yellow_3.miz
    
    begin
    
    scheme :: 
    
    YELLOW_3:sch1
    
    FraenkelA2 { A() -> non
    empty  
    set , F( 
    set, 
    set) ->
    set , P[ 
    set, 
    set], Q[
    set, 
    set] } :
    
{ F(s,t) where s be 
    Element of A(), t be 
    Element of A() : P[s, t] } is 
    Subset of A() 
    
      provided
    
      
    
    A1: for s be 
    Element of A(), t be 
    Element of A() holds F(s,t) 
    in A(); 
    
      { F(s,t) where s be
    Element of A(), t be 
    Element of A() : P[s, t] } 
    c= A() 
    
      proof
    
        let q be
    object;
    
        assume q
    in { F(s,t) where s be 
    Element of A(), t be 
    Element of A() : P[s, t] }; 
    
        then ex s,t be
    Element of A() st q 
    = F(s,t) & P[s, t]; 
    
        hence thesis by
    A1;
    
      end;
    
      hence thesis;
    
    end;
    
    registration
    
      let L be
    RelStr, X be 
    empty  
    Subset of L; 
    
      cluster ( 
    downarrow X) -> 
    empty;
    
      coherence
    
      proof
    
        assume (
    downarrow X) is non 
    empty;
    
        then
    
        consider x be
    object such that 
    
        
    
    A1: x 
    in ( 
    downarrow X) by 
    XBOOLE_0:def 1;
    
        reconsider x as
    Element of L by 
    A1;
    
        ex z be
    Element of L st x 
    <= z & z 
    in X by 
    A1,
    WAYBEL_0:def 15;
    
        hence contradiction;
    
      end;
    
      cluster ( 
    uparrow X) -> 
    empty;
    
      coherence
    
      proof
    
        assume (
    uparrow X) is non 
    empty;
    
        then
    
        consider x be
    object such that 
    
        
    
    A2: x 
    in ( 
    uparrow X) by 
    XBOOLE_0:def 1;
    
        reconsider x as
    Element of L by 
    A2;
    
        ex z be
    Element of L st z 
    <= x & z 
    in X by 
    A2,
    WAYBEL_0:def 16;
    
        hence contradiction;
    
      end;
    
    end
    
    theorem :: 
    
    YELLOW_3:1
    
    
    
    
    
    Th1: for X,Y be 
    set, D be 
    Subset of 
    [:X, Y:] holds D
    c=  
    [:(
    proj1 D), ( 
    proj2 D):] 
    
    proof
    
      let X,Y be
    set, D be 
    Subset of 
    [:X, Y:];
    
      let q be
    object;
    
      assume
    
      
    
    A1: q 
    in D; 
    
      then
    
      consider x,y be
    object such that x 
    in X and y 
    in Y and 
    
      
    
    A2: q 
    =  
    [x, y] by
    ZFMISC_1:def 2;
    
      x
    in ( 
    proj1 D) & y 
    in ( 
    proj2 D) by 
    A1,
    A2,
    XTUPLE_0:def 12,
    XTUPLE_0:def 13;
    
      hence thesis by
    A2,
    ZFMISC_1:def 2;
    
    end;
    
    theorem :: 
    
    YELLOW_3:2
    
    for L be
    with_infima
    transitive
    antisymmetric  
    RelStr holds for a,b,c,d be 
    Element of L st a 
    <= c & b 
    <= d holds (a 
    "/\" b) 
    <= (c 
    "/\" d) 
    
    proof
    
      let L be
    with_infima
    transitive
    antisymmetric  
    RelStr, a,b,c,d be 
    Element of L such that 
    
      
    
    A1: a 
    <= c and 
    
      
    
    A2: b 
    <= d; 
    
      
    
      
    
    A3: 
    ex_inf_of ( 
    {a, b},L) by
    YELLOW_0: 21;
    
      then (a
    "/\" b) 
    <= b by 
    YELLOW_0: 19;
    
      then
    
      
    
    A4: (a 
    "/\" b) 
    <= d by 
    A2,
    ORDERS_2: 3;
    
      (a
    "/\" b) 
    <= a by 
    A3,
    YELLOW_0: 19;
    
      then (ex x be
    Element of L st c 
    >= x & d 
    >= x & for z be 
    Element of L st c 
    >= z & d 
    >= z holds x 
    >= z) & (a 
    "/\" b) 
    <= c by 
    A1,
    LATTICE3:def 11,
    ORDERS_2: 3;
    
      hence thesis by
    A4,
    LATTICE3:def 14;
    
    end;
    
    theorem :: 
    
    YELLOW_3:3
    
    for L be
    with_suprema
    transitive
    antisymmetric  
    RelStr holds for a,b,c,d be 
    Element of L st a 
    <= c & b 
    <= d holds (a 
    "\/" b) 
    <= (c 
    "\/" d) 
    
    proof
    
      let L be
    with_suprema
    transitive
    antisymmetric  
    RelStr, a,b,c,d be 
    Element of L such that 
    
      
    
    A1: a 
    <= c and 
    
      
    
    A2: b 
    <= d; 
    
      
    
      
    
    A3: 
    ex_sup_of ( 
    {c, d},L) by
    YELLOW_0: 20;
    
      then d
    <= (c 
    "\/" d) by 
    YELLOW_0: 18;
    
      then
    
      
    
    A4: b 
    <= (c 
    "\/" d) by 
    A2,
    ORDERS_2: 3;
    
      c
    <= (c 
    "\/" d) by 
    A3,
    YELLOW_0: 18;
    
      then (ex x be
    Element of L st a 
    <= x & b 
    <= x & for z be 
    Element of L st a 
    <= z & b 
    <= z holds x 
    <= z) & a 
    <= (c 
    "\/" d) by 
    A1,
    LATTICE3:def 10,
    ORDERS_2: 3;
    
      hence thesis by
    A4,
    LATTICE3:def 13;
    
    end;
    
    theorem :: 
    
    YELLOW_3:4
    
    for L be
    complete
    reflexive
    antisymmetric non 
    empty  
    RelStr holds for D be 
    Subset of L, x be 
    Element of L st x 
    in D holds (( 
    sup D) 
    "/\" x) 
    = x 
    
    proof
    
      let L be
    complete
    reflexive
    antisymmetric non 
    empty  
    RelStr, D be 
    Subset of L, x be 
    Element of L such that 
    
      
    
    A1: x 
    in D; 
    
      D
    is_<=_than ( 
    sup D) by 
    YELLOW_0: 32;
    
      then x
    <= ( 
    sup D) by 
    A1;
    
      hence thesis by
    YELLOW_0: 25;
    
    end;
    
    theorem :: 
    
    YELLOW_3:5
    
    for L be
    complete
    reflexive
    antisymmetric non 
    empty  
    RelStr holds for D be 
    Subset of L, x be 
    Element of L st x 
    in D holds (( 
    inf D) 
    "\/" x) 
    = x 
    
    proof
    
      let L be
    complete
    reflexive
    antisymmetric non 
    empty  
    RelStr, D be 
    Subset of L, x be 
    Element of L such that 
    
      
    
    A1: x 
    in D; 
    
      D
    is_>=_than ( 
    inf D) by 
    YELLOW_0: 33;
    
      then (
    inf D) 
    <= x by 
    A1;
    
      hence thesis by
    YELLOW_0: 24;
    
    end;
    
    theorem :: 
    
    YELLOW_3:6
    
    for L be
    RelStr, X,Y be 
    Subset of L st X 
    c= Y holds ( 
    downarrow X) 
    c= ( 
    downarrow Y) 
    
    proof
    
      let L be
    RelStr, X,Y be 
    Subset of L such that 
    
      
    
    A1: X 
    c= Y; 
    
      let q be
    object;
    
      assume
    
      
    
    A2: q 
    in ( 
    downarrow X); 
    
      then
    
      reconsider x = q as
    Element of L; 
    
      ex z be
    Element of L st x 
    <= z & z 
    in X by 
    A2,
    WAYBEL_0:def 15;
    
      hence thesis by
    A1,
    WAYBEL_0:def 15;
    
    end;
    
    theorem :: 
    
    YELLOW_3:7
    
    for L be
    RelStr, X,Y be 
    Subset of L st X 
    c= Y holds ( 
    uparrow X) 
    c= ( 
    uparrow Y) 
    
    proof
    
      let L be
    RelStr, X,Y be 
    Subset of L such that 
    
      
    
    A1: X 
    c= Y; 
    
      let q be
    object;
    
      assume
    
      
    
    A2: q 
    in ( 
    uparrow X); 
    
      then
    
      reconsider x = q as
    Element of L; 
    
      ex z be
    Element of L st z 
    <= x & z 
    in X by 
    A2,
    WAYBEL_0:def 16;
    
      hence thesis by
    A1,
    WAYBEL_0:def 16;
    
    end;
    
    theorem :: 
    
    YELLOW_3:8
    
    for S,T be
    with_infima  
    Poset, f be 
    Function of S, T holds for x,y be 
    Element of S holds f 
    preserves_inf_of  
    {x, y} iff (f
    . (x 
    "/\" y)) 
    = ((f 
    . x) 
    "/\" (f 
    . y)) 
    
    proof
    
      let S,T be
    with_infima  
    Poset, f be 
    Function of S, T, x,y be 
    Element of S; 
    
      
    
      
    
    A1: ( 
    dom f) 
    = the 
    carrier of S by 
    FUNCT_2:def 1;
    
      hereby
    
        
    
        
    
    A2: 
    ex_inf_of ( 
    {x, y},S) by
    YELLOW_0: 21;
    
        assume
    
        
    
    A3: f 
    preserves_inf_of  
    {x, y};
    
        
    
        thus (f
    . (x 
    "/\" y)) 
    = (f 
    . ( 
    inf  
    {x, y})) by
    YELLOW_0: 40
    
        .= (
    inf (f 
    .:  
    {x, y})) by
    A3,
    A2
    
        .= (
    inf  
    {(f
    . x), (f 
    . y)}) by 
    A1,
    FUNCT_1: 60
    
        .= ((f
    . x) 
    "/\" (f 
    . y)) by 
    YELLOW_0: 40;
    
      end;
    
      assume
    
      
    
    A4: (f 
    . (x 
    "/\" y)) 
    = ((f 
    . x) 
    "/\" (f 
    . y)); 
    
      assume
    ex_inf_of ( 
    {x, y},S);
    
      (f
    .:  
    {x, y})
    =  
    {(f
    . x), (f 
    . y)} by 
    A1,
    FUNCT_1: 60;
    
      hence
    ex_inf_of ((f 
    .:  
    {x, y}),T) by
    YELLOW_0: 21;
    
      
    
      thus (
    inf (f 
    .:  
    {x, y}))
    = ( 
    inf  
    {(f
    . x), (f 
    . y)}) by 
    A1,
    FUNCT_1: 60
    
