \ ( union (( rng SM) \ d0))) by A10, A106;

            y0 c= (SM . n)

            proof

              let u be object;

              assume u in y0;

              then

               A108: u in (( meet d0) \ ( union (( rng SM) \ d0))) by A107;

              

               A109: {(SM . n)} c= d0 implies u in (SM . n)

              proof

                assume

                 A110: {(SM . n)} c= d0;

                

                 A111: (SM . n) in {(SM . n)} by TARSKI:def 1;

                thus thesis by A108, A110, A111, SETFAM_1:def 1;

              end;

               not {(SM . n)} c= d0 implies u in (SM . n)

              proof

                assume not {(SM . n)} c= d0;

                then

                consider yy be object such that

                 A112: yy in {(SM . n)} & not yy in d0 by TARSKI:def 3;

                (SM . n) in ( rng SM) & not (SM . n) in d0 by A101, A112, FUNCT_1:def 3, TARSKI:def 1;

                then (SM . n) in (( rng SM) \ d0) by XBOOLE_0:def 5;

                then x in ( union (( rng SM) \ d0)) by A103, TARSKI:def 4;

                hence thesis by A106, A107, XBOOLE_0:def 5;

              end;

              hence thesis by A109;

            end;

            then x in y0 & y0 in { s where s be Element of S : s in FFALL & s c= (SM . n) } by A106, A107;

            hence thesis by TARSKI:def 4;

          end;

          ( union { s where s be Element of S : s in FFALL & s c= (SM . n) }) c= (SM . n)

          proof

            let x be object;

            assume x in ( union { s where s be Element of S : s in FFALL & s c= (SM . n) });

            then

            consider y be set such that

             A113: x in y & y in { s where s be Element of S : s in FFALL & s c= (SM . n) } by TARSKI:def 4;

            consider s0 be Element of S such that

             A114: y = s0 & s0 in FFALL & s0 c= (SM . n) by A113;

            thus thesis by A113, A114;

          end;

          hence thesis by A102;

        end;

        hence thesis by A13, A27;

      end;

    end;

    theorem :: SRINGS_1:14

    

     Thm87: for S be cap-finite-partition-closed diff-c=-finite-partition-closed Subset-Family of X, SM be finite Subset of S holds ex P be finite Subset of S st P is a_partition of ( union SM) & for Y be Element of SM holds Y = ( union { s where s be Element of S : s in P & s c= Y })

    proof

      let S be cap-finite-partition-closed diff-c=-finite-partition-closed Subset-Family of X;

      let SM be finite Subset of S;

      per cases ;

        suppose

         A1: SM is empty;

        for Y be Element of SM holds Y = ( union { s where s be Element of S : s in {} & s c= Y })

        proof

          let Y be Element of SM;

          

           A2: Y = {} by A1, SUBSET_1:def 1;

          ( union { s where s be Element of S : s in {} & s c= Y }) c= {}

          proof

            let x be object;

            assume x in ( union { s where s be Element of S : s in {} & s c= Y });

            then

            consider y be set such that x in y and

             A3: y in { s where s be Element of S : s in {} & s c= Y } by TARSKI:def 4;

            consider s be Element of S such that y = s and

             A4: s in {} and s c= Y by A3;

            thus thesis by A4;

          end;

          hence thesis by A2;

        end;

        hence thesis by A1, ZFMISC_1: 2, EQREL_1: 45;

      end;

        suppose

         A5: SM is non empty;

        consider FSM be FinSequence such that

         A6: SM = ( rng FSM) by FINSEQ_1: 52;

        FSM is FinSequence of S by A6, FINSEQ_1:def 4;

        then

        consider P be finite Subset of S such that

         A7: P is a_partition of ( Union FSM) and

         A8: for n be Nat st n in ( dom FSM) holds (FSM . n) = ( union { s where s be Element of S : s in P & s c= (FSM . n) }) by Lem10;

        for Y be Element of SM holds Y = ( union { s where s be Element of S : s in P & s c= Y })

        proof

          let Y be Element of SM;

          consider i be object such that

           A9: i in ( dom FSM) and

           A10: Y = (FSM . i) by A5, A6, FUNCT_1:def 3;

          thus Y c= ( union { s where s be Element of S : s in P & s c= Y }) by A9, A10, A8;

          thus ( union { s where s be Element of S : s in P & s c= Y }) c= Y by A9, A10, A8;

        end;

        hence thesis by A6, A7;

      end;

    end;

    

     Lem11: for S be cap-finite-partition-closed diff-finite-partition-closed Subset-Family of X, SM be Function of NATPLUS , S, n be NatPlus, x be set st x in (SM . n) holds ex n0 be NatPlus, np be Nat st n0 <= n & np = (n0 - 1) & x in ((SM . n0) \ ( Union (SM | ( Seg np))))

    proof

      let S be cap-finite-partition-closed diff-finite-partition-closed Subset-Family of X;

      let SM be Function of NATPLUS , S;

      let n be NatPlus;

      let x be set;

      assume

       A1: x in (SM . n);

      defpred Q[ Nat] means $1 is NatPlus & for y be set st y in (SM . $1) holds (ex n1,n0 be NatPlus, np be Nat st $1 = n1 & n0 <= n1 & np = (n0 - 1) & y in ((SM . n0) \ ( Union (SM | ( Seg np)))));

      

       A2: for k be Nat st k >= 1 & (for l be Nat st l >= 1 & l < k holds Q[l]) holds Q[k]

      proof

        let k be Nat;

        assume

         A3: k >= 1;

        assume

         A4: for l be Nat st l >= 1 & l < k holds Q[l];

        

         A5: k is NatPlus by A3, NAT_LAT:def 6;

        for y be set st y in (SM . k) holds (ex n1,n0 be NatPlus, np be Nat st k = n1 & n0 <= n1 & np = (n0 - 1) & y in ((SM . n0) \ ( Union (SM | ( Seg np)))))

        proof

          let y be set;

          assume

           A6: y in (SM . k);

          set k0 = (k - 1);

          reconsider k0 as Nat by A3, CHORD: 1;

          set n1 = k;

          

           A7: (SM . k) = (((SM . k) \ ( Union (SM | ( Seg k0)))) \/ ((SM . k) /\ ( Union (SM | ( Seg k0))))) by XBOOLE_1: 51;

          

           A8: y in ((SM . k) \ ( Union (SM | ( Seg k0)))) implies (ex n1,n0 be NatPlus, np be Nat st k = n1 & n0 <= n1 & np = (n0 - 1) & y in ((SM . n0) \ ( Union (SM | ( Seg np)))))

          proof

            assume

             A9: y in ((SM . k) \ ( Union (SM | ( Seg k0))));

            n1 is NatPlus by A3, NAT_LAT:def 6;

            hence thesis by A9;

          end;

          y in ((SM . k) /\ ( Union (SM | ( Seg k0)))) implies (ex n1,n0 be NatPlus, np be Nat st k = n1 & n0 <= n1 & np = (n0 - 1) & y in ((SM . n0) \ ( Union (SM | ( Seg np)))))

          proof

            assume y in ((SM . k) /\ ( Union (SM | ( Seg k0))));

            then y in ( Union (SM | ( Seg k0))) by XBOOLE_0:def 4;

            then

            consider yy be set such that

             A10: y in yy & yy in ( rng (SM | ( Seg k0))) by TARSKI:def 4;

            consider yyy be object such that

             A11: yyy in ( dom (SM | ( Seg k0))) & yy = ((SM | ( Seg k0)) . yyy) by A10, FUNCT_1:def 3;

            reconsider yyy as Nat by A11;

            

             A12: y in (SM . yyy) by A10, A11, FUNCT_1: 47;

            

             A13: 1 <= yyy & yyy <= k0 by A11, FINSEQ_1: 1;

            set kk = (k - 1);

            

             A14: kk is Nat by A3, CHORD: 1;

            yyy <= kk by A11, FINSEQ_1: 1;

            then yyy < ((k - 1) + 1) & k = ((k - 1) + 1) by A14, NAT_1: 13;

            then yyy >= 1 & yyy < k by A11, FINSEQ_1: 1;

            then

            consider n1,n0 be NatPlus, np be Nat such that

             A15: yyy = n1 & n0 <= n1 & np = (n0 - 1) & y in ((SM . n0) \ ( Union (SM | ( Seg np)))) by A4, A12;

            

             A16: n0 <= (k - 1) by A13, A15, XXREAL_0: 2;

