incproj.miz



    begin

    reserve CPS for proper CollSp,

B for Subset of CPS,

p for Point of CPS,

x,y,z,Y for set;

    definition

      let CPS;

      :: original: LINE

      redefine

      mode LINE of CPS -> Subset of CPS ;

      coherence

      proof

        let x be LINE of CPS;

        x c= the carrier of CPS

        proof

          consider a,b be Point of CPS such that a <> b and

           A1: x = ( Line (a,b)) by COLLSP:def 7;

          let z be object;

          assume z in x;

          then z in { p : (a,b,p) are_collinear } by A1, COLLSP:def 5;

          then ex p be Point of CPS st z = p & (a,b,p) are_collinear ;

          hence z in the carrier of CPS;

        end;

        hence thesis;

      end;

    end

    definition

      let CPS;

      :: INCPROJ:def1

      func ProjectiveLines (CPS) -> set equals { B : B is LINE of CPS };

      coherence ;

    end

    registration

      let CPS;

      cluster ( ProjectiveLines CPS) -> non empty;

      coherence

      proof

        set x = the LINE of CPS;

        x in ( ProjectiveLines CPS);

        hence thesis;

      end;

    end

    theorem :: INCPROJ:1

    

     Th1: x is LINE of CPS iff x is Element of ( ProjectiveLines CPS)

    proof

      hereby

        assume x is LINE of CPS;

        then x in { B : B is LINE of CPS };

        hence x is Element of ( ProjectiveLines CPS);

      end;

      assume x is Element of ( ProjectiveLines CPS);

      then x in ( ProjectiveLines CPS);

      then ex B st x = B & B is LINE of CPS;

      hence thesis;

    end;

    definition

      let CPS;

      :: INCPROJ:def2

      func Proj_Inc (CPS) -> Relation of the carrier of CPS, ( ProjectiveLines CPS) means

      : Def2: for x,y be object holds [x, y] in it iff x in the carrier of CPS & y in ( ProjectiveLines CPS) & ex Y st y = Y & x in Y;

      existence

      proof

        defpred P[ object, object] means ex Y st $2 = Y & $1 in Y;

        ex IT be Relation of the carrier of CPS, ( ProjectiveLines CPS) st for x,y be object holds [x, y] in IT iff x in the carrier of CPS & y in ( ProjectiveLines CPS) & P[x, y] from RELSET_1:sch 1;

        hence thesis;

      end;

      uniqueness

      proof

        let R1,R2 be Relation of the carrier of CPS, ( ProjectiveLines CPS) such that

         A1: for x,y be object holds [x, y] in R1 iff x in the carrier of CPS & y in ( ProjectiveLines CPS) & ex Y st y = Y & x in Y and

         A2: for x,y be object holds [x, y] in R2 iff x in the carrier of CPS & y in ( ProjectiveLines CPS) & ex Y st y = Y & x in Y;

        now

          let x,y be object;

           A3:

          now

            assume

             A4: [x, y] in R2;

            then

             A5: ex Y st y = Y & x in Y by A2;

            x in the carrier of CPS & y in ( ProjectiveLines CPS) by A2, A4;

            hence [x, y] in R1 by A1, A5;

          end;

          now

            assume

             A6: [x, y] in R1;

            then

             A7: ex Y st y = Y & x in Y by A1;

            x in the carrier of CPS & y in ( ProjectiveLines CPS) by A1, A6;

            hence [x, y] in R2 by A2, A7;

          end;

          hence [x, y] in R1 iff [x, y] in R2 by A3;

        end;

        hence R1 = R2 by RELAT_1:def 2;

      end;

    end

    definition

      let CPS;

      :: INCPROJ:def3

      func IncProjSp_of (CPS) -> IncProjStr equals IncProjStr (# the carrier of CPS, ( ProjectiveLines CPS), ( Proj_Inc CPS) #);

      coherence ;

    end

    registration

      let CPS;

      cluster ( IncProjSp_of CPS) -> strict;

      coherence ;

    end

    theorem :: INCPROJ:2

    the Points of ( IncProjSp_of CPS) = the carrier of CPS & the Lines of ( IncProjSp_of CPS) = ( ProjectiveLines CPS) & the Inc of ( IncProjSp_of CPS) = ( Proj_Inc CPS);

    theorem :: INCPROJ:3

    x is Point of CPS iff x is POINT of ( IncProjSp_of CPS);

    theorem :: INCPROJ:4

    x is LINE of CPS iff x is LINE of ( IncProjSp_of CPS) by Th1;

    reserve a,b,c,p,q for POINT of ( IncProjSp_of CPS),

P,Q for LINE of ( IncProjSp_of CPS),

a9,b9,c9,p9,q9,r9 for Point of CPS,

P9 for LINE of CPS;

    theorem :: INCPROJ:5

    

     Th5: p = p9 & P = P9 implies (p on P iff p9 in P9)

    proof

      reconsider P99 = P9 as LINE of ( IncProjSp_of CPS) by Th1;

      reconsider P999 = P99 as Element of ( ProjectiveLines CPS);

      assume

       A1: p = p9 & P = P9;

      hereby

        assume p on P;

        then [p9, P9] in ( Proj_Inc CPS) by A1;

        then ex Y st P9 = Y & p9 in Y by Def2;

        hence p9 in P9;

      end;

      assume p9 in P9;

      then [p9, P999] in ( Proj_Inc CPS) by Def2;

      hence thesis by A1;

    end;

    theorem :: INCPROJ:6

    

     Th6: ex a9, b9, c9 st a9 <> b9 & b9 <> c9 & c9 <> a9

    proof

      consider a99,b99,c99 be Point of CPS such that

       A1: not (a99,b99,c99) are_collinear by COLLSP:def 6;

      

       A2: c99 <> a99 by A1, COLLSP: 2;

      a99 <> b99 & b99 <> c99 by A1, COLLSP: 2;

      hence thesis by A2;

    end;

    theorem :: INCPROJ:7

    

     Th7: ex b9 st a9 <> b9

    proof

      consider p9, q9, r9 such that

       A1: p9 <> q9 and q9 <> r9 and r9 <> p9 by Th6;

      a9 <> p9 or a9 <> q9 by A1;

      hence thesis;

    end;

    theorem :: INCPROJ:8

    

     Th8: p on P & q on P & p on Q & q on Q implies p = q or P = Q

    proof

      reconsider p9 = p, q9 = q as Point of CPS;

      reconsider P9 = P, Q9 = Q as LINE of CPS by Th1;

      assume that

       A1: p on P & q on P and

       A2: p on Q & q on Q and

       A3: p <> q;

      

       A4: p9 in Q9 & q9 in Q9 by A2, Th5;

      p9 in P9 & q9 in P9 by A1, Th5;

      hence thesis by A3, A4, COLLSP: 20;

    end;

    theorem :: INCPROJ:9

    

     Th9: ex P st p on P & q on P

    proof

      reconsider p9 = p, q9 = q as Point of CPS;