      .= ((f
    . x) 
    "/\" (f 
    . y)) by 
    YELLOW_0: 40
    
      .= (f
    . ( 
    inf  
    {x, y})) by
    A4,
    YELLOW_0: 40;
    
    end;
    
    theorem :: 
    
    YELLOW_3:9
    
    for S,T be
    with_suprema  
    Poset, f be 
    Function of S, T holds for x,y be 
    Element of S holds f 
    preserves_sup_of  
    {x, y} iff (f
    . (x 
    "\/" y)) 
    = ((f 
    . x) 
    "\/" (f 
    . y)) 
    
    proof
    
      let S,T be
    with_suprema  
    Poset, f be 
    Function of S, T, x,y be 
    Element of S; 
    
      
    
      
    
    A1: ( 
    dom f) 
    = the 
    carrier of S by 
    FUNCT_2:def 1;
    
      hereby
    
        
    
        
    
    A2: 
    ex_sup_of ( 
    {x, y},S) by
    YELLOW_0: 20;
    
        assume
    
        
    
    A3: f 
    preserves_sup_of  
    {x, y};
    
        
    
        thus (f
    . (x 
    "\/" y)) 
    = (f 
    . ( 
    sup  
    {x, y})) by
    YELLOW_0: 41
    
        .= (
    sup (f 
    .:  
    {x, y})) by
    A3,
    A2
    
        .= (
    sup  
    {(f
    . x), (f 
    . y)}) by 
    A1,
    FUNCT_1: 60
    
        .= ((f
    . x) 
    "\/" (f 
    . y)) by 
    YELLOW_0: 41;
    
      end;
    
      assume
    
      
    
    A4: (f 
    . (x 
    "\/" y)) 
    = ((f 
    . x) 
    "\/" (f 
    . y)); 
    
      assume
    ex_sup_of ( 
    {x, y},S);
    
      (f
    .:  
    {x, y})
    =  
    {(f
    . x), (f 
    . y)} by 
    A1,
    FUNCT_1: 60;
    
      hence
    ex_sup_of ((f 
    .:  
    {x, y}),T) by
    YELLOW_0: 20;
    
      
    
      thus (
    sup (f 
    .:  
    {x, y}))
    = ( 
    sup  
    {(f
    . x), (f 
    . y)}) by 
    A1,
    FUNCT_1: 60
    
      .= ((f
    . x) 
    "\/" (f 
    . y)) by 
    YELLOW_0: 41
    
      .= (f
    . ( 
    sup  
    {x, y})) by
    A4,
    YELLOW_0: 41;
    
    end;
    
    scheme :: 
    
    YELLOW_3:sch2
    
    InfUnion { L() ->
    complete
    antisymmetric non 
    empty  
    RelStr , P[ 
    set] } :
    
(
    "/\" ({ ( 
    "/\" (X,L())) where X be 
    Subset of L() : P[X] },L())) 
    >= ( 
    "/\" (( 
    union { X where X be 
    Subset of L() : P[X] }),L())); 
    
      (
    "/\" (( 
    union { X where X be 
    Subset of L() : P[X] }),L())) 
    is_<=_than { ( 
    "/\" (X,L())) where X be 
    Subset of L() : P[X] } 
    
      proof
    
        let a be
    Element of L(); 
    
        assume a
    in { ( 
    "/\" (X,L())) where X be 
    Subset of L() : P[X] }; 
    
        then
    
        consider q be
    Subset of L() such that 
    
        
    
    A1: a 
    = ( 
    "/\" (q,L())) and 
    
        
    
    A2: P[q]; 
    
        
    
        
    
    A3: 
    ex_inf_of (q,L()) & 
    ex_inf_of (( 
    union { X where X be 
    Subset of L() : P[X] }),L()) by 
    YELLOW_0: 17;
    
        q
    in { X where X be 
    Subset of L() : P[X] } by 
    A2;
    
        hence thesis by
    A1,
    A3,
    YELLOW_0: 35,
    ZFMISC_1: 74;
    
      end;
    
      hence thesis by
    YELLOW_0: 33;
    
    end;
    
    scheme :: 
    
    YELLOW_3:sch3
    
    InfofInfs { L() ->
    complete  
    LATTICE , P[ 
    set] } :
    
(
    "/\" ({ ( 
    "/\" (X,L())) where X be 
    Subset of L() : P[X] },L())) 
    = ( 
    "/\" (( 
    union { X where X be 
    Subset of L() : P[X] }),L())); 
    
      (
    union { X where X be 
    Subset of L() : P[X] }) 
    is_>=_than ( 
    "/\" ({ ( 
    "/\" (X,L())) where X be 
    Subset of L() : P[X] },L())) 
    
      proof
    
        let a be
    Element of L(); 
    
        assume a
    in ( 
    union { X where X be 
    Subset of L() : P[X] }); 
    
        then
    
        consider b be
    set such that 
    
        
    
    A1: a 
    in b and 
    
        
    
    A2: b 
    in { X where X be 
    Subset of L() : P[X] } by 
    TARSKI:def 4;
    
        consider c be
    Subset of L() such that 
    
        
    
    A3: b 
    = c and 
    
        
    
    A4: P[c] by 
    A2;
    
        (
    "/\" (c,L())) 
    in { ( 
    "/\" (X,L())) where X be 
    Subset of L() : P[X] } by 
    A4;
    
        then
    
        
    
    A5: ( 
    "/\" (c,L())) 
    >= ( 
    "/\" ({ ( 
    "/\" (X,L())) where X be 
    Subset of L() : P[X] },L())) by 
    YELLOW_2: 22;
    
        (
    "/\" (c,L())) 
    <= a by 
    A1,
    A3,
    YELLOW_2: 22;
    
        hence thesis by
    A5,
    YELLOW_0:def 2;
    
      end;
    
      then
    
      
    
    A6: ( 
    "/\" (( 
    union { X where X be 
    Subset of L() : P[X] }),L())) 
    >= ( 
    "/\" ({ ( 
    "/\" (X,L())) where X be 
    Subset of L() : P[X] },L())) by 
    YELLOW_0: 33;
    
      (
    "/\" ({ ( 
    "/\" (X,L())) where X be 
    Subset of L() : P[X] },L())) 
    >= ( 
    "/\" (( 
    union { X where X be 
    Subset of L() : P[X] }),L())) from 
    InfUnion;
    
      hence thesis by
    A6,
    ORDERS_2: 2;
    
    end;
    
    scheme :: 
    
    YELLOW_3:sch4
    
    SupUnion { L() ->
    complete
    antisymmetric non 
    empty  
    RelStr , P[ 
    set] } :
    
(
    "\/" ({ ( 
    "\/" (X,L())) where X be 
    Subset of L() : P[X] },L())) 
    <= ( 
    "\/" (( 
    union { X where X be 
    Subset of L() : P[X] }),L())); 
    
      
    
      
    
    A1: ( 
    "\/" (( 
    union { X where X be 
    Subset of L() : P[X] }),L())) 
    is_>=_than { ( 
    "\/" (X,L())) where X be 
    Subset of L() : P[X] } 
    
      proof
    
        let a be
    Element of L(); 
    
        assume a
    in { ( 
    "\/" (X,L())) where X be 
    Subset of L() : P[X] }; 
    
        then
    
        consider q be
    Subset of L() such that 
    
        
    
    A2: a 
    = ( 
    "\/" (q,L())) and 
    
        
    
    A3: P[q]; 
    
        
    
        
    
    A4: 
    ex_sup_of (q,L()) & 
    ex_sup_of (( 
    union { X where X be 
    Subset of L() : P[X] }),L()) by 
    YELLOW_0: 17;
    
        q
    in { X where X be 
    Subset of L() : P[X] } by 
    A3;
    
        hence thesis by
    A2,
    A4,
    YELLOW_0: 34,
    ZFMISC_1: 74;
    
      end;
    
      
    ex_sup_of ({ ( 
    "\/" (X,L())) where X be 
    Subset of L() : P[X] },L()) by 
    YELLOW_0: 17;
    
      hence thesis by
    A1,
    YELLOW_0:def 9;
    
    end;
    
    scheme :: 
    
    YELLOW_3:sch5
    
    SupofSups { L() ->
    complete  
    LATTICE , P[ 
    set] } :
    
(
    "\/" ({ ( 
    "\/" (X,L())) where X be 
    Subset of L() : P[X] },L())) 
    = ( 
    "\/" (( 
    union { X where X be 
    Subset of L() : P[X] }),L())); 
    
      
    
      
    
    A1: ( 
    union { X where X be 
    Subset of L() : P[X] }) 
    is_<=_than ( 
    "\/" ({ ( 
    "\/" (X,L())) where X be 
    Subset of L() : P[X] },L())) 
    
      proof
    
        let a be
    Element of L(); 
    
        assume a
    in ( 
    union { X where X be 
    Subset of L() : P[X] }); 
    
        then
    
        consider b be
    set such that 
    
        
    
    A2: a 
    in b and 
    
        
    
    A3: b 
    in { X where X be 
    Subset of L() : P[X] } by 
    TARSKI:def 4;
    
        consider c be
    Subset of L() such that 
    
        
    
    A4: b 
    = c and 
    
        
    
    A5: P[c] by 
    A3;
    
        (
    "\/" (c,L())) 
    in { ( 
    "\/" (X,L())) where X be 
    Subset of L() : P[X] } by 
    A5;
    
        then
    
        
    
    A6: ( 
    "\/" (c,L())) 
    <= ( 
    "\/" ({ ( 
    "\/" (X,L())) where X be 
    Subset of L() : P[X] },L())) by 
    YELLOW_2: 22;
    
        a
    <= ( 
    "\/" (c,L())) by 
    A2,
    A4,
    YELLOW_2: 22;
    
        hence a
    <= ( 
    "\/" ({ ( 
    "\/" (X,L())) where X be 
    Subset of L() : P[X] },L())) by 
    A6,
    YELLOW_0:def 2;
    
      end;
    
      
    
      
    
    A7: ( 
    "\/" ({ ( 
    "\/" (X,L())) where X be 
    Subset of L() : P[X] },L())) 
    <= ( 
    "\/" (( 
    union { X where X be 
    Subset of L() : P[X] }),L())) from 
    SupUnion;
    
      
    ex_sup_of (( 
    union { X where X be 
    Subset of L() : P[X] }),L()) by 
    YELLOW_0: 17;
    
      then (
    "\/" (( 
    union { X where X be 
    Subset of L() : P[X] }),L())) 
    <= ( 
    "\/" ({ ( 
    "\/" (X,L())) where X be 
    Subset of L() : P[X] },L())) by 
    A1,
    YELLOW_0:def 9;
    
      hence thesis by
    A7,
    ORDERS_2: 2;
    
    end;
    
    begin
    
    definition
    
      let P,R be
    Relation;
    
      :: 
    
    YELLOW_3:def1
    
      func
    
    ["P,R"] ->
    Relation means 
    
      :
    