            ((k - 1) + 1) = k;

            then

             A17: (k - 1) <= k by INT_1: 6;

            set n2 = k;

            thus thesis by A5, A15, A16, A17, XXREAL_0: 2;

          end;

          hence thesis by A6, A7, A8, XBOOLE_0:def 3;

        end;

        hence thesis by A3, NAT_LAT:def 6;

      end;

      

       A18: for k be Nat st k >= 1 holds Q[k] from NAT_1:sch 9( A2);

      for k be NatPlus holds Q[k]

      proof

        let k be NatPlus;

        k >= 1 by CHORD: 1;

        hence thesis by A18;

      end;

      then

      consider n1,n0 be NatPlus, np be Nat such that

       A19: n = n1 & n0 <= n1 & np = (n0 - 1) & x in ((SM . n0) \ ( Union (SM | ( Seg np)))) by A1;

      thus thesis by A19;

    end;

    theorem :: SRINGS_1:15

    

     Thm4: for S be cap-finite-partition-closed diff-c=-finite-partition-closed Subset-Family of X, SM be Function of NATPLUS , S holds ex P be countable Subset of S st P is a_partition of ( Union SM) & for n be NatPlus holds ( Union (SM | ( Seg n))) = ( union { s where s be Element of S : s in P & s c= ( Union (SM | ( Seg n))) })

    proof

      let S be cap-finite-partition-closed diff-c=-finite-partition-closed Subset-Family of X;

      let SM be Function of NATPLUS , S;

      per cases ;

        suppose

         A1: S = {} ;

        then

         A2: ( Union SM) = {} by ZFMISC_1: 2;

        set P = {} ;

        

         A3: P is finite Subset of S & P is a_partition of {} by SUBSET_1: 1, EQREL_1: 45;

        for n be NatPlus holds ( Union (SM | ( Seg n))) = ( union { s where s be Element of S : s in P & s c= ( Union (SM | ( Seg n))) })

        proof

          let n be NatPlus;

          thus ( Union (SM | ( Seg n))) c= ( union { s where s be Element of S : s in P & s c= ( Union (SM | ( Seg n))) })

          proof

            let x be object;

            assume x in ( Union (SM | ( Seg n)));

            hence thesis by A1, ZFMISC_1: 2;

          end;

          thus ( union { s where s be Element of S : s in P & s c= ( Union (SM | ( Seg n))) }) c= ( Union (SM | ( Seg n)))

          proof

            let x be object;

            assume x in ( union { s where s be Element of S : s in P & s c= ( Union (SM | ( Seg n))) });

            then

            consider y be set such that

             A5: x in y and

             A6: y in { s where s be Element of S : s in P & s c= ( Union (SM | ( Seg n))) } by TARSKI:def 4;

            consider s0 be Element of S such that

             A7: y = s0 and s0 in P and

             A8: s0 c= ( Union (SM | ( Seg n))) by A6;

            thus thesis by A5, A7, A8;

          end;

        end;

        hence thesis by A2, A3;

      end;

        suppose

         A9: not S = {} ;

        then

         A10: ( dom SM) = NATPLUS by FUNCT_2:def 1;

        

         A11: for x be NatPlus holds ex x1 be Nat st x1 = (x - 1) & ex Px be finite Subset of S st Px is a_partition of ((SM . x) \ ( Union (SM | ( Seg x1))))

        proof

          let x be NatPlus;

          set x1 = (x - 1);

          reconsider x1 as Nat by CHORD: 1;

          ( rng (SM | ( Seg x1))) is finite Subset of S;

          then ex P be finite Subset of S st P is a_partition of ((SM . x) \ ( Union (SM | ( Seg x1)))) by Thm1;

          hence thesis;

        end;

        defpred FH[ object, object] means ex x,xp be Nat st $1 = x & xp = (x - 1) & $2 is finite Subset of S & $2 is a_partition of ((SM . x) \ ( Union (SM | ( Seg xp))));

        

         A12: for n be object st n in NATPLUS holds ex y be object st y in ( bool S) & FH[n, y]

        proof

          let n be object;

          assume n in NATPLUS ;

          then

          consider n1 be NatPlus such that

           A13: n = n1;

          reconsider n as NatPlus by A13;

          consider x1 be Nat such that

           A14: x1 = (n - 1) & ex Px be finite Subset of S st Px is a_partition of ((SM . n) \ ( Union (SM | ( Seg x1)))) by A11;

          thus thesis by A14;

        end;

        consider fi be Function such that

         A15: ( dom fi) = NATPLUS & ( rng fi) c= ( bool S) and

         A16: for n be object st n in NATPLUS holds FH[n, (fi . n)] from FUNCT_1:sch 6( A12);

        

         A17: ( Union fi) is countable Subset of S & ( Union fi) is a_partition of ( Union SM)

        proof

          

           A18: ( Union fi) is countable Subset of S

          proof

            

             A19: ( Union fi) is countable

            proof

              for v be set st v in ( dom fi) holds (fi . v) is countable

              proof

                let v be set;

                assume v in ( dom fi);

                then FH[v, (fi . v)] by A15, A16;

                hence thesis;

              end;

              hence thesis by A15, CARD_4: 11;

            end;

            ( Union fi) c= S

            proof

              let u be object;

              assume u in ( Union fi);

              then ex v be set st u in v & v in ( rng fi) by TARSKI:def 4;

              hence thesis by A15;

            end;

            hence thesis by A19;

          end;

          

           A21: ( Union fi) is a_partition of ( Union SM)

          proof

            

             A22: ( Union fi) c= ( bool ( Union SM))

            proof

              let w be object;

              assume w in ( Union fi);

              then

              consider w0 be set such that

               A23: w in w0 & w0 in ( rng fi) by TARSKI:def 4;

              consider v0 be object such that

               A24: v0 in ( dom fi) & w0 = (fi . v0) by A23, FUNCT_1:def 3;

              reconsider w as set by TARSKI: 1;

              w c= ( union ( rng SM))

              proof

                let v be object;

                assume

                 A25: v in w;

                consider mx,mxp be Nat such that

                 A26: v0 = mx & mxp = (mx - 1) & (fi . v0) is finite Subset of S & (fi . v0) is a_partition of ((SM . mx) \ ( Union (SM | ( Seg mxp)))) by A15, A16, A24;

                

                 A27: v in ((SM . mx) \ ( Union (SM | ( Seg mxp)))) by A23, A24, A25, A26;

                mx in ( dom SM) by A9, A15, A24, A26, FUNCT_2:def 1;

                then (SM . mx) in ( rng SM) by FUNCT_1:def 3;

                hence thesis by A27, TARSKI:def 4;

              end;

              hence thesis;

            end;

            

             A28: ( union ( Union fi)) = ( Union SM)

            proof

              thus ( union ( Union fi)) c= ( Union SM)

              proof

                ( union ( Union fi)) c= ( union ( bool ( Union SM))) by A22, ZFMISC_1: 77;

                hence thesis by ZFMISC_1: 81;

              end;

              let v be object;

              assume v in ( Union SM);

              then

              consider v0 be set such that

               A30: v in v0 & v0 in ( rng SM) by TARSKI:def 4;

              consider v1 be object such that

               A31: v1 in ( dom SM) & v0 = (SM . v1) by A30, FUNCT_1:def 3;

              reconsider v1 as NatPlus by A31;

              consider n0 be NatPlus, np be Nat such that

               A32: n0 <= v1 & np = (n0 - 1) & v in ((SM . n0) \ ( Union (SM | ( Seg np)))) by A30, A31, Lem11;

               FH[n0, (fi . n0)] by A16;

              then

              consider x,xp be Nat such that

               A33: n0 = x & xp = (x - 1) & (fi . n0) is finite Subset of S & (fi . n0) is a_partition of ((SM . n0) \ ( Union (SM | ( Seg xp))));

              

               A34: ( union (fi . n0)) = ((SM . n0) \ ( Union (SM | ( Seg xp)))) by A33, EQREL_1:def 4;

              (fi . n0) c= ( Union fi)

              proof

                (fi . n0) in ( rng fi) by A15, FUNCT_1:def 3;

                hence thesis by ZFMISC_1: 74;

              end;

              then ( union (fi . n0)) c= ( union ( Union fi)) by ZFMISC_1: 77;

              hence thesis by A32, A33, A34;

            end;

            for A be Subset of ( Union SM) st A in ( Union fi) holds A <> {} & for B be Subset of ( Union SM) st B in ( Union fi) holds A = B or A misses B

            proof

              let A be Subset of ( Union SM);

              assume A in ( Union fi);

              then

              consider a0 be set such that

               A35: A in a0 & a0 in ( rng fi) by TARSKI:def 4;

              consider a1 be object such that

               A36: a1 in ( dom fi) & a0 = (fi . a1) by A35, FUNCT_1:def 3;