       A1:

      now

        consider r9 such that

         A2: p9 <> r9 by Th7;

        consider P9 be LINE of CPS such that

         A3: p9 in P9 and r9 in P9 by A2, COLLSP: 15;

        reconsider P = P9 as LINE of ( IncProjSp_of CPS) by Th1;

        assume

         A4: p9 = q9;

        p on P by A3, Th5;

        hence thesis by A4;

      end;

      now

        assume p9 <> q9;

        then

        consider P9 be LINE of CPS such that

         A5: p9 in P9 & q9 in P9 by COLLSP: 15;

        reconsider P = P9 as LINE of ( IncProjSp_of CPS) by Th1;

        p on P & q on P by A5, Th5;

        hence thesis;

      end;

      hence thesis by A1;

    end;

    theorem :: INCPROJ:10

    

     Th10: a = a9 & b = b9 & c = c9 implies ((a9,b9,c9) are_collinear iff ex P st a on P & b on P & c on P)

    proof

      assume that

       A1: a = a9 and

       A2: b = b9 and

       A3: c = c9;

      hereby

        assume

         A4: (a9,b9,c9) are_collinear ;

         A5:

        now

          set X = ( Line (a9,b9));

          assume a9 <> b9;

          then

          reconsider P9 = X as LINE of CPS by COLLSP:def 7;

          reconsider P = P9 as LINE of ( IncProjSp_of CPS) by Th1;

          a9 in X by COLLSP: 10;

          then

           A6: a on P by A1, Th5;

          b9 in X by COLLSP: 10;

          then

           A7: b on P by A2, Th5;

          c9 in X by A4, COLLSP: 11;

          then c on P by A3, Th5;

          hence ex P st a on P & b on P & c on P by A6, A7;

        end;

        now

          assume

           A8: a9 = b9;

          ex P st b on P & c on P by Th9;

          hence ex P st a on P & b on P & c on P by A1, A2, A8;

        end;

        hence ex P st a on P & b on P & c on P by A5;

      end;

      given P such that

       A9: a on P & b on P and

       A10: c on P;

      reconsider P9 = P as LINE of CPS by Th1;

      

       A11: c9 in P9 by A3, A10, Th5;

      a9 in P9 & b9 in P9 by A1, A2, A9, Th5;

      hence thesis by A11, COLLSP: 16;

    end;

    theorem :: INCPROJ:11

    

     Th11: ex p, P st not p on P

    proof

      consider p9, q9, r9 such that

       A1: not (p9,q9,r9) are_collinear by COLLSP:def 6;

      set X = ( Line (p9,q9));

      p9 <> q9 by A1, COLLSP: 2;

      then

      reconsider P9 = X as LINE of CPS by COLLSP:def 7;

      reconsider P = P9 as LINE of ( IncProjSp_of CPS) by Th1;

      reconsider r = r9 as POINT of ( IncProjSp_of CPS);

       not r on P

      proof

        assume not thesis;

        then r9 in X by Th5;

        hence contradiction by A1, COLLSP: 11;

      end;

      hence thesis;

    end;

    reserve CPS for CollProjectiveSpace,

a,b,c,d,p,q for POINT of ( IncProjSp_of CPS),

P,Q,S,M,N for LINE of ( IncProjSp_of CPS),

a9,b9,c9,d9,p9,q9 for Point of CPS;

    theorem :: INCPROJ:12

    

     Th12: ex a, b, c st a <> b & b <> c & c <> a & a on P & b on P & c on P

    proof

      reconsider P9 = P as LINE of CPS by Th1;

      consider a99,b99 be Point of CPS such that

       A1: a99 <> b99 and

       A2: P9 = ( Line (a99,b99)) by COLLSP:def 7;

      consider c9 such that

       A3: a99 <> c9 & b99 <> c9 and

       A4: (a99,b99,c9) are_collinear by ANPROJ_2:def 10;

      reconsider a = a99, b = b99, c = c9 as POINT of ( IncProjSp_of CPS);

      take a, b, c;

      thus a <> b & b <> c & c <> a by A1, A3;

      a99 in P9 by A2, COLLSP: 10;

      then

       A5: a on P by Th5;

      b99 in P9 by A2, COLLSP: 10;

      then

       A6: b on P by Th5;

      ex Q st a on Q & b on Q & c on Q by A4, Th10;

      hence thesis by A1, A5, A6, Th8;

    end;

    theorem :: INCPROJ:13

    

     Th13: a on M & b on M & c on N & d on N & p on M & p on N & a on P & c on P & b on Q & d on Q & not p on P & not p on Q & M <> N implies ex q st q on P & q on Q

    proof

      assume that

       A1: a on M and

       A2: b on M and

       A3: c on N and

       A4: d on N and

       A5: p on M & p on N and

       A6: a on P and

       A7: c on P and

       A8: b on Q and

       A9: d on Q and

       A10: not p on P and

       A11: not p on Q and

       A12: M <> N;

      reconsider a9 = a, b9 = b, c9 = c, d9 = d, p9 = p as Point of CPS;

      (b9,p9,a9) are_collinear & (p9,d9,c9) are_collinear by A1, A2, A3, A4, A5, Th10;

      then

      consider q9 such that

       A13: (b9,d9,q9) are_collinear and

       A14: (a9,c9,q9) are_collinear by ANPROJ_2:def 9;

      reconsider q = q9 as POINT of ( IncProjSp_of CPS);

      

       A15: ex P2 be LINE of ( IncProjSp_of CPS) st b on P2 & d on P2 & q on P2 by A13, Th10;

      b <> d by A2, A4, A5, A8, A11, A12, Th8;

      then

       A16: q on Q by A8, A9, A15, Th8;

      

       A17: ex P1 be LINE of ( IncProjSp_of CPS) st a on P1 & c on P1 & q on P1 by A14, Th10;

      a <> c by A1, A3, A5, A6, A10, A12, Th8;

      then q on P by A6, A7, A17, Th8;

      hence thesis by A16;

    end;

    theorem :: INCPROJ:14

    

     Th14: (for a9, b9, c9, d9 holds ex p9 st (a9,b9,p9) are_collinear & (c9,d9,p9) are_collinear ) implies for M, N holds ex q st q on M & q on N

    proof

      assume

       A1: for a9, b9, c9, d9 holds ex p9 st (a9,b9,p9) are_collinear & (c9,d9,p9) are_collinear ;

      let M, N;

      reconsider M9 = M, N9 = N as LINE of CPS by Th1;

      consider a9, b9 such that a9 <> b9 and

       A2: M9 = ( Line (a9,b9)) by COLLSP:def 7;

      consider c9, d9 such that c9 <> d9 and

       A3: N9 = ( Line (c9,d9)) by COLLSP:def 7;

      consider p9 such that

       A4: (a9,b9,p9) are_collinear and

       A5: (c9,d9,p9) are_collinear by A1;

      reconsider q = p9 as POINT of ( IncProjSp_of CPS);

      p9 in N9 by A3, A5, COLLSP: 11;

      then

       A6: q on N by Th5;

      p9 in M9 by A2, A4, COLLSP: 11;

      then q on M by Th5;

      hence thesis by A6;

    end;

    theorem :: INCPROJ:15

    