    Def1: for x,y be 
    object holds 
    [x, y]
    in it iff ex p,q,s,t be 
    object st x 
    =  
    [p, q] & y
    =  
    [s, t] &
    [p, s]
    in P & 
    [q, t]
    in R; 
    
      existence
    
      proof
    
        defpred
    
    P[
    object, 
    object] means ex p,s,q,t be
    object st $1 
    =  
    [p, q] & $2
    =  
    [s, t] &
    [p, s]
    in P & 
    [q, t]
    in R; 
    
        consider Q be
    Relation such that 
    
        
    
    A1: for x,y be 
    object holds 
    [x, y]
    in Q iff x 
    in  
    [:(
    dom P), ( 
    dom R):] & y 
    in  
    [:(
    rng P), ( 
    rng R):] & 
    P[x, y] from
    RELAT_1:sch 1;
    
        take Q;
    
        let x,y be
    object;
    
        hereby
    
          assume
    [x, y]
    in Q; 
    
          then
    
          consider p,s,q,t be
    object such that 
    
          
    
    A2: x 
    =  
    [p, q] & y
    =  
    [s, t] &
    [p, s]
    in P & 
    [q, t]
    in R by 
    A1;
    
          take p, q, s, t;
    
          thus x
    =  
    [p, q] & y
    =  
    [s, t] &
    [p, s]
    in P & 
    [q, t]
    in R by 
    A2;
    
        end;
    
        given p,q,s,t be
    object such that 
    
        
    
    A3: x 
    =  
    [p, q] and
    
        
    
    A4: y 
    =  
    [s, t] and
    
        
    
    A5: 
    [p, s]
    in P & 
    [q, t]
    in R; 
    
        s
    in ( 
    rng P) & t 
    in ( 
    rng R) by 
    A5,
    XTUPLE_0:def 13;
    
        then
    
        
    
    A6: y 
    in  
    [:(
    rng P), ( 
    rng R):] by 
    A4,
    ZFMISC_1: 87;
    
        p
    in ( 
    dom P) & q 
    in ( 
    dom R) by 
    A5,
    XTUPLE_0:def 12;
    
        then x
    in  
    [:(
    dom P), ( 
    dom R):] by 
    A3,
    ZFMISC_1: 87;
    
        hence thesis by
    A1,
    A3,
    A4,
    A5,
    A6;
    
      end;
    
      uniqueness
    
      proof
    
        defpred
    
    P[
    object, 
    object] means ex p,q,s,t be
    object st $1 
    =  
    [p, q] & $2
    =  
    [s, t] &
    [p, s]
    in P & 
    [q, t]
    in R; 
    
        let A,B be
    Relation such that 
    
        
    
    A7: for x,y be 
    object holds 
    [x, y]
    in A iff 
    P[x, y] and
    
        
    
    A8: for x,y be 
    object holds 
    [x, y]
    in B iff 
    P[x, y];
    
        thus A
    = B from 
    RELAT_1:sch 2(
    A7,
    A8);
    
      end;
    
    end
    
    theorem :: 
    
    YELLOW_3:10
    
    
    
    
    
    Th10: for P,R be 
    Relation, x be 
    object holds x 
    in  
    ["P, R"] iff
    [((x
    `1 ) 
    `1 ), ((x 
    `2 ) 
    `1 )] 
    in P & 
    [((x
    `1 ) 
    `2 ), ((x 
    `2 ) 
    `2 )] 
    in R & (ex a,b be 
    object st x 
    =  
    [a, b]) & (ex c,d be
    object st (x 
    `1 ) 
    =  
    [c, d]) & ex e,f be
    object st (x 
    `2 ) 
    =  
    [e, f]
    
    proof
    
      let P,R be
    Relation, x be 
    object;
    
      hereby
    
        assume
    
        
    
    A1: x 
    in  
    ["P, R"];
    
        then
    
        consider y,z be
    object such that 
    
        
    
    A2: x 
    =  
    [y, z] by
    RELAT_1:def 1;
    
        consider p,q,s,t be
    object such that 
    
        
    
    A3: y 
    =  
    [p, q] and
    
        
    
    A4: z 
    =  
    [s, t] and
    
        
    
    A5: 
    [p, s]
    in P & 
    [q, t]
    in R by 
    A1,
    A2,
    Def1;
    
        ((x
    `1 ) 
    `1 ) 
    = p & ((x 
    `1 ) 
    `2 ) 
    = q by 
    A2,
    A3;
    
        hence
    [((x
    `1 ) 
    `1 ), ((x 
    `2 ) 
    `1 )] 
    in P & 
    [((x
    `1 ) 
    `2 ), ((x 
    `2 ) 
    `2 )] 
    in R by 
    A2,
    A4,
    A5;
    
        thus ex a,b be
    object st x 
    =  
    [a, b] by
    A2;
    
        thus ex c,d be
    object st (x 
    `1 ) 
    =  
    [c, d] by
    A2,
    A3;
    
        thus ex e,f be
    object st (x 
    `2 ) 
    =  
    [e, f] by
    A2,
    A4;
    
      end;
    
      assume that
    
      
    
    A6: 
    [((x
    `1 ) 
    `1 ), ((x 
    `2 ) 
    `1 )] 
    in P and 
    
      
    
    A7: 
    [((x
    `1 ) 
    `2 ), ((x 
    `2 ) 
    `2 )] 
    in R; 
    
      given a,b be
    object such that 
    
      
    
    A8: x 
    =  
    [a, b];
    
      given c,d be
    object such that 
    
      
    
    A9: (x 
    `1 ) 
    =  
    [c, d];
    
      given e,f be
    object such that 
    
      
    
    A10: (x 
    `2 ) 
    =  
    [e, f];
    
      
    [c, ((x
    `2 ) 
    `1 )] 
    in P by 
    A6,
    A9;
    
      then
    
      
    
    A11: 
    [c, e]
    in P by 
    A10;
    
      
    [d, ((x
    `2 ) 
    `2 )] 
    in R by 
    A7,
    A9;
    
      then
    
      
    
    A12: 
    [d, f]
    in R by 
    A10;
    
      
    
      
    
    A13: b 
    =  
    [e, f] by
    A8,
    A10;
    
      a
    =  
    [c, d] by
    A8,
    A9;
    
      hence thesis by
    A8,
    A13,
    A11,
    A12,
    Def1;
    
    end;
    
    definition
    
      let A,B,X,Y be
    set;
    
      let P be
    Relation of A, B; 
    
      let R be
    Relation of X, Y; 
    
      :: original:
    ["
    
      redefine
    
      func
    
    ["P,R"] ->
    Relation of 
    [:A, X:],
    [:B, Y:] ;
    
      coherence
    
      proof
    
        
    ["P, R"]
    c=  
    [:
    [:A, X:],
    [:B, Y:]:]
    
        proof
    
          let q be
    object;
    
          assume
    
          
    
    A1: q 
    in  
    ["P, R"];
    
          then
    
          consider a,b be
    object such that 
    
          
    
    A2: q 
    =  
    [a, b] by
    Th10;
    
          
    [((q
    `1 ) 
    `2 ), ((q 
    `2 ) 
    `2 )] 
    in R by 
    A1,
    Th10;
    
          then
    
          consider s,t be
    object such that 
    
          
    
    A3: 
    [((q
    `1 ) 
    `2 ), ((q 
    `2 ) 
    `2 )] 
    =  
    [s, t] and
    
          
    
    A4: s 
    in X and 
    
          
    
    A5: t 
    in Y by 
    RELSET_1: 2;
    
          consider a2,b2 be
    object such that 
    
          
    
    A6: (q 
    `2 ) 
    =  
    [a2, b2] by
    A1,
    Th10;
    
          
    [((q
    `1 ) 
    `1 ), ((q 
    `2 ) 
    `1 )] 
    in P by 
    A1,
    Th10;
    
          then
    
          consider x,y be
    object such that 
    
          
    
    A7: 
    [((q
    `1 ) 
    `1 ), ((q 
    `2 ) 
    `1 )] 
    =  
    [x, y] and
    
          
    
    A8: x 
    in A and 
    
          
    
    A9: y 
    in B by 
    RELSET_1: 2;
    
          consider a1,b1 be
    object such that 
    
          
    
    A10: (q 
    `1 ) 
    =  
    [a1, b1] by
    A1,
    Th10;
    
          
    
          
    
    A11: b 
    =  
    [a2, b2] by
    A2,
    A6;
    
          then
    
          
    
    A12: (b 
    `2 ) 
    = t by 
    A3,
    A6,
    XTUPLE_0: 1;
    
          
    
          
    
    A13: a 
    =  
    [a1, b1] by
    A2,
    A10;
    
          then
    
          
    
    A14: (a 
    `2 ) 
    = s by 
    A3,
    A10,
    XTUPLE_0: 1;
    
          (b
    `1 ) 
    = y by 
    A7,
    A6,
    A11,
    XTUPLE_0: 1;
    
          then
    
          
    
    A15: b 
    in  
    [:B, Y:] by
    A9,
    A5,
    A11,
    A12,
    ZFMISC_1:def 2;
    
          (a
    `1 ) 
    = x by 
    A7,
    A10,
    A13,
    XTUPLE_0: 1;
    
          then a
    in  
    [:A, X:] by
    A8,
    A4,
    A13,
    A14,
    ZFMISC_1:def 2;
    
          hence thesis by
    A2,
    A15,
    ZFMISC_1:def 2;
    
        end;
    
        hence thesis;
    
      end;
    
    end
    
    definition
    
      let X,Y be
    RelStr;
    
      :: 
    
    YELLOW_3:def2
    
      func
    
    [:X,Y:] ->
    strict  
    RelStr means 
    
      :
    
    Def2: the 
    carrier of it 
    =  
    [:the 
    carrier of X, the 
    carrier of Y:] & the 
    InternalRel of it 
    =  
    ["the 
    InternalRel of X, the 
    InternalRel of Y"]; 
    
      existence
    
      proof
    
        take
    RelStr (# 
    [:the 
    carrier of X, the 
    carrier of Y:], 
    ["the 
    InternalRel of X, the 
    InternalRel of Y"] #); 
    
        thus thesis;
    
      end;
    
      uniqueness ;
    
    end
    
    definition
    
      let L1,L2 be
    RelStr, D be 
    Subset of 
    [:L1, L2:];
    
      :: original:
    proj1
    
      redefine
    
      func
    
    proj1 D -> 
    Subset of L1 ; 
    
      coherence
    
      proof
    
        (
    proj1 D) 
    c= the 
    carrier of L1 
    
        proof
    
          let x be
    object;
    
          assume x
    in ( 
    proj1 D); 
    
          then
    
          
    
    A1: ex y be 
    object st 
    [x, y]
    in D by 
    XTUPLE_0:def 12;
    
          the
    carrier of 
    [:L1, L2:]
    =  
    [:the 
    carrier of L1, the 
    carrier of L2:] by 
    Def2;
    
          hence thesis by
    A1,
    ZFMISC_1: 87;
    
        end;
    
        hence thesis;
    
      end;
    