               FH[a1, (fi . a1)] by A15, A16, A36;

              then

              consider xa,xap be Nat such that

               A37: a1 = xa & xap = (xa - 1) & (fi . a1) is finite Subset of S & (fi . a1) is a_partition of ((SM . a1) \ ( Union (SM | ( Seg xap))));

              for B be Subset of ( Union SM) st B in ( Union fi) holds A = B or A misses B

              proof

                let B be Subset of ( Union SM);

                assume B in ( Union fi);

                then

                consider b0 be set such that

                 A38: B in b0 & b0 in ( rng fi) by TARSKI:def 4;

                consider b1 be object such that

                 A39: b1 in ( dom fi) & b0 = (fi . b1) by A38, FUNCT_1:def 3;

                 FH[b1, (fi . b1)] by A15, A16, A39;

                then

                consider xb,xbp be Nat such that

                 A40: b1 = xb & xbp = (xb - 1) & (fi . b1) is finite Subset of S & (fi . b1) is a_partition of ((SM . b1) \ ( Union (SM | ( Seg xbp))));

                 not a1 = b1 implies A = B or A misses B

                proof

                  assume

                   A41: not a1 = b1;

                  reconsider a1 as NatPlus by A15, A36;

                  reconsider b1 as NatPlus by A15, A39;

                  ((SM . a1) \ ( Union (SM | ( Seg xap)))) misses ((SM . b1) \ ( Union (SM | ( Seg xbp))))

                  proof

                    

                     A42: a1 < b1 implies ((SM . a1) \ ( Union (SM | ( Seg xap)))) misses ((SM . b1) \ ( Union (SM | ( Seg xbp))))

                    proof

                      assume

                       A43: a1 < b1;

                      assume not (((SM . a1) \ ( Union (SM | ( Seg xap)))) misses ((SM . b1) \ ( Union (SM | ( Seg xbp)))));

                      then

                      consider u be object such that

                       A44: u in (((SM . a1) \ ( Union (SM | ( Seg xap)))) /\ ((SM . b1) \ ( Union (SM | ( Seg xbp))))) by XBOOLE_0:def 1;

                      

                       A45: u in ((SM . a1) \ ( Union (SM | ( Seg xap)))) & u in ((SM . b1) \ ( Union (SM | ( Seg xbp)))) by A44, XBOOLE_0:def 4;

                      u in (SM . a1) implies u in ( Union (SM | ( Seg xbp)))

                      proof

                        assume

                         A46: u in (SM . a1);

                        

                         A47: 1 <= a1 by CHORD: 1;

                        xa < (xbp + 1) by A37, A40, A43;

                        then xa <= xbp by NAT_1: 13;

                        then

                         A48: xa in ( Seg xbp) by A37, A47;

                        

                         A49: a1 in ( dom (SM | ( Seg xbp))) by A10, A37, A48, RELAT_1: 57;

                        then ((SM | ( Seg xbp)) . a1) in ( rng (SM | ( Seg xbp))) by FUNCT_1:def 3;

                        then (SM . a1) in ( rng (SM | ( Seg xbp))) by A49, FUNCT_1: 47;

                        then (SM . a1) c= ( Union (SM | ( Seg xbp))) by ZFMISC_1: 74;

                        hence thesis by A46;

                      end;

                      hence thesis by A45, XBOOLE_0:def 5;

                    end;

                    b1 < a1 implies ((SM . a1) \ ( Union (SM | ( Seg xap)))) misses ((SM . b1) \ ( Union (SM | ( Seg xbp))))

                    proof

                      assume

                       A50: b1 < a1;

                      assume

                       A51: not (((SM . a1) \ ( Union (SM | ( Seg xap)))) misses ((SM . b1) \ ( Union (SM | ( Seg xbp)))));

                      

                       A52: not (((SM . a1) \ ( Union (SM | ( Seg xap)))) /\ ((SM . b1) \ ( Union (SM | ( Seg xbp))))) is empty by A51;

                      consider u be object such that

                       A53: u in (((SM . a1) \ ( Union (SM | ( Seg xap)))) /\ ((SM . b1) \ ( Union (SM | ( Seg xbp))))) by A52;

                      

                       A54: u in ((SM . a1) \ ( Union (SM | ( Seg xap)))) & u in ((SM . b1) \ ( Union (SM | ( Seg xbp)))) by A53, XBOOLE_0:def 4;

                      u in (SM . b1) implies u in ( Union (SM | ( Seg xap)))

                      proof

                        assume

                         A55: u in (SM . b1);

                        

                         A56: 1 <= b1 by CHORD: 1;

                        xb < (xap + 1) by A37, A40, A50;

                        then xb <= xap by NAT_1: 13;

                        then

                         A57: b1 in ( Seg xap) by A40, A56;

                        

                         A58: b1 in ( dom (SM | ( Seg xap))) by A10, A57, RELAT_1: 57;

                        then ((SM | ( Seg xap)) . b1) in ( rng (SM | ( Seg xap))) by FUNCT_1:def 3;

                        then (SM . b1) in ( rng (SM | ( Seg xap))) by A58, FUNCT_1: 47;

                        then (SM . b1) c= ( Union (SM | ( Seg xap))) by ZFMISC_1: 74;

                        hence thesis by A55;

                      end;

                      hence thesis by A54, XBOOLE_0:def 5;

                    end;

                    hence thesis by A41, A42, XXREAL_0: 1;

                  end;

                  hence thesis by A35, A36, A37, A38, A39, A40, XBOOLE_1: 64;

                end;

                hence thesis by A35, A36, A37, A38, A39, EQREL_1:def 4;

              end;

              hence thesis by A35, A36, A37;

            end;

            hence thesis by A22, A28, EQREL_1:def 4;

          end;

          thus thesis by A18, A21;

        end;

        

         A59: for l be Nat holds { s where s be Element of S : s in ( Union fi) & s c= ( Union (SM | ( Seg l))) } = (( Union fi) /\ ( bool ( Union (SM | ( Seg l)))))

        proof

          let l be Nat;

          

           A60: { s where s be Element of S : s in ( Union fi) & s c= ( Union (SM | ( Seg l))) } c= (( Union fi) /\ ( bool ( Union (SM | ( Seg l)))))

          proof

            let v be object;

            assume v in { s where s be Element of S : s in ( Union fi) & s c= ( Union (SM | ( Seg l))) };

            then

            consider s0 be Element of S such that

             A61: v = s0 & s0 in ( Union fi) & s0 c= ( Union (SM | ( Seg l)));

            thus thesis by A61, XBOOLE_0:def 4;

          end;

          (( Union fi) /\ ( bool ( Union (SM | ( Seg l))))) c= { s where s be Element of S : s in ( Union fi) & s c= ( Union (SM | ( Seg l))) }

          proof

            let v be object;

            assume

             A62: v in (( Union fi) /\ ( bool ( Union (SM | ( Seg l)))));

            then v in ( Union fi) & v in ( bool ( Union (SM | ( Seg l)))) by XBOOLE_0:def 4;

            then

            consider v0 be set such that

             A63: v in v0 & v0 in ( rng fi) by TARSKI:def 4;

            consider n0 be object such that

             A64: n0 in ( dom fi) & v0 = (fi . n0) by A63, FUNCT_1:def 3;

             FH[n0, (fi . n0)] by A15, A16, A64;

            then

            consider x,xp be Nat such that

             A65: n0 = x & xp = (x - 1) & (fi . n0) is finite Subset of S & (fi . n0) is a_partition of ((SM . n0) \ ( Union (SM | ( Seg xp))));

            v in S & v in ( Union fi) & v in ( bool ( Union (SM | ( Seg l)))) by A62, A63, A64, A65, XBOOLE_0:def 4;

            hence thesis;

          end;

          hence thesis by A60;

        end;

        for n be NatPlus holds ( Union (SM | ( Seg n))) = ( union { s where s be Element of S : s in ( Union fi) & s c= ( Union (SM | ( Seg n))) })

        proof

          let n be NatPlus;

          

           A66: ( Union (SM | ( Seg n))) c= ( Union SM) by ZFMISC_1: 77, RELAT_1: 70;

          ( Union (SM | ( Seg n))) = ( union (( Union fi) /\ ( bool ( Union (SM | ( Seg n))))))

          proof

            