     Th15: (ex p,p1,r,r1 be Point of CPS st not ex s be Point of CPS st ((p,p1,s) are_collinear & (r,r1,s) are_collinear )) implies ex M, N st not ex q st q on M & q on N

    proof

      given p,p1,r,r1 be Point of CPS such that

       A1: not ex s be Point of CPS st ((p,p1,s) are_collinear & (r,r1,s) are_collinear );

      set M99 = ( Line (p,p1)), N99 = ( Line (r,r1));

      p <> p1 & r <> r1

      proof

         A2:

        now

          assume p = p1;

          then

           A3: (p,p1,r1) are_collinear by COLLSP: 2;

          (r,r1,r1) are_collinear by COLLSP: 2;

          hence contradiction by A1, A3;

        end;

         A4:

        now

          assume r = r1;

          then (p,p1,p1) are_collinear & (r,r1,p1) are_collinear by COLLSP: 2;

          hence contradiction by A1;

        end;

        assume not thesis;

        hence contradiction by A2, A4;

      end;

      then

      reconsider M9 = M99, N9 = N99 as LINE of CPS by COLLSP:def 7;

      reconsider M = M9, N = N9 as LINE of ( IncProjSp_of CPS) by Th1;

      take M, N;

      thus not ex q st q on M & q on N

      proof

        assume not thesis;

        then

        consider q such that

         A5: q on M and

         A6: q on N;

        reconsider q9 = q as Point of CPS;

        q9 in N99 by A6, Th5;

        then

         A7: (r,r1,q9) are_collinear by COLLSP: 11;

        q9 in M99 by A5, Th5;

        then (p,p1,q9) are_collinear by COLLSP: 11;

        hence contradiction by A1, A7;

      end;

    end;

    theorem :: INCPROJ:16

    

     Th16: (for p,p1,q,q1,r2 be Point of CPS holds ex r,r1 be Point of CPS st (p,q,r) are_collinear & (p1,q1,r1) are_collinear & (r2,r,r1) are_collinear ) implies for a, M, N holds ex b, c, S st a on S & b on S & c on S & b on M & c on N

    proof

      assume

       A1: for p,p1,q,q1,r2 be Point of CPS holds ex r,r1 be Point of CPS st (p,q,r) are_collinear & (p1,q1,r1) are_collinear & (r2,r,r1) are_collinear ;

      let a, M, N;

      reconsider M9 = M, N9 = N as LINE of CPS by Th1;

      reconsider a9 = a as Point of CPS;

      consider p,q be Point of CPS such that p <> q and

       A2: M9 = ( Line (p,q)) by COLLSP:def 7;

      consider p1,q1 be Point of CPS such that p1 <> q1 and

       A3: N9 = ( Line (p1,q1)) by COLLSP:def 7;

      consider b9, c9 such that

       A4: (p,q,b9) are_collinear and

       A5: (p1,q1,c9) are_collinear and

       A6: (a9,b9,c9) are_collinear by A1;

      reconsider b = b9, c = c9 as POINT of ( IncProjSp_of CPS);

      b9 in M9 by A2, A4, COLLSP: 11;

      then

       A7: b on M by Th5;

      c9 in N9 by A3, A5, COLLSP: 11;

      then

       A8: c on N by Th5;

      ex S st a on S & b on S & c on S by A6, Th10;

      hence thesis by A7, A8;

    end;

    theorem :: INCPROJ:17

    

     Th17: (for p1,r2,q,r1,q1,p,r be Point of CPS holds ((p1,r2,q) are_collinear & (r1,q1,q) are_collinear & (p1,r1,p) are_collinear & (r2,q1,p) are_collinear & (p1,q1,r) are_collinear & (r2,r1,r) are_collinear & (p,q,r) are_collinear implies ((p1,r2,q1) are_collinear or (p1,r2,r1) are_collinear or (p1,r1,q1) are_collinear or (r2,r1,q1) are_collinear ))) implies for p,q,r,s,a,b,c be POINT of ( IncProjSp_of CPS) holds for L,Q,R,S,A,B,C be LINE of ( IncProjSp_of CPS) st not q on L & not r on L & not p on Q & not s on Q & not p on R & not r on R & {a, p, s} on L & {a, q, r} on Q & {b, q, s} on R & {b, p, r} on S & {c, p, q} on A & {c, r, s} on B & {a, b} on C holds not c on C

    proof

      assume

       A1: for p1,r2,q,r1,q1,p,r be Element of CPS holds ((p1,r2,q) are_collinear & (r1,q1,q) are_collinear & (p1,r1,p) are_collinear & (r2,q1,p) are_collinear & (p1,q1,r) are_collinear & (r2,r1,r) are_collinear & (p,q,r) are_collinear implies ((p1,r2,q1) are_collinear or (p1,r2,r1) are_collinear or (p1,r1,q1) are_collinear or (r2,r1,q1) are_collinear ));

      let p,q,r,s,a,b,c be POINT of ( IncProjSp_of CPS);

      let L,Q,R,S,A,B,C be LINE of ( IncProjSp_of CPS) such that

       A2: not q on L and

       A3: not r on L and

       A4: not p on Q and

       A5: not s on Q and

       A6: not p on R and

       A7: not r on R and

       A8: {a, p, s} on L and

       A9: {a, q, r} on Q and

       A10: {b, q, s} on R and

       A11: {b, p, r} on S and

       A12: {c, p, q} on A and

       A13: {c, r, s} on B and

       A14: {a, b} on C;

      reconsider p9 = p, q9 = q, r9 = r, s9 = s, a9 = a, b9 = b, c9 = c as Point of CPS;

      

       A15: p on L & s on L by A8, INCSP_1: 2;

      

       A16: s on R by A10, INCSP_1: 2;

       A17:

      now

        assume (p9,r9,s9) are_collinear ;

        then

         A18: ex K be LINE of ( IncProjSp_of CPS) st p on K & r on K & s on K by Th10;

        hence s on S by A3, A6, A15, A16, Th8;

        thus contradiction by A3, A6, A15, A16, A18, Th8;

      end;

       A19:

      now

        assume (p9,s9,q9) are_collinear ;

        then

         A20: ex K be LINE of ( IncProjSp_of CPS) st p on K & s on K & q on K by Th10;

        hence p on R by A2, A15, A16, Th8;

        thus contradiction by A2, A6, A15, A16, A20, Th8;

      end;

      a on L by A8, INCSP_1: 2;

      then

       A21: (p9,s9,a9) are_collinear by A15, Th10;

      assume

       A22: not thesis;

      a on C & b on C by A14, INCSP_1: 1;

      then

       A23: (a9,b9,c9) are_collinear by A22, Th10;

      

       A24: q on Q & r on Q by A9, INCSP_1: 2;

      

       A25: q on R by A10, INCSP_1: 2;

       A26:

      now

        assume (p9,r9,q9) are_collinear ;

        then

         A27: ex K be LINE of ( IncProjSp_of CPS) st p on K & r on K & q on K by Th10;

        hence q on S by A4, A7, A24, A25, Th8;

        thus contradiction by A4, A7, A24, A25, A27, Th8;

      end;