      :: original:
    proj2
    
      redefine
    
      func
    
    proj2 D -> 
    Subset of L2 ; 
    
      coherence
    
      proof
    
        (
    proj2 D) 
    c= the 
    carrier of L2 
    
        proof
    
          let y be
    object;
    
          assume y
    in ( 
    proj2 D); 
    
          then
    
          
    
    A2: ex x be 
    object st 
    [x, y]
    in D by 
    XTUPLE_0:def 13;
    
          the
    carrier of 
    [:L1, L2:]
    =  
    [:the 
    carrier of L1, the 
    carrier of L2:] by 
    Def2;
    
          hence thesis by
    A2,
    ZFMISC_1: 87;
    
        end;
    
        hence thesis;
    
      end;
    
    end
    
    definition
    
      let S1,S2 be
    RelStr, D1 be 
    Subset of S1, D2 be 
    Subset of S2; 
    
      :: original:
    [:
    
      redefine
    
      func
    
    [:D1,D2:] ->
    Subset of 
    [:S1, S2:] ;
    
      coherence
    
      proof
    
        
    [:D1, D2:]
    c=  
    [:the 
    carrier of S1, the 
    carrier of S2:]; 
    
        hence thesis by
    Def2;
    
      end;
    
    end
    
    definition
    
      let S1,S2 be non
    empty  
    RelStr, x be 
    Element of S1, y be 
    Element of S2; 
    
      :: original:
    [
    
      redefine
    
      func
    
    [x,y] ->
    Element of 
    [:S1, S2:] ;
    
      coherence
    
      proof
    
        reconsider y1 = y as
    Element of S2; 
    
        reconsider x1 = x as
    Element of S1; 
    
        
    [x1, y1] is
    Element of 
    [:S1, S2:] by
    Def2;
    
        hence thesis;
    
      end;
    
    end
    
    definition
    
      let L1,L2 be non
    empty  
    RelStr, x be 
    Element of 
    [:L1, L2:];
    
      :: original:
    `1
    
      redefine
    
      func x
    
    `1 -> 
    Element of L1 ; 
    
      coherence
    
      proof
    
        the
    carrier of 
    [:L1, L2:]
    =  
    [:the 
    carrier of L1, the 
    carrier of L2:] by 
    Def2;
    
        hence thesis by
    MCART_1: 10;
    
      end;
    
      :: original:
    `2
    
      redefine
    
      func x
    
    `2 -> 
    Element of L2 ; 
    
      coherence
    
      proof
    
        the
    carrier of 
    [:L1, L2:]
    =  
    [:the 
    carrier of L1, the 
    carrier of L2:] by 
    Def2;
    
        hence thesis by
    MCART_1: 10;
    
      end;
    
    end
    
    theorem :: 
    
    YELLOW_3:11
    
    
    
    
    
    Th11: for S1,S2 be non 
    empty  
    RelStr holds for a,c be 
    Element of S1, b,d be 
    Element of S2 holds a 
    <= c & b 
    <= d iff 
    [a, b]
    <=  
    [c, d]
    
    proof
    
      let S1,S2 be non
    empty  
    RelStr, a,c be 
    Element of S1, b,d be 
    Element of S2; 
    
      set I1 = the
    InternalRel of S1, I2 = the 
    InternalRel of S2, x = 
    [
    [a, b],
    [c, d]];
    
      
    
      
    
    A1: ((x 
    `1 ) 
    `1 ) 
    = a & ((x 
    `2 ) 
    `1 ) 
    = c; 
    
      
    
      
    
    A2: ((x 
    `1 ) 
    `2 ) 
    = b & ((x 
    `2 ) 
    `2 ) 
    = d; 
    
      thus a
    <= c & b 
    <= d implies 
    [a, b]
    <=  
    [c, d]
    
      proof
    
        assume a
    <= c & b 
    <= d; 
    
        then
    [((x
    `1 ) 
    `1 ), ((x 
    `2 ) 
    `1 )] 
    in I1 & 
    [((x
    `1 ) 
    `2 ), ((x 
    `2 ) 
    `2 )] 
    in I2; 
    
        then x
    in  
    ["I1, I2"] by
    Th10;
    
        hence
    [
    [a, b],
    [c, d]]
    in the 
    InternalRel of 
    [:S1, S2:] by
    Def2;
    
      end;
    
      assume
    [a, b]
    <=  
    [c, d];
    
      then x
    in the 
    InternalRel of 
    [:S1, S2:];
    
      then x
    in  
    ["I1, I2"] by
    Def2;
    
      hence
    [a, c]
    in the 
    InternalRel of S1 & 
    [b, d]
    in the 
    InternalRel of S2 by 
    A1,
    A2,
    Th10;
    
    end;
    
    theorem :: 
    
    YELLOW_3:12
    
    
    
    
    
    Th12: for S1,S2 be non 
    empty  
    RelStr, x,y be 
    Element of 
    [:S1, S2:] holds x
    <= y iff (x 
    `1 ) 
    <= (y 
    `1 ) & (x 
    `2 ) 
    <= (y 
    `2 ) 
    
    proof
    
      let S1,S2 be non
    empty  
    RelStr, x,y be 
    Element of 
    [:S1, S2:];
    
      
    
      
    
    A1: the 
    carrier of 
    [:S1, S2:]
    =  
    [:the 
    carrier of S1, the 
    carrier of S2:] by 
    Def2;
    
      then ex c,d be
    object st c 
    in the 
    carrier of S1 & d 
    in the 
    carrier of S2 & y 
    =  
    [c, d] by
    ZFMISC_1:def 2;
    
      then
    
      
    
    A2: y 
    =  
    [(y
    `1 ), (y 
    `2 )]; 
    
      ex a,b be
    object st a 
    in the 
    carrier of S1 & b 
    in the 
    carrier of S2 & x 
    =  
    [a, b] by
    A1,
    ZFMISC_1:def 2;
    
      then x
    =  
    [(x
    `1 ), (x 
    `2 )]; 
    
      hence thesis by
    A2,
    Th11;
    
    end;
    
    theorem :: 
    
    YELLOW_3:13
    
    for A,B be
    RelStr, C be non 
    empty  
    RelStr holds for f,g be 
    Function of 
    [:A, B:], C st for x be
    Element of A, y be 
    Element of B holds (f 
    . (x,y)) 
    = (g 
    . (x,y)) holds f 
    = g 
    
    proof
    
      let A,B be
    RelStr, C be non 
    empty  
    RelStr, f,g be 
    Function of 
    [:A, B:], C;
    
      assume for x be
    Element of A, y be 
    Element of B holds (f 
    . (x,y)) 
    = (g 
    . (x,y)); 
    
      then
    
      
    
    A1: for x,y be 
    set st x 
    in the 
    carrier of A & y 
    in the 
    carrier of B holds (f 
    . (x,y)) 
    = (g 
    . (x,y)); 
    
      the
    carrier of 
    [:A, B:]
    =  
    [:the 
    carrier of A, the 
    carrier of B:] by 
    Def2;
    
      hence thesis by
    A1,
    BINOP_1: 1;
    
    end;
    
    registration
    
      let X,Y be non
    empty  
    RelStr;
    
      cluster 
    [:X, Y:] -> non
    empty;
    
      coherence
    
      proof
    
        set y = the
    Element of Y; 
    
        set x = the
    Element of X; 
    
        
    [x, y]
    in  
    [:the 
    carrier of X, the 
    carrier of Y:] by 
    ZFMISC_1: 87;
    
        hence thesis by
    Def2;
    
      end;
    
    end
    
    registration
    
      let X,Y be
    reflexive  
    RelStr;
    
      cluster 
    [:X, Y:] ->
    reflexive;
    
      coherence
    
      proof
    
        let x be
    object;
    
        assume x
    in the 
    carrier of 
    [:X, Y:];
    
        then x
    in  
    [:the 
    carrier of X, the 
    carrier of Y:] by 
    Def2;
    
        then
    
        consider x1,x2 be
    object such that 
    
        
    
    A1: x1 
    in the 
    carrier of X and 
    
        
    
    A2: x2 
    in the 
    carrier of Y and 
    
        
    
    A3: x 
    =  
    [x1, x2] by
    ZFMISC_1:def 2;
    
        the
    InternalRel of X 
    is_reflexive_in the 
    carrier of X by 
    ORDERS_2:def 2;
    
        then
    
        
    
    A4: 
    [x1, x1]
    in the 
    InternalRel of X by 
    A1;
    
        the
    InternalRel of Y 
    is_reflexive_in the 
    carrier of Y by 
    ORDERS_2:def 2;
    
        then
    
        
    
    A5: 
    [x2, x2]
    in the 
    InternalRel of Y by 
    A2;
    
        set a =
    [
    [x1, x2],
    [x1, x2]];
    
        
    
        
    
    A6: (a 
    `1 ) 
    =  
    [x1, x2] & (a
    `2 ) 
    =  
    [x1, x2];
    
        ((a
    `1 ) 
    `1 ) 
    = x1 & ((a 
    `1 ) 
    `2 ) 
    = x2; 
    
        then
    [x, x]
    in  
    ["the 
    InternalRel of X, the 
    InternalRel of Y"] by 
    A3,
    A4,
    A5,
    A6,
    Th10;
    
        hence thesis by
    Def2;
    
      end;
    
    end
    
    registration
    
      let X,Y be
    antisymmetric  
    RelStr;
    
      cluster 
    [:X, Y:] ->
    antisymmetric;
    
      coherence
    
      proof
    
        let x,y be
    object such that 
    
        
    
    A1: x 
    in the 
    carrier of 
    [:X, Y:] and
    
        
    
    A2: y 
    in the 
    carrier of 
    [:X, Y:] and
    
        
    
    A3: 
    [x, y]
    in the 
    InternalRel of 
    [:X, Y:] and
    
        
    
    A4: 
    [y, x]
    in the 
    InternalRel of 
    [:X, Y:];
    
        x
    in  
    [:the 
    carrier of X, the 
    carrier of Y:] by 
    A1,
    Def2;
    
        then
    
        consider x1,x2 be
    object such that 
    
        
    
    A5: x1 
    in the 
    carrier of X and 
    
        
    
    A6: x2 
    in the 
    carrier of Y and 
    
        
    
    A7: x 
    =  
    [x1, x2] by
    ZFMISC_1:def 2;
    
        y
    in  
    [:the 
    carrier of X, the 
    carrier of Y:] by 
    A2,
    Def2;
    
        then
    
        consider y1,y2 be
    object such that 
    
        
    
    A8: y1 
    in the 
    carrier of X and 
    
        
    
    A9: y2 
    in the 
    carrier of Y and 
    
        
    
    A10: y 
    =  
    [y1, y2] by
    ZFMISC_1:def 2;
    