             A67: ( Union (SM | ( Seg n))) c= ( union (( Union fi) /\ ( bool ( Union (SM | ( Seg n))))))

            proof

              let v be object;

              assume

               A68: v in ( Union (SM | ( Seg n)));

              then v in ( Union SM) by A66;

              then v in ( union ( Union fi)) by A17, EQREL_1:def 4;

              then

              consider v0 be set such that

               A69: v in v0 & v0 in ( Union fi) by TARSKI:def 4;

              v0 c= ( Union (SM | ( Seg n)))

              proof

                consider v1 be set such that

                 A70: v0 in v1 & v1 in ( rng fi) by A69, TARSKI:def 4;

                consider v2 be object such that

                 A71: v2 in ( dom fi) & v1 = (fi . v2) by A70, FUNCT_1:def 3;

                 FH[v2, (fi . v2)] by A15, A16, A71;

                then

                consider x2,x2p be Nat such that

                 A72: v2 = x2 & x2p = (x2 - 1) & (fi . v2) is finite Subset of S & (fi . v2) is a_partition of ((SM . v2) \ ( Union (SM | ( Seg x2p))));

                 not v in ( Union (SM | ( Seg x2p))) & v in ( Union (SM | ( Seg n))) by A68, A69, A70, A71, A72, XBOOLE_0:def 5;

                then

                 A73: v in (( Union (SM | ( Seg n))) \ ( Union (SM | ( Seg x2p)))) by XBOOLE_0:def 5;

                

                 A74: for n1,n2 be Nat st n1 <= n2 holds ( Union (SM | ( Seg n1))) c= ( Union (SM | ( Seg n2)))

                proof

                  let n1,n2 be Nat;

                  assume n1 <= n2;

                  then (SM | ( Seg n1)) c= (SM | ( Seg n2)) by FINSEQ_1: 5, RELAT_1: 75;

                  hence thesis by RELAT_1: 11, ZFMISC_1: 77;

                end;

                

                 A75: for n1,n2 be Nat st n1 <= n2 holds (( Union (SM | ( Seg n1))) \ ( Union (SM | ( Seg n2)))) = {}

                proof

                  let n1,n2 be Nat;

                  assume n1 <= n2;

                  then

                   A76: (SM | ( Seg n1)) c= (SM | ( Seg n2)) by FINSEQ_1: 5, RELAT_1: 75;

                  ( Union (SM | ( Seg n1))) c= ( Union (SM | ( Seg n2))) by A76, RELAT_1: 11, ZFMISC_1: 77;

                  hence thesis by XBOOLE_1: 37;

                end;

                ((x2 - 1) + 1) <= (n + 1) by XREAL_1: 6, A72, A73, A75;

                then

                 A77: x2 <= n or x2 = (n + 1) by NAT_1: 8;

                reconsider v2 as Nat by A72;

                

                 A78: v0 c= (SM . v2) by A70, A71, A72, XBOOLE_1: 1;

                for x be set, i,j be Nat st x c= (SM . i) & i <= j holds x c= ( Union (SM | ( Seg j)))

                proof

                  let x be set;

                  let i,j be Nat;

                  assume

                   A79: x c= (SM . i);

                  assume

                   A80: i <= j;

                  

                   A81: (SM . i) c= ( Union (SM | ( Seg i)))

                  proof

                    let y be object;

                    assume

                     A82: y in (SM . i);

                    per cases ;

                      suppose i is zero;

                      then not i in ( dom SM);

                      hence thesis by A82, FUNCT_1:def 2;

                    end;

                      suppose i is non zero;

                      then

                       A83: 1 <= i & i <= i by CHORD: 1;

                      ( Seg i) c= ( dom SM)

                      proof

                        let o be object;

                        assume

                         A84: o in ( Seg i);

                        then

                        reconsider o as Nat;

                        o is non zero by A84, FINSEQ_1: 1;

                        hence thesis by A10, NAT_LAT:def 6;

                      end;

                      then

                       A85: ( dom (SM | ( Seg i))) = ( Seg i) by RELAT_1: 62;

                      

                       A86: (SM . i) = ((SM | ( Seg i)) . i) by A83, A85, FINSEQ_1: 1, FUNCT_1: 47;

                      ((SM | ( Seg i)) . i) in ( rng (SM | ( Seg i))) by A83, A85, FINSEQ_1: 1, FUNCT_1: 3;

                      then (SM . i) c= ( Union (SM | ( Seg i))) by A86, ZFMISC_1: 74;

                      hence thesis by A82;

                    end;

                  end;

                  ( Union (SM | ( Seg i))) c= ( Union (SM | ( Seg j))) by A74, A80;

                  then (SM . i) c= ( Union (SM | ( Seg j))) by A81, XBOOLE_1: 1;

                  hence thesis by A79, XBOOLE_1: 1;

                end;

                hence thesis by A77, A72, A68, A69, A70, A71, A78, XBOOLE_0:def 5;

              end;

              then v in v0 & v0 in (( Union fi) /\ ( bool ( Union (SM | ( Seg n))))) by A69, XBOOLE_0:def 4;

              hence thesis by TARSKI:def 4;

            end;

            ( union (( Union fi) /\ ( bool ( Union (SM | ( Seg n)))))) c= ( Union (SM | ( Seg n)))

            proof

              

               A87: (( union ( Union fi)) /\ ( union ( bool ( Union (SM | ( Seg n)))))) = (( union ( Union fi)) /\ ( Union (SM | ( Seg n)))) by ZFMISC_1: 81;

              ( union ( Union fi)) = ( Union SM) by A17, EQREL_1:def 4;

              then ( union (( Union fi) /\ ( bool ( Union (SM | ( Seg n)))))) c= (( Union SM) /\ ( Union (SM | ( Seg n)))) by A87, ZFMISC_1: 79;

              hence thesis by A66, XBOOLE_1: 28;

            end;

            hence thesis by A67;

          end;

          hence thesis by A59;

        end;

        hence thesis by A17;

      end;

    end;

    begin

    definition

      let X be set;

      let S be Subset-Family of X;

      :: SRINGS_1:def4

      attr S is with_countable_Cover means ex XX be countable Subset of S st XX is Cover of X;

    end

    

     Lem6a: for X be set, S be Subset-Family of X, XX be Subset of S holds ( union XX) = X iff XX is Cover of X

    proof

      let X be set, S be Subset-Family of X, XX be Subset of S;

      XX is Subset-Family of X by XBOOLE_1: 1;

      hence thesis by SETFAM_1: 45;

    end;

    registration

      let X;

      cluster ( cobool X) -> with_countable_Cover;

      coherence

      proof

         {X} is countable Subset of ( cobool X) & ( union {X}) = X by ZFMISC_1: 7;

        hence thesis by Lem6a;

      end;

    end

    registration

      let X;

      cluster diff-c=-finite-partition-closed diff-finite-partition-closed cap-finite-partition-closed with_empty_element with_countable_Cover for Subset-Family of X;

      existence

      proof

        take ( cobool X);

        thus thesis;

      end;

    end

    theorem :: SRINGS_1:16

    for S be cap-finite-partition-closed diff-c=-finite-partition-closed Subset-Family of X st S is with_countable_Cover holds ex P be countable Subset of S st P is a_partition of X

    proof

      let S be cap-finite-partition-closed diff-c=-finite-partition-closed Subset-Family of X;

      assume S is with_countable_Cover;

      then

      consider XX be countable Subset of S such that

       A1: XX is Cover of X;

      per cases ;

        suppose

         C1: S is empty;

        X c= ( union XX) by A1, SETFAM_1:def 11;

        then

         C2: X is empty by C1, ZFMISC_1: 2;

        set P = {} ;

        P is countable Subset of S by SUBSET_1: 1;

        hence thesis by C2, EQREL_1: 45;

      end;

        suppose

         B0: S is non empty;

        

         A2: X c= ( union XX) by A1, SETFAM_1:def 11;

        per cases ;

          suppose

           A3: X is empty;

           {} is countable Subset of S by SUBSET_1: 1;

          hence thesis by A3, EQREL_1: 45;

        end;

          suppose

           A5: not X is empty;

          

           A6: ex g be Function of NATPLUS , S st ( rng g) = XX

          proof

            consider f be Function of omega , XX such that

             A7: ( rng f) = XX by A5, A2, ZFMISC_1: 2, CARD_3: 96;

            reconsider f as Function of NAT , XX;

            defpred G[ object, object] means $1 in NATPLUS & ex xx be Nat st (xx + 1) = $1 & $2 = (f . xx);

            

             A8: for x,y1,y2 be object st x in NATPLUS & G[x, y1] & G[x, y2] holds y1 = y2;

            

             A9: for x be object st x in NATPLUS holds ex y be object st G[x, y]

            proof

              let x be object;

              assume

               A10: x in NATPLUS ;

              then

              reconsider x as Nat;