       A28:

      now

        assume (r9,s9,q9) are_collinear ;

        then

         A29: ex K be LINE of ( IncProjSp_of CPS) st r on K & s on K & q on K by Th10;

        hence r on R by A5, A24, A25, Th8;

        thus contradiction by A5, A7, A24, A25, A29, Th8;

      end;

      a on Q by A9, INCSP_1: 2;

      then

       A30: (r9,q9,a9) are_collinear by A24, Th10;

      

       A31: r on S by A11, INCSP_1: 2;

      b on S & p on S by A11, INCSP_1: 2;

      then

       A32: (p9,r9,b9) are_collinear by A31, Th10;

      

       A33: s on B by A13, INCSP_1: 2;

      c on B & r on B by A13, INCSP_1: 2;

      then

       A34: (r9,s9,c9) are_collinear by A33, Th10;

      

       A35: q on A by A12, INCSP_1: 2;

      c on A & p on A by A12, INCSP_1: 2;

      then

       A36: (p9,q9,c9) are_collinear by A35, Th10;

      b on R by A10, INCSP_1: 2;

      then (s9,q9,b9) are_collinear by A25, A16, Th10;

      hence contradiction by A1, A23, A32, A21, A30, A36, A34, A26, A17, A19, A28;

    end;

    theorem :: INCPROJ:18

    

     Th18: (for o,p1,p2,p3,q1,q2,q3,r1,r2,r3 be Point of CPS st o <> q1 & p1 <> q1 & o <> q2 & p2 <> q2 & o <> q3 & p3 <> q3 & not (o,p1,p2) are_collinear & not (o,p1,p3) are_collinear & not (o,p2,p3) are_collinear & (p1,p2,r3) are_collinear & (q1,q2,r3) are_collinear & (p2,p3,r1) are_collinear & (q2,q3,r1) are_collinear & (p1,p3,r2) are_collinear & (q1,q3,r2) are_collinear & (o,p1,q1) are_collinear & (o,p2,q2) are_collinear & (o,p3,q3) are_collinear holds (r1,r2,r3) are_collinear ) implies for o,b1,a1,b2,a2,b3,a3,r,s,t be POINT of ( IncProjSp_of CPS) holds for C1,C2,C3,A1,A2,A3,B1,B2,B3 be LINE of ( IncProjSp_of CPS) st {o, b1, a1} on C1 & {o, a2, b2} on C2 & {o, a3, b3} on C3 & {a3, a2, t} on A1 & {a3, r, a1} on A2 & {a2, s, a1} on A3 & {t, b2, b3} on B1 & {b1, r, b3} on B2 & {b1, s, b2} on B3 & (C1,C2,C3) are_mutually_distinct & o <> a1 & o <> a2 & o <> a3 & o <> b1 & o <> b2 & o <> b3 & a1 <> b1 & a2 <> b2 & a3 <> b3 holds ex O be LINE of ( IncProjSp_of CPS) st {r, s, t} on O

    proof

      assume

       A1: for o,p1,p2,p3,q1,q2,q3,r1,r2,r3 be Element of CPS st o <> q1 & p1 <> q1 & o <> q2 & p2 <> q2 & o <> q3 & p3 <> q3 & not (o,p1,p2) are_collinear & not (o,p1,p3) are_collinear & not (o,p2,p3) are_collinear & (p1,p2,r3) are_collinear & (q1,q2,r3) are_collinear & (p2,p3,r1) are_collinear & (q2,q3,r1) are_collinear & (p1,p3,r2) are_collinear & (q1,q3,r2) are_collinear & (o,p1,q1) are_collinear & (o,p2,q2) are_collinear & (o,p3,q3) are_collinear holds (r1,r2,r3) are_collinear ;

      let o,b1,a1,b2,a2,b3,a3,r,s,t be POINT of ( IncProjSp_of CPS);

      let C1,C2,C3,A1,A2,A3,B1,B2,B3 be LINE of ( IncProjSp_of CPS) such that

       A2: {o, b1, a1} on C1 and

       A3: {o, a2, b2} on C2 and

       A4: {o, a3, b3} on C3 and

       A5: {a3, a2, t} on A1 and

       A6: {a3, r, a1} on A2 and

       A7: {a2, s, a1} on A3 and

       A8: {t, b2, b3} on B1 and

       A9: {b1, r, b3} on B2 and

       A10: {b1, s, b2} on B3 and

       A11: (C1,C2,C3) are_mutually_distinct and

       A12: o <> a1 & o <> a2 & o <> a3 and

       A13: o <> b1 and

       A14: o <> b2 and

       A15: o <> b3 and

       A16: a1 <> b1 & a2 <> b2 & a3 <> b3;

      reconsider o9 = o, b19 = b1, a19 = a1, b29 = b2, a29 = a2, b39 = b3, a39 = a3, r9 = r, s9 = s, t9 = t as Element of CPS;

      

       A17: o on C2 & b2 on C2 by A3, INCSP_1: 2;

      

       A18: s on B3 by A10, INCSP_1: 2;

      b2 on B3 & b1 on B3 by A10, INCSP_1: 2;

      then

       A19: (b19,b29,s9) are_collinear by A18, Th10;

      

       A20: r on B2 by A9, INCSP_1: 2;

      b3 on B2 & b1 on B2 by A9, INCSP_1: 2;

      then

       A21: (b19,b39,r9) are_collinear by A20, Th10;

      

       A22: t on B1 by A8, INCSP_1: 2;

      b3 on B1 & b2 on B1 by A8, INCSP_1: 2;

      then

       A23: (b29,b39,t9) are_collinear by A22, Th10;

      

       A24: s on A3 by A7, INCSP_1: 2;

      a2 on A3 & a1 on A3 by A7, INCSP_1: 2;

      then

       A25: (a19,a29,s9) are_collinear by A24, Th10;

      

       A26: o on C3 & b3 on C3 by A4, INCSP_1: 2;

      a3 on C3 by A4, INCSP_1: 2;

      then

       A27: (o9,b39,a39) are_collinear by A26, Th10;

      a2 on C2 by A3, INCSP_1: 2;

      then

       A28: (o9,b29,a29) are_collinear by A17, Th10;

      

       A29: r on A2 by A6, INCSP_1: 2;

      a3 on A2 & a1 on A2 by A6, INCSP_1: 2;

      then

       A30: (a19,a39,r9) are_collinear by A29, Th10;

      

       A31: t on A1 by A5, INCSP_1: 2;

      a3 on A1 & a2 on A1 by A5, INCSP_1: 2;

      then

       A32: (a29,a39,t9) are_collinear by A31, Th10;

      

       A33: o on C1 & b1 on C1 by A2, INCSP_1: 2;

      

       A34: not (o9,b19,b29) are_collinear & not (o9,b19,b39) are_collinear & not (o9,b29,b39) are_collinear

      proof

         A35:

        now

          assume (o9,b19,b39) are_collinear ;

          then

          consider K be LINE of ( IncProjSp_of CPS) such that

           A36: o on K & b1 on K & b3 on K by Th10;

          K = C1 & K = C3 by A13, A15, A33, A26, A36, Th8;

          hence contradiction by A11, ZFMISC_1:def 5;

        end;