        
    
        
    
    A11: 
    [y, x]
    in  
    ["the 
    InternalRel of X, the 
    InternalRel of Y"] by 
    A4,
    Def2;
    
        then
    [((
    [y, x]
    `1 ) 
    `1 ), (( 
    [y, x]
    `2 ) 
    `1 )] 
    in the 
    InternalRel of X by 
    Th10;
    
        then
    [(y
    `1 ), (( 
    [y, x]
    `2 ) 
    `1 )] 
    in the 
    InternalRel of X; 
    
        then
    [(y
    `1 ), (x 
    `1 )] 
    in the 
    InternalRel of X; 
    
        then
    [y1, (
    [x1, x2]
    `1 )] 
    in the 
    InternalRel of X by 
    A7,
    A10;
    
        then
    
        
    
    A12: 
    [y1, x1]
    in the 
    InternalRel of X; 
    
        
    [((
    [y, x]
    `1 ) 
    `2 ), (( 
    [y, x]
    `2 ) 
    `2 )] 
    in the 
    InternalRel of Y by 
    A11,
    Th10;
    
        then
    [(y
    `2 ), (( 
    [y, x]
    `2 ) 
    `2 )] 
    in the 
    InternalRel of Y; 
    
        then
    [(y
    `2 ), (x 
    `2 )] 
    in the 
    InternalRel of Y; 
    
        then
    [y2, (
    [x1, x2]
    `2 )] 
    in the 
    InternalRel of Y by 
    A7,
    A10;
    
        then
    
        
    
    A13: 
    [y2, x2]
    in the 
    InternalRel of Y; 
    
        
    
        
    
    A14: 
    [x, y]
    in  
    ["the 
    InternalRel of X, the 
    InternalRel of Y"] by 
    A3,
    Def2;
    
        then
    [((
    [x, y]
    `1 ) 
    `2 ), (( 
    [x, y]
    `2 ) 
    `2 )] 
    in the 
    InternalRel of Y by 
    Th10;
    
        then
    [(x
    `2 ), (( 
    [x, y]
    `2 ) 
    `2 )] 
    in the 
    InternalRel of Y; 
    
        then
    [(x
    `2 ), (y 
    `2 )] 
    in the 
    InternalRel of Y; 
    
        then
    [x2, (
    [y1, y2]
    `2 )] 
    in the 
    InternalRel of Y by 
    A7,
    A10;
    
        then
    
        
    
    A15: 
    [x2, y2]
    in the 
    InternalRel of Y; 
    
        
    [((
    [x, y]
    `1 ) 
    `1 ), (( 
    [x, y]
    `2 ) 
    `1 )] 
    in the 
    InternalRel of X by 
    A14,
    Th10;
    
        then
    [(x
    `1 ), (( 
    [x, y]
    `2 ) 
    `1 )] 
    in the 
    InternalRel of X; 
    
        then
    [(x
    `1 ), (y 
    `1 )] 
    in the 
    InternalRel of X; 
    
        then
    [x1, (
    [y1, y2]
    `1 )] 
    in the 
    InternalRel of X by 
    A7,
    A10;
    
        then
    [x1, y1]
    in the 
    InternalRel of X; 
    
        then the
    InternalRel of Y 
    is_antisymmetric_in the 
    carrier of Y & x1 
    = y1 by 
    A5,
    A8,
    A12,
    ORDERS_2:def 4,
    RELAT_2:def 4;
    
        hence thesis by
    A6,
    A7,
    A9,
    A10,
    A15,
    A13;
    
      end;
    
    end
    
    registration
    
      let X,Y be
    transitive  
    RelStr;
    
      cluster 
    [:X, Y:] ->
    transitive;
    
      coherence
    
      proof
    
        set P = the
    InternalRel of X, R = the 
    InternalRel of Y; 
    
        let x,y,z be
    object such that 
    
        
    
    A1: x 
    in the 
    carrier of 
    [:X, Y:] and
    
        
    
    A2: y 
    in the 
    carrier of 
    [:X, Y:] and
    
        
    
    A3: z 
    in the 
    carrier of 
    [:X, Y:] and
    
        
    
    A4: 
    [x, y]
    in the 
    InternalRel of 
    [:X, Y:] and
    
        
    
    A5: 
    [y, z]
    in the 
    InternalRel of 
    [:X, Y:];
    
        y
    in  
    [:the 
    carrier of X, the 
    carrier of Y:] by 
    A2,
    Def2;
    
        then
    
        consider y1,y2 be
    object such that 
    
        
    
    A6: y1 
    in the 
    carrier of X and 
    
        
    
    A7: y2 
    in the 
    carrier of Y and 
    
        
    
    A8: y 
    =  
    [y1, y2] by
    ZFMISC_1:def 2;
    
        z
    in  
    [:the 
    carrier of X, the 
    carrier of Y:] by 
    A3,
    Def2;
    
        then
    
        consider z1,z2 be
    object such that 
    
        
    
    A9: z1 
    in the 
    carrier of X and 
    
        
    
    A10: z2 
    in the 
    carrier of Y and 
    
        
    
    A11: z 
    =  
    [z1, z2] by
    ZFMISC_1:def 2;
    
        
    
        
    
    A12: 
    [y, z]
    in  
    ["P, R"] by
    A5,
    Def2;
    
        then
    [((
    [y, z]
    `1 ) 
    `1 ), (( 
    [y, z]
    `2 ) 
    `1 )] 
    in P by 
    Th10;
    
        then
    [(y
    `1 ), (( 
    [y, z]
    `2 ) 
    `1 )] 
    in P; 
    
        then
    [(y
    `1 ), (z 
    `1 )] 
    in P; 
    
        then
    [y1, (z
    `1 )] 
    in P by 
    A8;
    
        then
    
        
    
    A13: 
    [y1, z1]
    in P by 
    A11;
    
        x
    in  
    [:the 
    carrier of X, the 
    carrier of Y:] by 
    A1,
    Def2;
    
        then
    
        consider x1,x2 be
    object such that 
    
        
    
    A14: x1 
    in the 
    carrier of X and 
    
        
    
    A15: x2 
    in the 
    carrier of Y and 
    
        
    
    A16: x 
    =  
    [x1, x2] by
    ZFMISC_1:def 2;
    
        
    
        
    
    A17: 
    [x, y]
    in  
    ["P, R"] by
    A4,
    Def2;
    
        then
    [((
    [x, y]
    `1 ) 
    `1 ), (( 
    [x, y]
    `2 ) 
    `1 )] 
    in P by 
    Th10;
    
        then
    [(x
    `1 ), (( 
    [x, y]
    `2 ) 
    `1 )] 
    in P; 
    
        then
    [(x
    `1 ), (y 
    `1 )] 
    in P; 
    
        then
    [x1, (y
    `1 )] 
    in P by 
    A16;
    
        then P
    is_transitive_in the 
    carrier of X & 
    [x1, y1]
    in P by 
    A8,
    ORDERS_2:def 3;
    
        then
    [x1, z1]
    in P by 
    A14,
    A6,
    A9,
    A13;
    
        then
    [x1, (z
    `1 )] 
    in P by 
    A11;
    
        then
    
        
    
    A18: 
    [(x
    `1 ), (z 
    `1 )] 
    in P by 
    A16;
    
        
    [((
    [y, z]
    `1 ) 
    `2 ), (( 
    [y, z]
    `2 ) 
    `2 )] 
    in R by 
    A12,
    Th10;
    
        then
    [(y
    `2 ), (( 
    [y, z]
    `2 ) 
    `2 )] 
    in R; 
    
        then
    [(y
    `2 ), (z 
    `2 )] 
    in R; 
    
        then
    [y2, (z
    `2 )] 
    in R by 
    A8;
    
        then
    
        
    
    A19: 
    [y2, z2]
    in R by 
    A11;
    
        
    [((
    [x, y]
    `1 ) 
    `2 ), (( 
    [x, y]
    `2 ) 
    `2 )] 
    in R by 
    A17,
    Th10;
    
        then
    [(x
    `2 ), (( 
    [x, y]
    `2 ) 
    `2 )] 
    in R; 
    
        then
    [(x
    `2 ), (y 
    `2 )] 
    in R; 
    
        then
    [x2, (y
    `2 )] 
    in R by 
    A16;
    
        then R
    is_transitive_in the 
    carrier of Y & 
    [x2, y2]
    in R by 
    A8,
    ORDERS_2:def 3;
    
        then
    [x2, z2]
    in R by 
    A15,
    A7,
    A10,
    A19;
    
        then
    [x2, (z
    `2 )] 
    in R by 
    A11;
    
        then
    
        
    
    A20: 
    [(x
    `2 ), (z 
    `2 )] 
    in R by 
    A16;
    
        (
    [x, z]
    `1 ) 
    = x & ( 
    [x, z]
    `2 ) 
    = z; 
    
        then
    [x, z]
    in  
    ["P, R"] by
    A16,
    A11,
    A18,
    A20,
    Th10;
    
        hence thesis by
    Def2;
    
      end;
    
    end
    
    registration
    
      let X,Y be
    with_suprema  
    RelStr;
    
      cluster 
    [:X, Y:] ->
    with_suprema;
    
      coherence
    
      proof
    
        set IT =
    [:X, Y:];
    
        let x,y be
    Element of IT; 
    
        consider zx be
    Element of X such that 
    
        
    
    A1: (x 
    `1 ) 
    <= zx & (y 
    `1 ) 
    <= zx and 
    
        
    
    A2: for z9 be 
    Element of X st (x 
    `1 ) 
    <= z9 & (y 
    `1 ) 
    <= z9 holds zx 
    <= z9 by 
    LATTICE3:def 10;
    
        consider zy be
    Element of Y such that 
    
        
    
    A3: (x 
    `2 ) 
    <= zy & (y 
    `2 ) 
    <= zy and 
    
        
    
    A4: for z9 be 
    Element of Y st (x 
    `2 ) 
    <= z9 & (y 
    `2 ) 
    <= z9 holds zy 
    <= z9 by 
    LATTICE3:def 10;
    
        
    
        
    
    A5: the 
    carrier of 
    [:X, Y:]
    =  
    [:the 
    carrier of X, the 
    carrier of Y:] by 
    Def2;
    
        then
    
        
    
    A6: (ex a,b be 
    object st a 
    in the 
    carrier of X & b 
    in the 
    carrier of Y & x 
    =  
    [a, b]) & ex c,d be
    object st c 
    in the 
    carrier of X & d 
    in the 
    carrier of Y & y 
    =  
    [c, d] by
    ZFMISC_1:def 2;
    
        take z =
    [zx, zy];
    
        
    [(x
    `1 ), (x 
    `2 )] 
    <=  
    [zx, zy] &
    [(y
    `1 ), (y 
    `2 )] 
    <=  
    [zx, zy] by
    A1,
    A3,
    Th11;
    
        hence x
    <= z & y 
    <= z by 
    A6;
    
        let z9 be
    Element of IT; 
    