              

               A11: (x - 1) is Nat by A10, CHORD: 1;

              ((x - 1) + 1) = x;

              then

              consider xx be Nat such that

               A12: (xx + 1) = x by A11;

              set y = (f . xx);

              x in NATPLUS & ex xx be Nat st (xx + 1) = x & y = (f . xx) by A10, A12;

              hence thesis;

            end;

            consider g be Function such that

             A13: ( dom g) = NATPLUS & for a be object st a in NATPLUS holds G[a, (g . a)] from FUNCT_1:sch 2( A8, A9);

            

             A14: ( rng g) = XX

            proof

              

               A15: ( rng g) c= XX

              proof

                let x be object;

                assume x in ( rng g);

                then

                consider y be object such that

                 A16: y in ( dom g) & x = (g . y) by FUNCT_1:def 3;

                consider xx be Nat such that

                 A17: (xx + 1) = y & (g . y) = (f . xx) by A13, A16;

                xx is Nat & ( dom f) = NAT by A5, A2, ZFMISC_1: 2, FUNCT_2:def 1;

                then xx in ( dom f) by ORDINAL1:def 12;

                then x in ( rng f) by A16, A17, FUNCT_1:def 3;

                hence thesis;

              end;

              XX c= ( rng g)

              proof

                let x be object;

                assume x in XX;

                then

                consider y be object such that

                 A18: y in ( dom f) & x = (f . y) by A7, FUNCT_1:def 3;

                reconsider y as Nat by A18;

                

                 A19: (y + 1) in ( dom g) & x = (f . y) by A13, A18, NAT_LAT:def 6;

                (g . (y + 1)) = (f . y)

                proof

                  consider xx be Nat such that

                   A20: (xx + 1) = (y + 1) & (g . (y + 1)) = (f . xx) by A13, A19;

                  thus thesis by A20;

                end;

                hence thesis by A19, FUNCT_1:def 3;

              end;

              hence thesis by A15;

            end;

            g is Function of NATPLUS , S by B0, A13, A14, FUNCT_2:def 1, RELSET_1: 4;

            hence thesis by A14;

          end;

          ex P be countable Subset of S st P is a_partition of X

          proof

            consider g be Function of NATPLUS , S such that

             A21: ( rng g) = XX by A6;

            consider P be countable Subset of S such that

             A22: P is a_partition of ( Union g) & for n be NatPlus holds ( Union (g | ( Seg n))) = ( union { s where s be Element of S : s in P & s c= ( Union (g | ( Seg n))) }) by Thm4;

            ( Union g) c= X

            proof

              let y be object;

              assume y in ( Union g);

              then

              consider z be set such that

               A24: y in z & z in ( rng g) by TARSKI:def 4;

              y in ( union S) by A24, TARSKI:def 4;

              hence thesis;

            end;

            then X = ( Union g) by A1, A21, SETFAM_1:def 11;

            hence thesis by A22;

          end;

          hence thesis;

        end;

      end;

    end;

    definition

      let X be set;

      mode semiring_of_sets of X is cap-finite-partition-closed diff-c=-finite-partition-closed with_empty_element Subset-Family of X;

    end

    

     LemPO: for S be Subset of X, A be Element of S holds ( union (( PARTITIONS A) /\ ( Fin S))) is with_non-empty_elements

    proof

      let S be Subset of X, A be Element of S;

      assume not ( union (( PARTITIONS A) /\ ( Fin S))) is with_non-empty_elements;

      then {} in ( union (( PARTITIONS A) /\ ( Fin S))) by SETFAM_1:def 8;

      then

      consider x be set such that

       A2: {} in x and

       A3: x in (( PARTITIONS A) /\ ( Fin S)) by TARSKI:def 4;

      x in ( PARTITIONS A) & x in ( Fin S) by A3, XBOOLE_0:def 4;

      then x is a_partition of A by PARTIT1:def 3;

      hence thesis by A2;

    end;

    theorem :: SRINGS_1:17

    

     ThmVAL0: for S be cap-finite-partition-closed Subset-Family of X, A be Element of S holds { x where x be Element of S : x in ( union (( PARTITIONS A) /\ ( Fin S))) } is cap-finite-partition-closed Subset-Family of A

    proof

      let S be cap-finite-partition-closed Subset-Family of X;

      let A be Element of S;

      set B = { x where x be Element of S : x in ( union (( PARTITIONS A) /\ ( Fin S))) };

      per cases ;

        suppose

         H0: A is empty;

        

         T1: B c= {}

        proof

          let t be object;

          assume t in B;

          then

          consider t0 be Element of S such that t = t0 and

           ZE2: t0 in ( union (( PARTITIONS A) /\ ( Fin S)));

          consider u0 be set such that

           ZE3: t0 in u0 and

           ZE4: u0 in (( PARTITIONS A) /\ ( Fin S)) by ZE2, TARSKI:def 4;

          u0 in { {} } by A4bis, ZE4, XBOOLE_0:def 4, H0;

          hence thesis by ZE3, TARSKI:def 1;

        end;

         {} is Subset-Family of {} by XBOOLE_1: 2;

        then

        reconsider B as Subset-Family of {} by T1;

        for a,b be Element of B st (a /\ b) is non empty holds ex P be finite Subset of B st P is a_partition of (a /\ b)

        proof

          let a,b be Element of B;

          assume

           VA: (a /\ b) is non empty;

          a = {} & b = {} by T1, SUBSET_1:def 1;

          hence thesis by VA;

        end;

        hence thesis by H0, Defcap;

      end;

        suppose

         H1: A is non empty;

        

         AA: B c= ( bool A)

        proof

          let x be object;

          assume x in B;

          then

          consider x0 be Element of S such that

           B1: x = x0 and

           B2: x0 in ( union (( PARTITIONS A) /\ ( Fin S)));

          consider x1 be set such that

           B3: x0 in x1 and

           B4: x1 in (( PARTITIONS A) /\ ( Fin S)) by B2, TARSKI:def 4;

          x1 in ( PARTITIONS A) by B4, XBOOLE_0:def 4;

          then x1 is a_partition of A by PARTIT1:def 3;

          hence x in ( bool A) by B1, B3;

        end;

        per cases ;

          suppose

           U0: B is empty;

          then

          reconsider B as Subset-Family of A by XBOOLE_1: 2;

          B is cap-finite-partition-closed by U0;

          hence thesis;

        end;

          suppose B is non empty;

          then

          reconsider B as non empty set;

          for x,y be Element of B st (x /\ y) is non empty holds ex P be finite Subset of B st P is a_partition of (x /\ y)

          proof

            let x,y be Element of B;

            assume

             V1: (x /\ y) is non empty;

            x in B;

            then

            consider x0 be Element of S such that

             A1: x = x0 and

             A2: x0 in ( union (( PARTITIONS A) /\ ( Fin S)));

            consider x1 be set such that

             C1: x0 in x1 and

             C2: x1 in (( PARTITIONS A) /\ ( Fin S)) by A2, TARSKI:def 4;

            y in B;

            then

            consider y0 be Element of S such that

             A3: y = y0 and

             A4: y0 in ( union (( PARTITIONS A) /\ ( Fin S)));

            consider y1 be set such that

             C3: y0 in y1 and

             C4: y1 in (( PARTITIONS A) /\ ( Fin S)) by A4, TARSKI:def 4;

            

             C4a: x1 in ( PARTITIONS A) & x1 in ( Fin S) & y1 in ( PARTITIONS A) & y1 in ( Fin S) by C2, C4, XBOOLE_0:def 4;

            then

             C5: x1 is a_partition of A & x1 is finite Subset of S & y1 is a_partition of A & y1 is finite Subset of S by PARTIT1:def 3, FINSUB_1:def 5;

            reconsider A as non empty set by H1;

            reconsider x1 as a_partition of A by C4a, PARTIT1:def 3;

            reconsider y1 as a_partition of A by C4a, PARTIT1:def 3;

            consider P be a_partition of A such that

             D1: P is finite Subset of S and

             D2: P '<' (x1 '/\' y1) by C5, ThmJ1;

            consider P1 be finite Subset of S such that

             F1: P1 is a_partition of (x /\ y) by A1, A3, V1, Defcap;

            P1 is finite Subset of B

            proof

              P1 c= B

              proof

                let d be object;

                assume

                 UP: d in P1;

                

                 UJ: x0 in x1 & x1 is a_partition of A by C1;

                

                 KK2: (x /\ y) c= A by A1, UJ, XBOOLE_1: 108;

                set PP = ({ p where p be Element of P : p misses (x /\ y) } \/ P1);