         A37:

        now

          assume (o9,b19,b29) are_collinear ;

          then

          consider K be LINE of ( IncProjSp_of CPS) such that

           A38: o on K & b1 on K & b2 on K by Th10;

          K = C1 & K = C2 by A13, A14, A33, A17, A38, Th8;

          hence contradiction by A11, ZFMISC_1:def 5;

        end;

         A39:

        now

          assume (o9,b29,b39) are_collinear ;

          then

          consider K be LINE of ( IncProjSp_of CPS) such that

           A40: o on K & b2 on K & b3 on K by Th10;

          K = C2 & K = C3 by A14, A15, A17, A26, A40, Th8;

          hence contradiction by A11, ZFMISC_1:def 5;

        end;

        assume not thesis;

        hence contradiction by A37, A35, A39;

      end;

      a1 on C1 by A2, INCSP_1: 2;

      then (o9,b19,a19) are_collinear by A33, Th10;

      then (t9,r9,s9) are_collinear by A1, A12, A16, A19, A25, A21, A30, A23, A32, A28, A27, A34;

      then

      consider O be LINE of ( IncProjSp_of CPS) such that

       A41: t on O & r on O & s on O by Th10;

       {r, s, t} on O by A41, INCSP_1: 2;

      hence thesis;

    end;

    theorem :: INCPROJ:19

    

     Th19: (for o,p1,p2,p3,q1,q2,q3,r1,r2,r3 be Point of CPS st o <> p2 & o <> p3 & p2 <> p3 & p1 <> p2 & p1 <> p3 & o <> q2 & o <> q3 & q2 <> q3 & q1 <> q2 & q1 <> q3 & not (o,p1,q1) are_collinear & (o,p1,p2) are_collinear & (o,p1,p3) are_collinear & (o,q1,q2) are_collinear & (o,q1,q3) are_collinear & (p1,q2,r3) are_collinear & (q1,p2,r3) are_collinear & (p1,q3,r2) are_collinear & (p3,q1,r2) are_collinear & (p2,q3,r1) are_collinear & (p3,q2,r1) are_collinear holds (r1,r2,r3) are_collinear ) implies for o,a1,a2,a3,b1,b2,b3,c1,c2,c3 be POINT of ( IncProjSp_of CPS) holds for A1,A2,A3,B1,B2,B3,C1,C2,C3 be LINE of ( IncProjSp_of CPS) st (o,a1,a2,a3) are_mutually_distinct & (o,b1,b2,b3) are_mutually_distinct & A3 <> B3 & o on A3 & o on B3 & {a2, b3, c1} on A1 & {a3, b1, c2} on B1 & {a1, b2, c3} on C1 & {a1, b3, c2} on A2 & {a3, b2, c1} on B2 & {a2, b1, c3} on C2 & {b1, b2, b3} on A3 & {a1, a2, a3} on B3 & {c1, c2} on C3 holds c3 on C3

    proof

      assume

       A1: for o,p1,p2,p3,q1,q2,q3,r1,r2,r3 be Point of CPS st o <> p2 & o <> p3 & p2 <> p3 & p1 <> p2 & p1 <> p3 & o <> q2 & o <> q3 & q2 <> q3 & q1 <> q2 & q1 <> q3 & not (o,p1,q1) are_collinear & (o,p1,p2) are_collinear & (o,p1,p3) are_collinear & (o,q1,q2) are_collinear & (o,q1,q3) are_collinear & (p1,q2,r3) are_collinear & (q1,p2,r3) are_collinear & (p1,q3,r2) are_collinear & (p3,q1,r2) are_collinear & (p2,q3,r1) are_collinear & (p3,q2,r1) are_collinear holds (r1,r2,r3) are_collinear ;

      let o,a1,a2,a3,b1,b2,b3,c1,c2,c3 be POINT of ( IncProjSp_of CPS);

      let A1,A2,A3,B1,B2,B3,C1,C2,C3 be LINE of ( IncProjSp_of CPS) such that

       A2: (o,a1,a2,a3) are_mutually_distinct and

       A3: (o,b1,b2,b3) are_mutually_distinct and

       A4: A3 <> B3 and

       A5: o on A3 and

       A6: o on B3 and

       A7: {a2, b3, c1} on A1 and

       A8: {a3, b1, c2} on B1 and

       A9: {a1, b2, c3} on C1 and

       A10: {a1, b3, c2} on A2 and

       A11: {a3, b2, c1} on B2 and

       A12: {a2, b1, c3} on C2 and

       A13: {b1, b2, b3} on A3 and

       A14: {a1, a2, a3} on B3 and

       A15: {c1, c2} on C3;

      reconsider o9 = o, a19 = a1, a29 = a2, a39 = a3, b19 = b1, b29 = b2, b39 = b3, c19 = c1, c29 = c2, c39 = c3 as Point of CPS;

      

       A16: b1 on A3 by A13, INCSP_1: 2;

      

       A17: c3 on C1 by A9, INCSP_1: 2;

      a1 on C1 & b2 on C1 by A9, INCSP_1: 2;

      then

       A18: (a19,b29,c39) are_collinear by A17, Th10;

      

       A19: c1 on A1 by A7, INCSP_1: 2;

      

       A20: o9 <> b39 & b29 <> b39 by A3, ZFMISC_1:def 6;

      

       A21: a29 <> a39 & a19 <> a29 by A2, ZFMISC_1:def 6;

      

       A22: b3 on A2 & c2 on A2 by A10, INCSP_1: 2;

      

       A23: a1 on A2 by A10, INCSP_1: 2;

      then

       A24: (a19,b39,c29) are_collinear by A22, Th10;

      

       A25: b19 <> b29 & b19 <> b39 by A3, ZFMISC_1:def 6;

      

       A26: b3 on A1 by A7, INCSP_1: 2;

      

       A27: a1 on B3 by A14, INCSP_1: 2;

      

       A28: not (o9,a19,b19) are_collinear

      proof

        

         A29: o <> a1 by A2, ZFMISC_1:def 6;

        assume not thesis;

        then

        consider K be LINE of ( IncProjSp_of CPS) such that

         A30: o on K and

         A31: a1 on K and

         A32: b1 on K by Th10;

        o <> b1 by A3, ZFMISC_1:def 6;

        then K = A3 by A5, A16, A30, A32, Th8;

        hence contradiction by A4, A6, A27, A30, A31, A29, Th8;

      end;

      

       A33: c3 on C2 by A12, INCSP_1: 2;

      a2 on C2 & b1 on C2 by A12, INCSP_1: 2;

      then

       A34: (b19,a29,c39) are_collinear by A33, Th10;

      

       A35: a3 on B1 by A8, INCSP_1: 2;

      

       A36: b2 on A3 by A13, INCSP_1: 2;

      then

       A37: (o9,b19,b29) are_collinear by A5, A16, Th10;

      

       A38: a3 on B2 & c1 on B2 by A11, INCSP_1: 2;

      

       A39: b2 on B2 by A11, INCSP_1: 2;

      then

       A40: (a39,b29,c19) are_collinear by A38, Th10;

      

       A41: b3 on A3 by A13, INCSP_1: 2;

      then

       A42: (o9,b19,b39) are_collinear by A5, A16, Th10;