        
    
        
    
    A7: ex a,b be 
    object st a 
    in the 
    carrier of X & b 
    in the 
    carrier of Y & z9 
    =  
    [a, b] by
    A5,
    ZFMISC_1:def 2;
    
        assume
    
        
    
    A8: x 
    <= z9 & y 
    <= z9; 
    
        then (x
    `2 ) 
    <= (z9 
    `2 ) & (y 
    `2 ) 
    <= (z9 
    `2 ) by 
    Th12;
    
        then
    
        
    
    A9: zy 
    <= (z9 
    `2 ) by 
    A4;
    
        (x
    `1 ) 
    <= (z9 
    `1 ) & (y 
    `1 ) 
    <= (z9 
    `1 ) by 
    A8,
    Th12;
    
        then zx
    <= (z9 
    `1 ) by 
    A2;
    
        then
    [zx, zy]
    <=  
    [(z9
    `1 ), (z9 
    `2 )] by 
    A9,
    Th11;
    
        hence thesis by
    A7;
    
      end;
    
    end
    
    registration
    
      let X,Y be
    with_infima  
    RelStr;
    
      cluster 
    [:X, Y:] ->
    with_infima;
    
      coherence
    
      proof
    
        set IT =
    [:X, Y:];
    
        let x,y be
    Element of IT; 
    
        consider zx be
    Element of X such that 
    
        
    
    A1: (x 
    `1 ) 
    >= zx & (y 
    `1 ) 
    >= zx and 
    
        
    
    A2: for z9 be 
    Element of X st (x 
    `1 ) 
    >= z9 & (y 
    `1 ) 
    >= z9 holds zx 
    >= z9 by 
    LATTICE3:def 11;
    
        consider zy be
    Element of Y such that 
    
        
    
    A3: (x 
    `2 ) 
    >= zy & (y 
    `2 ) 
    >= zy and 
    
        
    
    A4: for z9 be 
    Element of Y st (x 
    `2 ) 
    >= z9 & (y 
    `2 ) 
    >= z9 holds zy 
    >= z9 by 
    LATTICE3:def 11;
    
        
    
        
    
    A5: the 
    carrier of 
    [:X, Y:]
    =  
    [:the 
    carrier of X, the 
    carrier of Y:] by 
    Def2;
    
        then
    
        
    
    A6: (ex a,b be 
    object st a 
    in the 
    carrier of X & b 
    in the 
    carrier of Y & x 
    =  
    [a, b]) & ex c,d be
    object st c 
    in the 
    carrier of X & d 
    in the 
    carrier of Y & y 
    =  
    [c, d] by
    ZFMISC_1:def 2;
    
        take z =
    [zx, zy];
    
        
    [(x
    `1 ), (x 
    `2 )] 
    >=  
    [zx, zy] &
    [(y
    `1 ), (y 
    `2 )] 
    >=  
    [zx, zy] by
    A1,
    A3,
    Th11;
    
        hence x
    >= z & y 
    >= z by 
    A6;
    
        let z9 be
    Element of IT; 
    
        
    
        
    
    A7: ex a,b be 
    object st a 
    in the 
    carrier of X & b 
    in the 
    carrier of Y & z9 
    =  
    [a, b] by
    A5,
    ZFMISC_1:def 2;
    
        assume
    
        
    
    A8: x 
    >= z9 & y 
    >= z9; 
    
        then (x
    `2 ) 
    >= (z9 
    `2 ) & (y 
    `2 ) 
    >= (z9 
    `2 ) by 
    Th12;
    
        then
    
        
    
    A9: zy 
    >= (z9 
    `2 ) by 
    A4;
    
        (x
    `1 ) 
    >= (z9 
    `1 ) & (y 
    `1 ) 
    >= (z9 
    `1 ) by 
    A8,
    Th12;
    
        then zx
    >= (z9 
    `1 ) by 
    A2;
    
        then
    [zx, zy]
    >=  
    [(z9
    `1 ), (z9 
    `2 )] by 
    A9,
    Th11;
    
        hence thesis by
    A7;
    
      end;
    
    end
    
    theorem :: 
    
    YELLOW_3:14
    
    for X,Y be
    RelStr st 
    [:X, Y:] is non
    empty holds X is non 
    empty & Y is non 
    empty
    
    proof
    
      let X,Y be
    RelStr;
    
      assume
    [:X, Y:] is non
    empty;
    
      then
    
      
    
    A1: ex x be 
    object st x 
    in the 
    carrier of 
    [:X, Y:] by
    XBOOLE_0:def 1;
    
      the
    carrier of 
    [:X, Y:]
    =  
    [:the 
    carrier of X, the 
    carrier of Y:] by 
    Def2;
    
      hence thesis by
    A1,
    MCART_1: 10;
    
    end;
    
    theorem :: 
    
    YELLOW_3:15
    
    for X,Y be non
    empty  
    RelStr st 
    [:X, Y:] is
    reflexive holds X is 
    reflexive & Y is 
    reflexive
    
    proof
    
      let X,Y be non
    empty  
    RelStr such that 
    
      
    
    A1: 
    [:X, Y:] is
    reflexive;
    
      for x be
    Element of X holds x 
    <= x 
    
      proof
    
        set y = the
    Element of Y; 
    
        let x be
    Element of X; 
    
        
    [x, y]
    <=  
    [x, y] by
    A1,
    YELLOW_0:def 1;
    
        hence thesis by
    Th11;
    
      end;
    
      hence X is
    reflexive by 
    YELLOW_0:def 1;
    
      for y be
    Element of Y holds y 
    <= y 
    
      proof
    
        set x = the
    Element of X; 
    
        let y be
    Element of Y; 
    
        
    [x, y]
    <=  
    [x, y] by
    A1,
    YELLOW_0:def 1;
    
        hence thesis by
    Th11;
    
      end;
    
      hence thesis by
    YELLOW_0:def 1;
    
    end;
    
    theorem :: 
    
    YELLOW_3:16
    
    for X,Y be non
    empty
    reflexive  
    RelStr st 
    [:X, Y:] is
    antisymmetric holds X is 
    antisymmetric & Y is 
    antisymmetric
    
    proof
    
      let X,Y be non
    empty
    reflexive  
    RelStr such that 
    
      
    
    A1: 
    [:X, Y:] is
    antisymmetric;
    
      for x,y be
    Element of X st x 
    <= y & y 
    <= x holds x 
    = y 
    
      proof
    
        set z = the
    Element of Y; 
    
        
    
        
    
    A2: z 
    <= z; 
    
        let x,y be
    Element of X; 
    
        assume x
    <= y & y 
    <= x; 
    
        then
    [x, z]
    <=  
    [y, z] &
    [y, z]
    <=  
    [x, z] by
    A2,
    Th11;
    
        then
    [x, z]
    =  
    [y, z] by
    A1,
    YELLOW_0:def 3;
    
        hence thesis by
    XTUPLE_0: 1;
    
      end;
    
      hence X is
    antisymmetric by 
    YELLOW_0:def 3;
    
      for x,y be
    Element of Y st x 
    <= y & y 
    <= x holds x 
    = y 
    
      proof
    
        set z = the
    Element of X; 
    
        
    
        
    
    A3: z 
    <= z; 
    
        let x,y be
    Element of Y; 
    
        assume x
    <= y & y 
    <= x; 
    
        then
    [z, x]
    <=  
    [z, y] &
    [z, y]
    <=  
    [z, x] by
    A3,
    Th11;
    
        then
    [z, x]
    =  
    [z, y] by
    A1,
    YELLOW_0:def 3;
    
        hence thesis by
    XTUPLE_0: 1;
    
      end;
    
      hence thesis by
    YELLOW_0:def 3;
    
    end;
    
    theorem :: 
    
    YELLOW_3:17
    
    for X,Y be non
    empty
    reflexive  
    RelStr st 
    [:X, Y:] is
    transitive holds X is 
    transitive & Y is 
    transitive
    
    proof
    
      let X,Y be non
    empty
    reflexive  
    RelStr such that 
    
      
    
    A1: 
    [:X, Y:] is
    transitive;
    
      for x,y,z be
    Element of X st x 
    <= y & y 
    <= z holds x 
    <= z 
    
      proof
    
        set a = the
    Element of Y; 
    
        
    
        
    
    A2: a 
    <= a; 
    
        let x,y,z be
    Element of X; 
    
        assume x
    <= y & y 
    <= z; 
    
        then
    [x, a]
    <=  
    [y, a] &
    [y, a]
    <=  
    [z, a] by
    A2,
    Th11;
    
        then
    [x, a]
    <=  
    [z, a] by
    A1,
    YELLOW_0:def 2;
    
        hence thesis by
    Th11;
    
      end;
    
      hence X is
    transitive by 
    YELLOW_0:def 2;
    
      for x,y,z be
    Element of Y st x 
    <= y & y 
    <= z holds x 
    <= z 
    
      proof
    
        set a = the
    Element of X; 
    
        
    
        
    
    A3: a 
    <= a; 
    
        let x,y,z be
    Element of Y; 
    
        assume x
    <= y & y 
    <= z; 
    
        then
    [a, x]
    <=  
    [a, y] &
    [a, y]
    <=  
    [a, z] by
    A3,
    Th11;
    
        then
    [a, x]
    <=  
    [a, z] by
    A1,
    YELLOW_0:def 2;
    
        hence thesis by
    Th11;
    
      end;
    
      hence thesis by
    YELLOW_0:def 2;
    
    end;
    
    theorem :: 
    
    YELLOW_3:18
    
    for X,Y be non
    empty
    reflexive  
    RelStr st 
    [:X, Y:] is
    with_suprema holds X is 
    with_suprema & Y is 
    with_suprema
    
    proof
    
      let X,Y be non
    empty
    reflexive  
    RelStr such that 
    
      
    
    A1: 
    [:X, Y:] is
    with_suprema;
    
      
    
      
    
    A2: the 
    carrier of 
    [:X, Y:]
    =  
    [:the 
    carrier of X, the 
    carrier of Y:] by 
    Def2;
    
      thus X is
    with_suprema
    
      proof
    
        let x,y be
    Element of X; 
    
        set a = the
    Element of Y; 
    
        
    
        
    
    A3: a 
    <= a; 
    
        consider z be
    Element of 
    [:X, Y:] such that
    
        
    
    A4: 
    [x, a]
    <= z & 
    [y, a]
    <= z and 
    
        
    
    A5: for z9 be 
    Element of 
    [:X, Y:] st
    [x, a]
    <= z9 & 
    [y, a]
    <= z9 holds z 
    <= z9 by 
    A1;
    
        take (z
    `1 ); 
    
        
    
        
    