                

                 GH2: PP is finite Subset of S

                proof

                  

                   GHAA: PP c= (P \/ P1)

                  proof

                    let z be object;

                    assume z in PP;

                    then

                     UU: z in { p where p be Element of P : p misses (x /\ y) } or z in P1 by XBOOLE_0:def 3;

                    { p where p be Element of P : p misses (x /\ y) } c= P

                    proof

                      let a be object;

                      assume a in { p where p be Element of P : p misses (x /\ y) };

                      then

                      consider p be Element of P such that

                       UU2: a = p and p misses (x /\ y);

                      thus thesis by UU2;

                    end;

                    hence thesis by UU, XBOOLE_0:def 3;

                  end;

                  PP c= S

                  proof

                    let a be object;

                    assume a in PP;

                    then

                     GHAA: a in { p where p be Element of P : p misses (x /\ y) } or a in P1 by XBOOLE_0:def 3;

                    { p where p be Element of P : p misses (x /\ y) } c= S

                    proof

                      let b be object;

                      assume b in { p where p be Element of P : p misses (x /\ y) };

                      then

                      consider p be Element of P such that

                       GHC: b = p and p misses (x /\ y);

                      b in P by GHC;

                      hence thesis by D1;

                    end;

                    hence thesis by GHAA;

                  end;

                  hence thesis by GHAA, D1;

                end;

                PP is a_partition of A

                proof

                  

                   FD1: PP c= ( bool A)

                  proof

                    let z be object;

                    assume z in PP;

                    then

                     O1: z in { p where p be Element of P : p misses (x /\ y) } or z in P1 by XBOOLE_0:def 3;

                    

                     O2: { p where p be Element of P : p misses (x /\ y) } c= ( bool A)

                    proof

                      let t be object;

                      assume t in { p where p be Element of P : p misses (x /\ y) };

                      then

                      consider t0 be Element of P such that

                       O3: t = t0 & t0 misses (x /\ y);

                      thus thesis by O3;

                    end;

                    P1 c= ( bool A)

                    proof

                      let t be object;

                      assume

                       X1: t in P1;

                      ( bool (x /\ y)) c= ( bool A)

                      proof

                        

                         X3: x in B;

                        (x /\ y) c= x by XBOOLE_1: 17;

                        then (x /\ y) c= A by AA, X3, XBOOLE_1: 1;

                        hence thesis by ZFMISC_1: 67;

                      end;

                      then P1 c= ( bool A) by F1, XBOOLE_1: 1;

                      hence thesis by X1;

                    end;

                    hence thesis by O1, O2;

                  end;

                  

                   FD2: ( union PP) = A

                  proof

                    thus ( union PP) c= A

                    proof

                      let a be object;

                      assume

                       S0: a in ( union PP);

                      

                       S1: ( union PP) = (( union { p where p be Element of P : p misses (x /\ y) }) \/ ( union P1)) by ZFMISC_1: 78;

                      

                       S5: ( union P1) c= A by KK2, F1, EQREL_1:def 4;

                      ( union { p where p be Element of P : p misses (x /\ y) }) c= A

                      proof

                        

                         S5a: { p where p be Element of P : p misses (x /\ y) } c= P

                        proof

                          let a be object;

                          assume a in { p where p be Element of P : p misses (x /\ y) };

                          then

                          consider b be Element of P such that

                           S6: a = b and b misses (x /\ y);

                          thus thesis by S6;

                        end;

                        ( union P) = A by EQREL_1:def 4;

                        hence thesis by S5a, ZFMISC_1: 77;

                      end;

                      then (( union { p where p be Element of P : p misses (x /\ y) }) \/ ( union P1)) c= A by S5, XBOOLE_1: 8;

                      hence thesis by S0, S1;

                    end;

                    let a be object;

                    assume

                     PO0: a in A;

                    per cases ;

                      suppose

                       PO1: a in (x /\ y);

                      a in ( union P1) by PO1, F1, EQREL_1:def 4;

                      then a in (( union P1) \/ ( union { p where p be Element of P : p misses (x /\ y) })) by XBOOLE_1: 7, TARSKI:def 3;

                      hence thesis by ZFMISC_1: 78;

                    end;

                      suppose

                       I0: not a in (x /\ y);

                      ( union P) = A by EQREL_1:def 4;

                      then

                      consider b be set such that

                       I1: a in b and

                       I2: b in P by PO0, TARSKI:def 4;

                      consider u be set such that

                       W1: u in (x1 '/\' y1) and

                       W2: b c= u by I2, D2, SETFAM_1:def 2;

                      consider xx1,yy1 be set such that

                       W3: xx1 in x1 & yy1 in y1 and

                       W4: u = (xx1 /\ yy1) by W1, SETFAM_1:def 5;

                      

                       W5W: (xx1 /\ yy1) misses (x /\ y)

                      proof

                        assume not (xx1 /\ yy1) misses (x /\ y);

                        then

                        consider i be object such that

                         W5A: i in ((xx1 /\ yy1) /\ (x /\ y)) by XBOOLE_0:def 1;

                        i in (xx1 /\ yy1) & i in (x /\ y) by W5A, XBOOLE_0:def 4;

                        then i in xx1 & i in yy1 & i in x & i in y by XBOOLE_0:def 4;

                        then i in (xx1 /\ x) & i in (yy1 /\ y) by XBOOLE_0:def 4;

                        then xx1 = x & yy1 = y by A1, C1, A3, C3, W3, EQREL_1:def 4, XBOOLE_0:def 7;

                        hence thesis by I0, I1, W2, W4;

                      end;

                      b misses (x /\ y)

                      proof

                        assume not b misses (x /\ y);

                        then

                        consider b0 be object such that

                         W6: b0 in (b /\ (x /\ y)) by XBOOLE_0:def 1;

                        b0 in b & b0 in (x /\ y) by W6, XBOOLE_0:def 4;

                        hence thesis by W5W, W2, W4, XBOOLE_0:def 4;

                      end;

                      then b in { p where p be Element of P : p misses (x /\ y) } by I2;

                      then a in ( union { p where p be Element of P : p misses (x /\ y) }) by I1, TARSKI:def 4;

                      then a in (( union { p where p be Element of P : p misses (x /\ y) }) \/ ( union P1)) by XBOOLE_1: 7, TARSKI:def 3;

                      hence thesis by ZFMISC_1: 78;

                    end;

                  end;

                  for a be Subset of A st a in PP holds a <> {} & for b be Subset of A st b in PP holds a = b or a misses b

                  proof

                    let a be Subset of A;

                    assume a in PP;

                    then

                     DF1: a in { p where p be Element of P : p misses (x /\ y) } or a in P1 by XBOOLE_0:def 3;

                    

                     DF1A: { p where p be Element of P : p misses (x /\ y) } c= P

                    proof

                      let a be object;

                      assume a in { p where p be Element of P : p misses (x /\ y) };

                      then

                      consider p be Element of P such that

                       UU2: a = p and p misses (x /\ y);

                      thus thesis by UU2;

                    end;

                    for b be Subset of A st b in PP holds a = b or a misses b

                    proof

                      let b be Subset of A;

                      assume b in PP;

                      then

                       DF5: b in { p where p be Element of P : p misses (x /\ y) } or b in P1 by XBOOLE_0:def 3;

                      

                       DF7A: a in { p where p be Element of P : p misses (x /\ y) } & b in P1 implies a misses b

                      proof

                        assume that

                         QW1: a in { p where p be Element of P : p misses (x /\ y) } and

                         QW2: b in P1;

                        consider a0 be Element of P such that

                         QW3: a = a0 & a0 misses (x /\ y) by QW1;

                        thus thesis by QW3, QW2, F1, XBOOLE_1: 63;

                      end;

                      b in { p where p be Element of P : p misses (x /\ y) } & a in P1 implies a misses b

                      proof

                        assume that

                         QW1: b in { p where p be Element of P : p misses (x /\ y) } and

                         QW2: a in P1;

                        consider b0 be Element of P such that

                         QW3: b = b0 & b0 misses (x /\ y) by QW1;

                        thus thesis by QW3, QW2, F1, XBOOLE_1: 63;

                      end;

                      hence thesis by DF1, DF5, DF1A, DF7A, F1, EQREL_1:def 4;

                    end;

                    hence thesis by F1, DF1A, DF1;

                  end;

                  hence thesis by FD1, FD2, EQREL_1:def 4;

                end;

                then d in PP & PP in ( PARTITIONS A) & PP in ( Fin S) by UP, XBOOLE_0:def 3, GH2, PARTIT1:def 3, FINSUB_1:def 5;

                then d in PP & PP in (( PARTITIONS A) /\ ( Fin S)) by XBOOLE_0:def 4;

                then d in ( union (( PARTITIONS A) /\ ( Fin S))) by TARSKI:def 4;

                hence thesis by UP;

              end;

              hence thesis;

            end;

            hence thesis by F1;

          end;

          hence thesis by AA, Defcap;

        end;

      end;

    end;

    theorem :: SRINGS_1:18

    