      

       A43: a19 <> a39 & o9 <> b29 by A2, A3, ZFMISC_1:def 6;

      

       A44: o9 <> a29 & o9 <> a39 by A2, ZFMISC_1:def 6;

      

       A45: c2 on B1 by A8, INCSP_1: 2;

      

       A46: a2 on A1 by A7, INCSP_1: 2;

      then

       A47: (a29,b39,c19) are_collinear by A26, A19, Th10;

      

       A48: b1 <> b2 by A3, ZFMISC_1:def 6;

      

       A49: a1 <> a2 by A2, ZFMISC_1:def 6;

      

       A50: o <> b3 by A3, ZFMISC_1:def 6;

      

       A51: b1 on B1 by A8, INCSP_1: 2;

      then

       A52: (a39,b19,c29) are_collinear by A35, A45, Th10;

      

       A53: a3 on B3 by A14, INCSP_1: 2;

      then

       A54: (o9,a19,a39) are_collinear by A6, A27, Th10;

      

       A55: a2 on B3 by A14, INCSP_1: 2;

      then (o9,a19,a29) are_collinear by A6, A27, Th10;

      then (c19,c29,c39) are_collinear by A1, A44, A21, A43, A20, A25, A28, A54, A37, A42, A18, A34, A24, A52, A47, A40;

      then

       A56: ex K be LINE of ( IncProjSp_of CPS) st c1 on K & c2 on K & c3 on K by Th10;

      

       A57: o <> a3 by A2, ZFMISC_1:def 6;

      

       A58: c1 <> c2

      proof

        assume

         A59: not thesis;

         not a3 on A3 by A4, A5, A6, A57, A53, Th8;

        then B1 <> B2 by A48, A35, A51, A39, A16, A36, Th8;

        then

         A60: c1 = a3 by A35, A45, A38, A59, Th8;

         not b3 on B3 by A4, A5, A6, A50, A41, Th8;

        then A1 <> A2 by A49, A46, A26, A23, A27, A55, Th8;

        then c1 = b3 by A26, A19, A22, A59, Th8;

        hence contradiction by A4, A5, A6, A50, A41, A53, A60, Th8;

      end;

      c1 on C3 & c2 on C3 by A15, INCSP_1: 1;

      hence thesis by A58, A56, Th8;

    end;

    definition

      let S be IncProjStr;

      :: INCPROJ:def4

      attr S is partial means for p,q be POINT of S, P,Q be LINE of S st p on P & q on P & p on Q & q on Q holds p = q or P = Q;

      :: original: linear

      redefine

      :: INCPROJ:def5

      attr S is linear means for p,q be POINT of S holds ex P be LINE of S st p on P & q on P;

      compatibility

      proof

        hereby

          assume

           A1: S is linear;

          let p,q be POINT of S;

          consider P be LINE of S such that

           A2: {p, q} on P by A1;

          take P;

          thus p on P & q on P by A2, INCSP_1: 1;

        end;

        assume

         A3: for p,q be POINT of S holds ex P be LINE of S st p on P & q on P;

        let p,q be POINT of S;

        consider L be LINE of S such that

         A4: p on L & q on L by A3;

         {p, q} on L by A4, INCSP_1: 1;

        hence thesis;

      end;

    end

    definition

      let S be IncProjStr;

      :: INCPROJ:def6

      attr S is up-2-dimensional means ex p be POINT of S, P be LINE of S st not p on P;

      :: INCPROJ:def7

      attr S is up-3-rank means for P be LINE of S holds ex a,b,c be POINT of S st a <> b & b <> c & c <> a & a on P & b on P & c on P;

      :: INCPROJ:def8

      attr S is Vebleian means for a,b,c,d,p,q be POINT of S holds for M,N,P,Q be LINE of S st a on M & b on M & c on N & d on N & p on M & p on N & a on P & c on P & b on Q & d on Q & not p on P & not p on Q & M <> N holds ex q be POINT of S st q on P & q on Q;

    end

    registration

      let CPS be CollProjectiveSpace;

      cluster ( IncProjSp_of CPS) -> partial linear up-2-dimensional up-3-rank Vebleian;

      coherence by Th13, Th11, Th12, Th8, Th9;

    end

    registration

      cluster strict partial linear up-2-dimensional up-3-rank Vebleian for IncProjStr;

      existence

      proof

        set CPS = the CollProjectiveSpace;

        ( IncProjSp_of CPS) is strict partial linear up-2-dimensional up-3-rank Vebleian;

        hence thesis;

      end;

    end

    definition

      mode IncProjSp is partial linear up-2-dimensional up-3-rank Vebleian IncProjStr;

    end

    registration

      let CPS be CollProjectiveSpace;

      cluster ( IncProjSp_of CPS) -> partial linear up-2-dimensional up-3-rank Vebleian;

      coherence ;

    end

    definition

      let IT be IncProjSp;

      :: INCPROJ:def9

      attr IT is 2-dimensional means for M,N be LINE of IT holds ex q be POINT of IT st q on M & q on N;

    end

    notation

      let IT be IncProjSp;

      antonym IT is up-3-dimensional for IT is 2-dimensional;

    end

    definition

      let IT be IncProjStr;

      :: INCPROJ:def10

      attr IT is at_most-3-dimensional means for a be POINT of IT, M,N be LINE of IT holds ex b,c be POINT of IT, S be LINE of IT st a on S & b on S & c on S & b on M & c on N;

    end

    definition

      let IT be IncProjSp;

      :: INCPROJ:def11

      attr IT is 3-dimensional means IT is at_most-3-dimensional up-3-dimensional;

    end

    definition

      let IT be IncProjStr;

      :: INCPROJ:def12

      attr IT is Fanoian means for p,q,r,s,a,b,c be POINT of IT holds for L,Q,R,S,A,B,C be LINE of IT st not q on L & not r on L & not p on Q & not s on Q & not p on R & not r on R & not q on S & not s on S & {a, p, s} on L & {a, q, r} on Q & {b, q, s} on R & {b, p, r} on S & {c, p, q} on A & {c, r, s} on B & {a, b} on C holds not c on C;

    end

    definition

      let IT be IncProjStr;

      :: INCPROJ:def13

      attr IT is Desarguesian means for o,b1,a1,b2,a2,b3,a3,r,s,t be POINT of IT holds for C1,C2,C3,A1,A2,A3,B1,B2,B3 be LINE of IT st {o, b1, a1} on C1 & {o, a2, b2} on C2 & {o, a3, b3} on C3 & {a3, a2, t} on A1 & {a3, r, a1} on A2 & {a2, s, a1} on A3 & {t, b2, b3} on B1 & {b1, r, b3} on B2 & {b1, s, b2} on B3 & (C1,C2,C3) are_mutually_distinct & o <> a1 & o <> a2 & o <> a3 & o <> b1 & o <> b2 & o <> b3 & a1 <> b1 & a2 <> b2 & a3 <> b3 holds ex O be LINE of IT st {r, s, t} on O;

    end

    definition

      let IT be IncProjStr;