    A6: z 
    =  
    [(z
    `1 ), (z 
    `2 )] by 
    A2,
    MCART_1: 21;
    
        hence x
    <= (z 
    `1 ) & y 
    <= (z 
    `1 ) by 
    A4,
    Th11;
    
        let z9 be
    Element of X; 
    
        assume x
    <= z9 & y 
    <= z9; 
    
        then
    [x, a]
    <=  
    [z9, a] &
    [y, a]
    <=  
    [z9, a] by
    A3,
    Th11;
    
        then z
    <=  
    [z9, a] by
    A5;
    
        hence (z
    `1 ) 
    <= z9 by 
    A6,
    Th11;
    
      end;
    
      set a = the
    Element of X; 
    
      
    
      
    
    A7: a 
    <= a; 
    
      let x,y be
    Element of Y; 
    
      consider z be
    Element of 
    [:X, Y:] such that
    
      
    
    A8: 
    [a, x]
    <= z & 
    [a, y]
    <= z and 
    
      
    
    A9: for z9 be 
    Element of 
    [:X, Y:] st
    [a, x]
    <= z9 & 
    [a, y]
    <= z9 holds z 
    <= z9 by 
    A1;
    
      take (z
    `2 ); 
    
      
    
      
    
    A10: z 
    =  
    [(z
    `1 ), (z 
    `2 )] by 
    A2,
    MCART_1: 21;
    
      hence x
    <= (z 
    `2 ) & y 
    <= (z 
    `2 ) by 
    A8,
    Th11;
    
      let z9 be
    Element of Y; 
    
      assume x
    <= z9 & y 
    <= z9; 
    
      then
    [a, x]
    <=  
    [a, z9] &
    [a, y]
    <=  
    [a, z9] by
    A7,
    Th11;
    
      then z
    <=  
    [a, z9] by
    A9;
    
      hence (z
    `2 ) 
    <= z9 by 
    A10,
    Th11;
    
    end;
    
    theorem :: 
    
    YELLOW_3:19
    
    for X,Y be non
    empty
    reflexive  
    RelStr st 
    [:X, Y:] is
    with_infima holds X is 
    with_infima & Y is 
    with_infima
    
    proof
    
      let X,Y be non
    empty
    reflexive  
    RelStr such that 
    
      
    
    A1: 
    [:X, Y:] is
    with_infima;
    
      
    
      
    
    A2: the 
    carrier of 
    [:X, Y:]
    =  
    [:the 
    carrier of X, the 
    carrier of Y:] by 
    Def2;
    
      thus X is
    with_infima
    
      proof
    
        let x,y be
    Element of X; 
    
        set a = the
    Element of Y; 
    
        
    
        
    
    A3: a 
    <= a; 
    
        consider z be
    Element of 
    [:X, Y:] such that
    
        
    
    A4: 
    [x, a]
    >= z & 
    [y, a]
    >= z and 
    
        
    
    A5: for z9 be 
    Element of 
    [:X, Y:] st
    [x, a]
    >= z9 & 
    [y, a]
    >= z9 holds z 
    >= z9 by 
    A1;
    
        take (z
    `1 ); 
    
        
    
        
    
    A6: z 
    =  
    [(z
    `1 ), (z 
    `2 )] by 
    A2,
    MCART_1: 21;
    
        hence x
    >= (z 
    `1 ) & y 
    >= (z 
    `1 ) by 
    A4,
    Th11;
    
        let z9 be
    Element of X; 
    
        assume x
    >= z9 & y 
    >= z9; 
    
        then
    [x, a]
    >=  
    [z9, a] &
    [y, a]
    >=  
    [z9, a] by
    A3,
    Th11;
    
        then z
    >=  
    [z9, a] by
    A5;
    
        hence thesis by
    A6,
    Th11;
    
      end;
    
      set a = the
    Element of X; 
    
      
    
      
    
    A7: a 
    <= a; 
    
      let x,y be
    Element of Y; 
    
      consider z be
    Element of 
    [:X, Y:] such that
    
      
    
    A8: 
    [a, x]
    >= z & 
    [a, y]
    >= z and 
    
      
    
    A9: for z9 be 
    Element of 
    [:X, Y:] st
    [a, x]
    >= z9 & 
    [a, y]
    >= z9 holds z 
    >= z9 by 
    A1;
    
      take (z
    `2 ); 
    
      
    
      
    
    A10: z 
    =  
    [(z
    `1 ), (z 
    `2 )] by 
    A2,
    MCART_1: 21;
    
      hence x
    >= (z 
    `2 ) & y 
    >= (z 
    `2 ) by 
    A8,
    Th11;
    
      let z9 be
    Element of Y; 
    
      assume x
    >= z9 & y 
    >= z9; 
    
      then
    [a, x]
    >=  
    [a, z9] &
    [a, y]
    >=  
    [a, z9] by
    A7,
    Th11;
    
      then z
    >=  
    [a, z9] by
    A9;
    
      hence thesis by
    A10,
    Th11;
    
    end;
    
    registration
    
      let S1,S2 be
    RelStr;
    
      let D1 be
    directed  
    Subset of S1, D2 be 
    directed  
    Subset of S2; 
    
      cluster 
    [:D1, D2:] ->
    directed;
    
      coherence
    
      proof
    
        set X =
    [:D1, D2:];
    
        X is
    directed
    
        proof
    
          let x,y be
    Element of 
    [:S1, S2:];
    
          assume that
    
          
    
    A1: x 
    in X and 
    
          
    
    A2: y 
    in X; 
    
          consider x1,x2 be
    object such that 
    
          
    
    A3: x1 
    in D1 and 
    
          
    
    A4: x2 
    in D2 and 
    
          
    
    A5: x 
    =  
    [x1, x2] by
    A1,
    ZFMISC_1:def 2;
    
          reconsider S29 = S2 as non
    empty  
    RelStr by 
    A4;
    
          reconsider S19 = S1 as non
    empty  
    RelStr by 
    A3;
    
          consider y1,y2 be
    object such that 
    
          
    
    A6: y1 
    in D1 and 
    
          
    
    A7: y2 
    in D2 and 
    
          
    
    A8: y 
    =  
    [y1, y2] by
    A2,
    ZFMISC_1:def 2;
    
          reconsider x2, y2 as
    Element of S2 by 
    A4,
    A7;
    
          consider xy2 be
    Element of S2 such that 
    
          
    
    A9: xy2 
    in D2 and 
    
          
    
    A10: x2 
    <= xy2 & y2 
    <= xy2 by 
    A4,
    A7,
    WAYBEL_0:def 1;
    
          reconsider x1, y1 as
    Element of S1 by 
    A3,
    A6;
    
          consider xy1 be
    Element of S1 such that 
    
          
    
    A11: xy1 
    in D1 and 
    
          
    
    A12: x1 
    <= xy1 & y1 
    <= xy1 by 
    A3,
    A6,
    WAYBEL_0:def 1;
    
          reconsider xy29 = xy2 as
    Element of S29; 
    
          reconsider xy19 = xy1 as
    Element of S19; 
    
          
    [xy19, xy29] is
    Element of 
    [:S19, S29:];
    
          then
    
          reconsider z =
    [xy1, xy2] as
    Element of 
    [:S1, S2:];
    
          take z;
    
          thus z
    in X by 
    A11,
    A9,
    ZFMISC_1: 87;
    
          S1 is non
    empty & S2 is non 
    empty by 
    A3,
    A4;
    
          hence thesis by
    A5,
    A8,
    A12,
    A10,
    Th11;
    
        end;
    
        hence thesis;
    
      end;
    
    end
    
    theorem :: 
    
    YELLOW_3:20
    
    for S1,S2 be non
    empty  
    RelStr holds for D1 be non 
    empty  
    Subset of S1, D2 be non 
    empty  
    Subset of S2 st 
    [:D1, D2:] is
    directed holds D1 is 
    directed & D2 is 
    directed
    
    proof
    
      let S1,S2 be non
    empty  
    RelStr, D1 be non 
    empty  
    Subset of S1, D2 be non 
    empty  
    Subset of S2 such that 
    
      
    
    A1: 
    [:D1, D2:] is
    directed;
    
      thus D1 is
    directed
    
      proof
    
        set q1 = the
    Element of D2; 
    
        let x,y be
    Element of S1; 
    
        assume x
    in D1 & y 
    in D1; 
    
        then
    [x, q1]
    in  
    [:D1, D2:] &
    [y, q1]
    in  
    [:D1, D2:] by
    ZFMISC_1: 87;
    
        then
    
        consider z be
    Element of 
    [:S1, S2:] such that
    
        
    
    A2: z 
    in  
    [:D1, D2:] and
    
        
    
    A3: 
    [x, q1]
    <= z & 
    [y, q1]
    <= z by 
    A1;
    
        reconsider z2 = (z
    `2 ) as 
    Element of D2 by 
    A2,
    MCART_1: 10;
    
        reconsider zz = (z
    `1 ) as 
    Element of D1 by 
    A2,
    MCART_1: 10;
    
        take zz;
    
        thus zz
    in D1; 
    
        ex x,y be
    object st x 
    in D1 & y 
    in D2 & z 
    =  
    [x, y] by
    A2,
    ZFMISC_1:def 2;
    
        then
    [x, q1]
    <=  
    [zz, z2] &
    [y, q1]
    <=  
    [zz, z2] by
    A3;
    
        hence thesis by
    Th11;
    
      end;
    
      set q1 = the
    Element of D1; 
    
      let x,y be
    Element of S2; 
    
      assume x
    in D2 & y 
    in D2; 
    
      then
    [q1, x]
    in  
    [:D1, D2:] &
    [q1, y]
    in  
    [:D1, D2:] by
    ZFMISC_1: 87;
    
      then
    
      consider z be
    Element of 
    [:S1, S2:] such that
    
      
    
    A4: z 
    in  
    [:D1, D2:] and
    
      
    
    A5: 
    [q1, x]
    <= z & 
    [q1, y]
    <= z by 
    A1;
    
      reconsider z2 = (z
    `1 ) as 
    Element of D1 by 
    A4,
    MCART_1: 10;
    
      reconsider zz = (z
    `2 ) as 
    Element of D2 by 
    A4,
    MCART_1: 10;
    
      take zz;
    
      thus zz
    in D2; 
    
      ex x,y be
    object st x 
    in D1 & y 
    in D2 & z 
    =  
    [x, y] by
    A4,
    ZFMISC_1:def 2;
    
      then
    [q1, x]
    <=  
    [z2, zz] &
    [q1, y]
    <=  
    [z2, zz] by
    A5;
    
      hence thesis by
    Th11;
    
    end;
    
    theorem :: 
    
    YELLOW_3:21
    
    
    
    
    
    Th21: for S1,S2 be non 
    empty  
    RelStr holds for D be non 
    empty  
    Subset of 
    [:S1, S2:] holds (
    proj1 D) is non 
    empty & ( 
    proj2 D) is non 
    empty
    
    proof
    
      let S1,S2 be non
    empty  
    RelStr, D be non 
    empty  
    Subset of 
    [:S1, S2:];
    
      reconsider D1 = D as non
    empty  
    Subset of 
    [:the 
    carrier of S1, the 
    carrier of S2:] by 
    Def2;
    