     ThmVAL2: for S be cap-finite-partition-closed Subset-Family of X, A be Element of S holds { x where x be Element of S : x in ( union (( PARTITIONS A) /\ ( Fin S))) } is diff-c=-finite-partition-closed Subset-Family of A

    proof

      let S be cap-finite-partition-closed Subset-Family of X, A be Element of S;

      set B = { x where x be Element of S : x in ( union (( PARTITIONS A) /\ ( Fin S))) };

      per cases ;

        suppose

         H0: A is empty;

        

         T1: B c= {}

        proof

          let t be object;

          assume t in B;

          then

          consider t0 be Element of S such that t = t0 and

           ZE2: t0 in ( union (( PARTITIONS A) /\ ( Fin S)));

          consider u0 be set such that

           ZE3: t0 in u0 and

           ZE4: u0 in (( PARTITIONS A) /\ ( Fin S)) by ZE2, TARSKI:def 4;

          u0 in ( PARTITIONS A) by ZE4, XBOOLE_0:def 4;

          hence thesis by H0, ZE3, A4bis, TARSKI:def 1;

        end;

         {} is Subset-Family of {} by XBOOLE_1: 2;

        then

        reconsider B as Subset-Family of {} by T1;

        for a,b be Element of B st (a \ b) is non empty holds ex P be finite Subset of B st P is a_partition of (a \ b) by T1, SUBSET_1:def 1;

        then B is diff-finite-partition-closed;

        hence thesis by H0;

      end;

        suppose

         H1: A is non empty;

        

         AA: B c= ( bool A)

        proof

          let x be object;

          assume x in B;

          then

          consider x0 be Element of S such that

           B1: x = x0 and

           B2: x0 in ( union (( PARTITIONS A) /\ ( Fin S)));

          consider x1 be set such that

           B3: x0 in x1 and

           B4: x1 in (( PARTITIONS A) /\ ( Fin S)) by B2, TARSKI:def 4;

          x1 in ( PARTITIONS A) & x1 in ( Fin S) by B4, XBOOLE_0:def 4;

          then x1 is a_partition of A by PARTIT1:def 3;

          hence x in ( bool A) by B1, B3;

        end;

        per cases ;

          suppose

           U0: B is empty;

          then

          reconsider B as Subset-Family of A by XBOOLE_1: 2;

          for S1,S2 be Element of B st (S1 \ S2) is non empty holds ex P be finite Subset of B st P is a_partition of (S1 \ S2) by U0, SUBSET_1:def 1;

          then B is diff-finite-partition-closed;

          hence thesis;

        end;

          suppose B is non empty;

          then

          reconsider B as non empty set;

          for x,y be Element of B st y c= x holds ex P be finite Subset of B st P is a_partition of (x \ y)

          proof

            let x,y be Element of B;

            assume y c= x;

            x in B;

            then

            consider x0 be Element of S such that

             A1: x = x0 and

             A2: x0 in ( union (( PARTITIONS A) /\ ( Fin S)));

            consider x1 be set such that

             C1: x0 in x1 and

             C2: x1 in (( PARTITIONS A) /\ ( Fin S)) by A2, TARSKI:def 4;

            y in B;

            then

            consider y0 be Element of S such that

             A3: y = y0 and

             A4: y0 in ( union (( PARTITIONS A) /\ ( Fin S)));

            consider y1 be set such that

             C3: y0 in y1 and

             C4: y1 in (( PARTITIONS A) /\ ( Fin S)) by A4, TARSKI:def 4;

            

             C4A: x1 in ( PARTITIONS A) & x1 in ( Fin S) & y1 in ( PARTITIONS A) & y1 in ( Fin S) by C2, C4, XBOOLE_0:def 4;

            then

             C5: x1 is a_partition of A & x1 is finite Subset of S & y1 is a_partition of A & y1 is finite Subset of S by PARTIT1:def 3, FINSUB_1:def 5;

            reconsider A as non empty set by H1;

            reconsider x1, y1 as a_partition of A by C4A, PARTIT1:def 3;

            consider P be a_partition of A such that

             D1: P is finite Subset of S and

             D2: P '<' (x1 '/\' y1) by C5, ThmJ1;

            set P1 = { p where p be Element of P : p is Subset of x & p misses y };

            

             T1: P1 is finite Subset of B

            proof

              

               T1A: P1 is finite

              proof

                P1 c= P

                proof

                  let a be object;

                  assume a in P1;

                  then ex p be Element of P st a = p & p is Subset of x & p misses y;

                  hence thesis;

                end;

                hence thesis by D1;

              end;

              P1 c= B

              proof

                let a be object;

                assume a in P1;

                then

                consider p be Element of P such that

                 EZ2: a = p and p is Subset of x and p misses y;

                a in P & P in ( PARTITIONS A) & P in ( Fin S) by EZ2, D1, FINSUB_1:def 5, PARTIT1:def 3;

                then a in P & P in (( PARTITIONS A) /\ ( Fin S)) by XBOOLE_0:def 4;

                then

                 EZ6: a in ( union (( PARTITIONS A) /\ ( Fin S))) by TARSKI:def 4;

                a in P by EZ2;

                hence thesis by D1, EZ6;

              end;

              hence thesis by T1A;

            end;

            P1 is a_partition of (x \ y)

            proof

              

               Y1: P1 c= ( bool (x \ y))

              proof

                let a be object;

                assume a in P1;

                then

                consider p be Element of P such that

                 EZ7: a = p and

                 EZ8: p is Subset of x and

                 EZ9: p misses y;

                reconsider a as set by TARSKI: 1;

                a c= (x \ y) by EZ7, EZ8, EZ9, XBOOLE_1: 86;

                hence thesis;

              end;

              

               Y2: ( union P1) = (x \ y)

              proof

                thus ( union P1) c= (x \ y)

                proof

                  let a be object;

                  assume a in ( union P1);

                  then

                  consider b be set such that

                   EZ11: a in b and

                   EZ12: b in P1 by TARSKI:def 4;

                  consider p be Element of P such that

                   EZ13: b = p and

                   EZ14: p is Subset of x and

                   EZ15: p misses y by EZ12;

                  b c= (x \ y) by EZ13, EZ14, EZ15, XBOOLE_1: 86;

                  hence thesis by EZ11;

                end;

                let a be object;

                assume

                 AS0: a in (x \ y);

                then

                 U0: a in x;

                

                 U00: x in x1 & x1 is a_partition of A by A1, C1;

                

                 U1: a in A by U0, U00;

                a in ( union P) by U1, EQREL_1:def 4;

                then

                consider b be set such that

                 U2: a in b and

                 U3: b in P by TARSKI:def 4;

                consider u be set such that

                 U4: u in (x1 '/\' y1) and

                 U5: b c= u by U3, D2, SETFAM_1:def 2;

                consider xx1,yy1 be set such that

                 W3: xx1 in x1 & yy1 in y1 and

                 W4: u = (xx1 /\ yy1) by U4, SETFAM_1:def 5;

                

                 UU1: b is Subset of x

                proof

                  

                   LI1A: b c= (xx1 /\ yy1) & (xx1 /\ yy1) c= xx1 by U5, W4, XBOOLE_1: 17;

                  then

                   LI1: b c= xx1 by XBOOLE_1: 1;

                  xx1 = x

                  proof

                    assume not xx1 = x;

                    then b misses x by A1, C1, W3, LI1, EQREL_1:def 4, XBOOLE_1: 63;

                    hence thesis by AS0, U2, XBOOLE_0:def 4;

                  end;

                  hence thesis by LI1A, XBOOLE_1: 1;

                end;

                b misses y

                proof

                  assume not b misses y;

                  then

                  consider z be object such that

                   WA1: z in (b /\ y) by XBOOLE_0:def 1;

                  consider v be set such that

                   K1: v in (x1 '/\' y1) and

                   K2: b c= v by U3, D2, SETFAM_1:def 2;

                  consider xx1,yy1 be set such that

                   W3: xx1 in x1 & yy1 in y1 and

                   W4: v = (xx1 /\ yy1) by K1, SETFAM_1:def 5;

                  