      :: INCPROJ:def14

      attr IT is Pappian means for o,a1,a2,a3,b1,b2,b3,c1,c2,c3 be POINT of IT holds for A1,A2,A3,B1,B2,B3,C1,C2,C3 be LINE of IT st (o,a1,a2,a3) are_mutually_distinct & (o,b1,b2,b3) are_mutually_distinct & A3 <> B3 & o on A3 & o on B3 & {a2, b3, c1} on A1 & {a3, b1, c2} on B1 & {a1, b2, c3} on C1 & {a1, b3, c2} on A2 & {a3, b2, c1} on B2 & {a2, b1, c3} on C2 & {b1, b2, b3} on A3 & {a1, a2, a3} on B3 & {c1, c2} on C3 holds c3 on C3;

    end

    registration

      cluster Desarguesian Fanoian at_most-3-dimensional up-3-dimensional for IncProjSp;

      existence

      proof

        set CPS = the Fanoian Desarguesian at_most-3-dimensional up-3-dimensional CollProjectiveSpace;

        reconsider CPS9 = CPS as CollProjectiveSpace;

        take X = ( IncProjSp_of CPS9);

        for o,p1,p2,p3,q1,q2,q3,r1,r2,r3 be Point of CPS9 st o <> q1 & p1 <> q1 & o <> q2 & p2 <> q2 & o <> q3 & p3 <> q3 & not (o,p1,p2) are_collinear & not (o,p1,p3) are_collinear & not (o,p2,p3) are_collinear & (p1,p2,r3) are_collinear & (q1,q2,r3) are_collinear & (p2,p3,r1) are_collinear & (q2,q3,r1) are_collinear & (p1,p3,r2) are_collinear & (q1,q3,r2) are_collinear & (o,p1,q1) are_collinear & (o,p2,q2) are_collinear & (o,p3,q3) are_collinear holds (r1,r2,r3) are_collinear by ANPROJ_2:def 12;

        then

         A1: for o,b1,a1,b2,a2,b3,a3,r,s,t be POINT of X holds for C1,C2,C3,A1,A2,A3,B1,B2,B3 be LINE of X st {o, b1, a1} on C1 & {o, a2, b2} on C2 & {o, a3, b3} on C3 & {a3, a2, t} on A1 & {a3, r, a1} on A2 & {a2, s, a1} on A3 & {t, b2, b3} on B1 & {b1, r, b3} on B2 & {b1, s, b2} on B3 & (C1,C2,C3) are_mutually_distinct & o <> a1 & o <> a2 & o <> a3 & o <> b1 & o <> b2 & o <> b3 & a1 <> b1 & a2 <> b2 & a3 <> b3 holds ex O be LINE of X st {r, s, t} on O by Th18;

        ex p,p1,r,r1 be Point of CPS9 st not ex s be Point of CPS9 st ((p,p1,s) are_collinear & (r,r1,s) are_collinear ) by ANPROJ_2:def 14;

        then

         A2: ex M,N be LINE of X st not ex q be POINT of X st q on M & q on N by Th15;

        for p,p1,q,q1,r2 be Point of CPS9 holds ex r,r1 be Point of CPS9 st (p,q,r) are_collinear & (p1,q1,r1) are_collinear & (r2,r,r1) are_collinear by ANPROJ_2:def 15;

        then

         A3: for a be POINT of X, M,N be LINE of X holds ex b,c be POINT of X, S be LINE of X st a on S & b on S & c on S & b on M & c on N by Th16;

        for p1,r2,q,r1,q1,p,r be Point of CPS9 holds ((p1,r2,q) are_collinear & (r1,q1,q) are_collinear & (p1,r1,p) are_collinear & (r2,q1,p) are_collinear & (p1,q1,r) are_collinear & (r2,r1,r) are_collinear & (p,q,r) are_collinear implies ((p1,r2,q1) are_collinear or (p1,r2,r1) are_collinear or (p1,r1,q1) are_collinear or (r2,r1,q1) are_collinear )) by ANPROJ_2:def 11;

        then for p,q,r,s,a,b,c be POINT of X holds for L,Q,R,S,A,B,C be LINE of X st not q on L & not r on L & not p on Q & not s on Q & not p on R & not r on R & not q on S & not s on S & {a, p, s} on L & {a, q, r} on Q & {b, q, s} on R & {b, p, r} on S & {c, p, q} on A & {c, r, s} on B & {a, b} on C holds not c on C by Th17;

        hence thesis by A1, A2, A3;

      end;

    end

    registration

      cluster Pappian Fanoian at_most-3-dimensional up-3-dimensional for IncProjSp;

      existence

      proof

        set CPS = the Fanoian Pappian at_most-3-dimensional up-3-dimensional CollProjectiveSpace;

        reconsider CPS9 = CPS as CollProjectiveSpace;

        take X = ( IncProjSp_of CPS9);

        for o,p1,p2,p3,q1,q2,q3,r1,r2,r3 be Point of CPS9 st o <> p2 & o <> p3 & p2 <> p3 & p1 <> p2 & p1 <> p3 & o <> q2 & o <> q3 & q2 <> q3 & q1 <> q2 & q1 <> q3 & not (o,p1,q1) are_collinear & (o,p1,p2) are_collinear & (o,p1,p3) are_collinear & (o,q1,q2) are_collinear & (o,q1,q3) are_collinear & (p1,q2,r3) are_collinear & (q1,p2,r3) are_collinear & (p1,q3,r2) are_collinear & (p3,q1,r2) are_collinear & (p2,q3,r1) are_collinear & (p3,q2,r1) are_collinear holds (r1,r2,r3) are_collinear by ANPROJ_2:def 13;

        then

         A1: for o,a1,a2,a3,b1,b2,b3,c1,c2,c3 be POINT of X holds for A1,A2,A3,B1,B2,B3,C1,C2,C3 be LINE of X st (o,a1,a2,a3) are_mutually_distinct & (o,b1,b2,b3) are_mutually_distinct & A3 <> B3 & o on A3 & o on B3 & {a2, b3, c1} on A1 & {a3, b1, c2} on B1 & {a1, b2, c3} on C1 & {a1, b3, c2} on A2 & {a3, b2, c1} on B2 & {a2, b1, c3} on C2 & {b1, b2, b3} on A3 & {a1, a2, a3} on B3 & {c1, c2} on C3 holds c3 on C3 by Th19;

        ex p,p1,r,r1 be Point of CPS9 st not ex s be Point of CPS9 st ((p,p1,s) are_collinear & (r,r1,s) are_collinear ) by ANPROJ_2:def 14;

        then

         A2: ex M,N be LINE of X st not ex q be POINT of X st q on M & q on N by Th15;

        for p,p1,q,q1,r2 be Point of CPS9 holds ex r,r1 be Point of CPS9 st (p,q,r) are_collinear & (p1,q1,r1) are_collinear & (r2,r,r1) are_collinear by ANPROJ_2:def 15;

        then

         A3: for a be POINT of X, M,N be LINE of X holds ex b,c be POINT of X, S be LINE of X st a on S & b on S & c on S & b on M & c on N by Th16;