                   LEM: not (xx1 /\ yy1) = (x /\ y)

                  proof

                    assume (xx1 /\ yy1) = (x /\ y);

                    then a in y by U2, W4, K2, XBOOLE_0:def 4;

                    hence thesis by AS0, XBOOLE_0:def 5;

                  end;

                  z in (b /\ y) & (b /\ y) c= ((xx1 /\ yy1) /\ y) by WA1, K2, W4, XBOOLE_1: 26;

                  then z in (xx1 /\ yy1) & z in y by XBOOLE_0:def 4;

                  then z in xx1 & z in yy1 & z in y by XBOOLE_0:def 4;

                  then

                   AS2: z in (yy1 /\ y) by XBOOLE_0:def 4;

                  

                   AS2A: yy1 = y by A3, C3, W3, EQREL_1:def 4, AS2, XBOOLE_0:def 7;

                  a in xx1 & a in x by U2, K2, W4, AS0, XBOOLE_0:def 4;

                  then a in (xx1 /\ x) by XBOOLE_0:def 4;

                  hence thesis by A1, C1, W3, EQREL_1:def 4, LEM, AS2A, XBOOLE_0:def 7;

                end;

                then b in P1 by UU1, U3;

                hence thesis by U2, TARSKI:def 4;

              end;

              for a be Subset of (x \ y) st a in P1 holds a <> {} & for b be Subset of (x \ y) st b in P1 holds a = b or a misses b

              proof

                let a be Subset of (x \ y);

                assume a in P1;

                then

                 CC: ex a0 be Element of P st a = a0 & a0 is Subset of x & a0 misses y;

                hence a <> {} ;

                for b be Subset of (x \ y) st b in P1 holds a = b or a misses b

                proof

                  let b be Subset of (x \ y);

                  assume b in P1;

                  then ex b0 be Element of P st b = b0 & b0 is Subset of x & b0 misses y;

                  hence thesis by CC, EQREL_1:def 4;

                end;

                hence thesis;

              end;

              hence thesis by Y1, Y2, EQREL_1:def 4;

            end;

            hence thesis by T1;

          end;

          hence thesis by AA, Defdiff2;

        end;

      end;

    end;

    theorem :: SRINGS_1:19

    

     Thm99: for S be cap-finite-partition-closed Subset-Family of X, A be Element of S holds ( union (( PARTITIONS A) /\ ( Fin S))) is cap-finite-partition-closed diff-finite-partition-closed Subset-Family of A & ( union (( PARTITIONS A) /\ ( Fin S))) is with_non-empty_elements

    proof

      let S be cap-finite-partition-closed Subset-Family of X, A be Element of S;

      

       A1: ( union (( PARTITIONS A) /\ ( Fin S))) = { x where x be Element of S : x in ( union (( PARTITIONS A) /\ ( Fin S))) } by ThmVAL1;

      then

       A2: ( union (( PARTITIONS A) /\ ( Fin S))) is cap-finite-partition-closed Subset-Family of A by ThmVAL0;

      ( union (( PARTITIONS A) /\ ( Fin S))) is diff-c=-finite-partition-closed Subset-Family of A by A1, ThmVAL2;

      hence thesis by A2, LemPO;

    end;

    theorem :: SRINGS_1:20

    for S be cap-finite-partition-closed Subset-Family of X, A be Element of S holds ( { {} } \/ ( union (( PARTITIONS A) /\ ( Fin S)))) is semiring_of_sets of A

    proof

      let S be cap-finite-partition-closed Subset-Family of X, A be Element of S;

      set A1 = ( union (( PARTITIONS A) /\ ( Fin S)));

      set B = (( union (( PARTITIONS A) /\ ( Fin S))) \/ { {} });

      

       A1: A1 is cap-finite-partition-closed diff-finite-partition-closed Subset-Family of A by Thm99;

      

       A2: { {} } c= B & {} in { {} } by XBOOLE_1: 7, TARSKI:def 1;

      B c= ( bool A)

      proof

        let x be object;

        assume x in B;

        then x in A1 or x in { {} } by XBOOLE_0:def 3;

        then

         A3: x in A1 or x = {} by TARSKI:def 1;

         {} c= A by XBOOLE_1: 2;

        hence thesis by A1, A3;

      end;

      then

      reconsider B as Subset-Family of A;

      

       A4: B is cap-finite-partition-closed

      proof

        let S1,S2 be Element of B such that

         F1: (S1 /\ S2) is non empty;

        reconsider A1 as Subset-Family of A by Thm99;

        (S1 in A1 or S1 in { {} }) & (S2 in A1 or S2 in { {} }) by XBOOLE_0:def 3;

        then (S1 in A1 or S1 = {} ) & (S2 in A1 or S2 = {} ) by TARSKI:def 1;

        then S1 is Element of A1 & S2 is Element of A1 & (S1 /\ S2) is non empty & A1 is cap-finite-partition-closed by F1, Thm99;

        then

        consider P be finite Subset of A1 such that

         SOL: P is a_partition of (S1 /\ S2);

        reconsider P as finite Subset of B by XBOOLE_1: 10;

        P is finite Subset of B & P is a_partition of (S1 /\ S2) by SOL;

        hence thesis;

      end;

      B is diff-finite-partition-closed

      proof

        let S1,S2 be Element of B such that

         F1: (S1 \ S2) is non empty;

        reconsider A1 as Subset-Family of A by Thm99;

        

         F2aa: (S1 in A1 or S1 in { {} }) & (S2 in A1 or S2 in { {} }) by XBOOLE_0:def 3;

        

         V1: S2 = {} implies ex P be finite Subset of B st P is a_partition of (S1 \ S2)

        proof

          assume

           D0: S2 = {} ;

          

           D3: {S1} c= B

          proof

            let x be object;

            assume x in {S1};

            then x = S1 by TARSKI:def 1;

            hence thesis;

          end;

           {S1} is a_partition of S1 by F1, EQREL_1: 39;

          hence thesis by D0, D3;

        end;

        S2 in A1 implies ex P be finite Subset of B st P is a_partition of (S1 \ S2)

        proof

          assume S2 in A1;

          then S1 is Element of A1 & S2 is Element of A1 & (S1 \ S2) is non empty & A1 is diff-finite-partition-closed by Thm99, F1, F2aa, TARSKI:def 1;

          then

          consider P be finite Subset of A1 such that

           SOL: P is a_partition of (S1 \ S2);

          reconsider P as finite Subset of B by XBOOLE_1: 10;

          P is finite Subset of B & P is a_partition of (S1 \ S2) by SOL;

          hence thesis;

        end;

        hence thesis by V1, F2aa, TARSKI:def 1;

      end;

      hence thesis by A2, A4;

    end;

    theorem :: SRINGS_1:21

    

     thmCup: for S be cap-finite-partition-closed diff-finite-partition-closed Subset-Family of X holds { ( union x) where x be finite Subset of S : x is mutually-disjoint } is cup-closed

    proof

      let S be cap-finite-partition-closed diff-finite-partition-closed Subset-Family of X;

      set Y = { ( union x) where x be finite Subset of S : x is mutually-disjoint };

      let a,b be set;

      assume

       A: a in Y & b in Y;

      then

      consider a0 be finite Subset of S such that

       B: a = ( union a0) & a0 is mutually-disjoint;

      consider b0 be finite Subset of S such that

       C: b = ( union b0) & b0 is mutually-disjoint by A;

      consider SM be FinSequence such that

       F1: ( rng SM) = (a0 \/ b0) by FINSEQ_1: 52;

      consider P be finite Subset of S such that

       VU: P is a_partition of ( Union SM) and for Y be Element of ( rng SM) holds Y = ( union { s where s be Element of S : s in P & s c= Y }) by F1, Thm87;

      ( Union SM) = (( union a0) \/ ( union b0)) by F1, ZFMISC_1: 78;

      then

       VB: ( union P) = (a \/ b) by B, C, VU, EQREL_1:def 4;

      for x,y be set st x in P & y in P & x <> y holds x misses y by VU, EQREL_1:def 4;

      then P is mutually-disjoint by TAXONOM2:def 5;

      hence thesis by VB;

    end;

    theorem :: SRINGS_1:22

    for S be cap-finite-partition-closed diff-finite-partition-closed Subset-Family of X holds { ( union x) where x be finite Subset of S : x is mutually-disjoint } is Ring_of_sets

    proof

      let S be cap-finite-partition-closed diff-finite-partition-closed Subset-Family of X;

      { ( union x) where x be finite Subset of S : x is mutually-disjoint } is cap-closed cup-closed by Thm86, thmCup;

      hence thesis by thmIL;

    end;