        for p1,r2,q,r1,q1,p,r be Point of CPS9 holds ((p1,r2,q) are_collinear & (r1,q1,q) are_collinear & (p1,r1,p) are_collinear & (r2,q1,p) are_collinear & (p1,q1,r) are_collinear & (r2,r1,r) are_collinear & (p,q,r) are_collinear implies ((p1,r2,q1) are_collinear or (p1,r2,r1) are_collinear or (p1,r1,q1) are_collinear or (r2,r1,q1) are_collinear )) by ANPROJ_2:def 11;

        then for p,q,r,s,a,b,c be POINT of X holds for L,Q,R,S,A,B,C be LINE of X st not q on L & not r on L & not p on Q & not s on Q & not p on R & not r on R & not q on S & not s on S & {a, p, s} on L & {a, q, r} on Q & {b, q, s} on R & {b, p, r} on S & {c, p, q} on A & {c, r, s} on B & {a, b} on C holds not c on C by Th17;

        hence thesis by A1, A2, A3;

      end;

    end

    registration

      cluster Desarguesian Fanoian 2-dimensional for IncProjSp;

      existence

      proof

        set CPS = the Fanoian Desarguesian CollProjectivePlane;

        reconsider CPS9 = CPS as CollProjectiveSpace;

        take X = ( IncProjSp_of CPS9);

        for o,p1,p2,p3,q1,q2,q3,r1,r2,r3 be Point of CPS9 st o <> q1 & p1 <> q1 & o <> q2 & p2 <> q2 & o <> q3 & p3 <> q3 & not (o,p1,p2) are_collinear & not (o,p1,p3) are_collinear & not (o,p2,p3) are_collinear & (p1,p2,r3) are_collinear & (q1,q2,r3) are_collinear & (p2,p3,r1) are_collinear & (q2,q3,r1) are_collinear & (p1,p3,r2) are_collinear & (q1,q3,r2) are_collinear & (o,p1,q1) are_collinear & (o,p2,q2) are_collinear & (o,p3,q3) are_collinear holds (r1,r2,r3) are_collinear by ANPROJ_2:def 12;

        then

         A1: for o,b1,a1,b2,a2,b3,a3,r,s,t be POINT of X holds for C1,C2,C3,A1,A2,A3,B1,B2,B3 be LINE of X st {o, b1, a1} on C1 & {o, a2, b2} on C2 & {o, a3, b3} on C3 & {a3, a2, t} on A1 & {a3, r, a1} on A2 & {a2, s, a1} on A3 & {t, b2, b3} on B1 & {b1, r, b3} on B2 & {b1, s, b2} on B3 & (C1,C2,C3) are_mutually_distinct & o <> a1 & o <> a2 & o <> a3 & o <> b1 & o <> b2 & o <> b3 & a1 <> b1 & a2 <> b2 & a3 <> b3 holds ex O be LINE of X st {r, s, t} on O by Th18;

        for a,b,c,d be Point of CPS9 holds ex p be Point of CPS9 st (a,b,p) are_collinear & (c,d,p) are_collinear by ANPROJ_2:def 14;

        then

         A2: for M,N be LINE of X holds ex q be POINT of X st q on M & q on N by Th14;

        for p1,r2,q,r1,q1,p,r be Point of CPS9 holds ((p1,r2,q) are_collinear & (r1,q1,q) are_collinear & (p1,r1,p) are_collinear & (r2,q1,p) are_collinear & (p1,q1,r) are_collinear & (r2,r1,r) are_collinear & (p,q,r) are_collinear implies ((p1,r2,q1) are_collinear or (p1,r2,r1) are_collinear or (p1,r1,q1) are_collinear or (r2,r1,q1) are_collinear )) by ANPROJ_2:def 11;

        then for p,q,r,s,a,b,c be POINT of X holds for L,Q,R,S,A,B,C be LINE of X st not q on L & not r on L & not p on Q & not s on Q & not p on R & not r on R & not q on S & not s on S & {a, p, s} on L & {a, q, r} on Q & {b, q, s} on R & {b, p, r} on S & {c, p, q} on A & {c, r, s} on B & {a, b} on C holds not c on C by Th17;

        hence thesis by A1, A2;

      end;

    end

    registration

      cluster Pappian Fanoian 2-dimensional for IncProjSp;

      existence

      proof

        set CPS = the Fanoian Pappian CollProjectivePlane;

        reconsider CPS9 = CPS as CollProjectiveSpace;

        take X = ( IncProjSp_of CPS9);

        for o,p1,p2,p3,q1,q2,q3,r1,r2,r3 be Point of CPS9 st o <> p2 & o <> p3 & p2 <> p3 & p1 <> p2 & p1 <> p3 & o <> q2 & o <> q3 & q2 <> q3 & q1 <> q2 & q1 <> q3 & not (o,p1,q1) are_collinear & (o,p1,p2) are_collinear & (o,p1,p3) are_collinear & (o,q1,q2) are_collinear & (o,q1,q3) are_collinear & (p1,q2,r3) are_collinear & (q1,p2,r3) are_collinear & (p1,q3,r2) are_collinear & (p3,q1,r2) are_collinear & (p2,q3,r1) are_collinear & (p3,q2,r1) are_collinear holds (r1,r2,r3) are_collinear by ANPROJ_2:def 13;

        then

         A1: for o,a1,a2,a3,b1,b2,b3,c1,c2,c3 be POINT of X holds for A1,A2,A3,B1,B2,B3,C1,C2,C3 be LINE of X st (o,a1,a2,a3) are_mutually_distinct & (o,b1,b2,b3) are_mutually_distinct & A3 <> B3 & o on A3 & o on B3 & {a2, b3, c1} on A1 & {a3, b1, c2} on B1 & {a1, b2, c3} on C1 & {a1, b3, c2} on A2 & {a3, b2, c1} on B2 & {a2, b1, c3} on C2 & {b1, b2, b3} on A3 & {a1, a2, a3} on B3 & {c1, c2} on C3 holds c3 on C3 by Th19;

        for a,b,c,d be Point of CPS9 holds ex p be Point of CPS9 st (a,b,p) are_collinear & (c,d,p) are_collinear by ANPROJ_2:def 14;

        then

         A2: for M,N be LINE of X holds ex q be POINT of X st q on M & q on N by Th14;

        for p1,r2,q,r1,q1,p,r be Point of CPS9 holds ((p1,r2,q) are_collinear & (r1,q1,q) are_collinear & (p1,r1,p) are_collinear & (r2,q1,p) are_collinear & (p1,q1,r) are_collinear & (r2,r1,r) are_collinear & (p,q,r) are_collinear implies ((p1,r2,q1) are_collinear or (p1,r2,r1) are_collinear or (p1,r1,q1) are_collinear or (r2,r1,q1) are_collinear )) by ANPROJ_2:def 11;

        then for p,q,r,s,a,b,c be POINT of X holds for L,Q,R,S,A,B,C be LINE of X st not q on L & not r on L & not p on Q & not s on Q & not p on R & not r on R & not q on S & not s on S & {a, p, s} on L & {a, q, r} on Q & {b, q, s} on R & {b, p, r} on S & {c, p, q} on A & {c, r, s} on B & {a, b} on C holds not c on C by Th17;

        hence thesis by A1, A2;

      end;

    end