      (
    proj1 D1) is non 
    empty;
    
      hence thesis;
    
    end;
    
    theorem :: 
    
    YELLOW_3:22
    
    for S1,S2 be non
    empty
    reflexive  
    RelStr holds for D be non 
    empty
    directed  
    Subset of 
    [:S1, S2:] holds (
    proj1 D) is 
    directed & ( 
    proj2 D) is 
    directed
    
    proof
    
      let S1,S2 be non
    empty
    reflexive  
    RelStr, D be non 
    empty
    directed  
    Subset of 
    [:S1, S2:];
    
      set D1 = (
    proj1 D), D2 = ( 
    proj2 D); 
    
      the
    carrier of 
    [:S1, S2:]
    =  
    [:the 
    carrier of S1, the 
    carrier of S2:] by 
    Def2;
    
      then
    
      
    
    A1: D 
    c=  
    [:(
    proj1 D), ( 
    proj2 D):] by 
    Th1;
    
      thus D1 is
    directed
    
      proof
    
        let x,y be
    Element of S1; 
    
        assume that
    
        
    
    A2: x 
    in D1 and 
    
        
    
    A3: y 
    in D1; 
    
        consider q2 be
    object such that 
    
        
    
    A4: 
    [y, q2]
    in D by 
    A3,
    XTUPLE_0:def 12;
    
        reconsider D29 = D2 as non
    empty  
    Subset of S2 by 
    A2,
    FUNCT_5: 16;
    
        reconsider D19 = D1 as non
    empty  
    Subset of S1 by 
    A2;
    
        consider q1 be
    object such that 
    
        
    
    A5: 
    [x, q1]
    in D by 
    A2,
    XTUPLE_0:def 12;
    
        reconsider q2 as
    Element of D29 by 
    A4,
    XTUPLE_0:def 13;
    
        reconsider q1 as
    Element of D29 by 
    A5,
    XTUPLE_0:def 13;
    
        consider z be
    Element of 
    [:S1, S2:] such that
    
        
    
    A6: z 
    in D and 
    
        
    
    A7: 
    [x, q1]
    <= z & 
    [y, q2]
    <= z by 
    A5,
    A4,
    WAYBEL_0:def 1;
    
        reconsider z2 = (z
    `2 ) as 
    Element of D29 by 
    A1,
    A6,
    MCART_1: 10;
    
        reconsider zz = (z
    `1 ) as 
    Element of D19 by 
    A1,
    A6,
    MCART_1: 10;
    
        take zz;
    
        thus zz
    in D1; 
    
        ex x,y be
    object st x 
    in D19 & y 
    in D29 & z 
    =  
    [x, y] by
    A1,
    A6,
    ZFMISC_1:def 2;
    
        then z
    =  
    [zz, z2];
    
        hence x
    <= zz & y 
    <= zz by 
    A7,
    Th11;
    
      end;
    
      let x,y be
    Element of S2; 
    
      assume that
    
      
    
    A8: x 
    in D2 and 
    
      
    
    A9: y 
    in D2; 
    
      consider q2 be
    object such that 
    
      
    
    A10: 
    [q2, y]
    in D by 
    A9,
    XTUPLE_0:def 13;
    
      reconsider D29 = D2 as non
    empty  
    Subset of S2 by 
    A8;
    
      reconsider D19 = D1 as non
    empty  
    Subset of S1 by 
    A8,
    FUNCT_5: 16;
    
      consider q1 be
    object such that 
    
      
    
    A11: 
    [q1, x]
    in D by 
    A8,
    XTUPLE_0:def 13;
    
      reconsider q2 as
    Element of D19 by 
    A10,
    XTUPLE_0:def 12;
    
      reconsider q1 as
    Element of D19 by 
    A11,
    XTUPLE_0:def 12;
    
      consider z be
    Element of 
    [:S1, S2:] such that
    
      
    
    A12: z 
    in D and 
    
      
    
    A13: 
    [q1, x]
    <= z & 
    [q2, y]
    <= z by 
    A11,
    A10,
    WAYBEL_0:def 1;
    
      reconsider z2 = (z
    `1 ) as 
    Element of D19 by 
    A1,
    A12,
    MCART_1: 10;
    
      reconsider zz = (z
    `2 ) as 
    Element of D29 by 
    A1,
    A12,
    MCART_1: 10;
    
      take zz;
    
      thus zz
    in D2; 
    
      ex x,y be
    object st x 
    in D19 & y 
    in D29 & z 
    =  
    [x, y] by
    A1,
    A12,
    ZFMISC_1:def 2;
    
      then z
    =  
    [z2, zz];
    
      hence x
    <= zz & y 
    <= zz by 
    A13,
    Th11;
    
    end;
    
    registration
    
      let S1,S2 be
    RelStr;
    
      let D1 be
    filtered  
    Subset of S1, D2 be 
    filtered  
    Subset of S2; 
    
      cluster 
    [:D1, D2:] ->
    filtered;
    
      coherence
    
      proof
    
        set X =
    [:D1, D2:];
    
        X is
    filtered
    
        proof
    
          let x,y be
    Element of 
    [:S1, S2:];
    
          assume that
    
          
    
    A1: x 
    in X and 
    
          
    
    A2: y 
    in X; 
    
          consider x1,x2 be
    object such that 
    
          
    
    A3: x1 
    in D1 and 
    
          
    
    A4: x2 
    in D2 and 
    
          
    
    A5: x 
    =  
    [x1, x2] by
    A1,
    ZFMISC_1:def 2;
    
          reconsider S29 = S2 as non
    empty  
    RelStr by 
    A4;
    
          reconsider S19 = S1 as non
    empty  
    RelStr by 
    A3;
    
          consider y1,y2 be
    object such that 
    
          
    
    A6: y1 
    in D1 and 
    
          
    
    A7: y2 
    in D2 and 
    
          
    
    A8: y 
    =  
    [y1, y2] by
    A2,
    ZFMISC_1:def 2;
    
          reconsider x2, y2 as
    Element of S2 by 
    A4,
    A7;
    
          consider xy2 be
    Element of S2 such that 
    
          
    
    A9: xy2 
    in D2 and 
    
          
    
    A10: x2 
    >= xy2 & y2 
    >= xy2 by 
    A4,
    A7,
    WAYBEL_0:def 2;
    
          reconsider x1, y1 as
    Element of S1 by 
    A3,
    A6;
    
          consider xy1 be
    Element of S1 such that 
    
          
    
    A11: xy1 
    in D1 and 
    
          
    
    A12: x1 
    >= xy1 & y1 
    >= xy1 by 
    A3,
    A6,
    WAYBEL_0:def 2;
    
          reconsider xy29 = xy2 as
    Element of S29; 
    
          reconsider xy19 = xy1 as
    Element of S19; 
    
          
    [xy19, xy29] is
    Element of 
    [:S19, S29:];
    
          then
    
          reconsider z =
    [xy1, xy2] as
    Element of 
    [:S1, S2:];
    
          take z;
    
          thus z
    in X by 
    A11,
    A9,
    ZFMISC_1: 87;
    
          S1 is non
    empty & S2 is non 
    empty by 
    A3,
    A4;
    
          hence thesis by
    A5,
    A8,
    A12,
    A10,
    Th11;
    
        end;
    
        hence thesis;
    
      end;
    
    end
    
    theorem :: 
    
    YELLOW_3:23
    
    for S1,S2 be non
    empty  
    RelStr holds for D1 be non 
    empty  
    Subset of S1, D2 be non 
    empty  
    Subset of S2 st 
    [:D1, D2:] is
    filtered holds D1 is 
    filtered & D2 is 
    filtered
    
    proof
    
      let S1,S2 be non
    empty  
    RelStr, D1 be non 
    empty  
    Subset of S1, D2 be non 
    empty  
    Subset of S2 such that 
    
      
    
    A1: 
    [:D1, D2:] is
    filtered;
    
      thus D1 is
    filtered
    
      proof
    
        set q1 = the
    Element of D2; 
    
        let x,y be
    Element of S1; 
    
        assume x
    in D1 & y 
    in D1; 
    
        then
    [x, q1]
    in  
    [:D1, D2:] &
    [y, q1]
    in  
    [:D1, D2:] by
    ZFMISC_1: 87;
    
        then
    
        consider z be
    Element of 
    [:S1, S2:] such that
    
        
    
    A2: z 
    in  
    [:D1, D2:] and
    
        
    
    A3: 
    [x, q1]
    >= z & 
    [y, q1]
    >= z by 
    A1;
    
        reconsider z2 = (z
    `2 ) as 
    Element of D2 by 
    A2,
    MCART_1: 10;
    
        reconsider zz = (z
    `1 ) as 
    Element of D1 by 
    A2,
    MCART_1: 10;
    
        take zz;
    
        thus zz
    in D1; 
    
        ex x,y be
    object st x 
    in D1 & y 
    in D2 & z 
    =  
    [x, y] by
    A2,
    ZFMISC_1:def 2;
    
        then
    [x, q1]
    >=  
    [zz, z2] &
    [y, q1]
    >=  
    [zz, z2] by
    A3;
    
        hence thesis by
    Th11;
    
      end;
    
      set q1 = the
    Element of D1; 
    
      let x,y be
    Element of S2; 
    
      assume x
    in D2 & y 
    in D2; 
    
      then
    [q1, x]
    in  
    [:D1, D2:] &
    [q1, y]
    in  
    [:D1, D2:] by
    ZFMISC_1: 87;
    
      then
    
      consider z be
    Element of 
    [:S1, S2:] such that
    
      
    
    A4: z 
    in  
    [:D1, D2:] and
    
      
    
    A5: 
    [q1, x]
    >= z & 
    [q1, y]
    >= z by 
    A1;
    
      reconsider z2 = (z
    `1 ) as 
    Element of D1 by 
    A4,
    MCART_1: 10;
    
      reconsider zz = (z
    `2 ) as 
    Element of D2 by 
    A4,
    MCART_1: 10;
    
      take zz;
    
      thus zz
    in D2; 
    
      ex x,y be
    object st x 
    in D1 & y 
    in D2 & z 
    =  
    [x, y] by
    A4,
    ZFMISC_1:def 2;
    
      then
    [q1, x]
    >=  
    [z2, zz] &
    [q1, y]
    >=  
    [z2, zz] by
    A5;
    
      hence thesis by
    Th11;
    
    end;
    
    theorem :: 
    
    YELLOW_3:24
    
    for S1,S2 be non
    empty
    reflexive  
    RelStr holds for D be non 
    empty
    filtered  
    Subset of 
    [:S1, S2:] holds (
    proj1 D) is 
    filtered & ( 
    proj2 D) is 
    filtered
    
    proof
    
      let S1,S2 be non
    empty
    reflexive  
    RelStr, D be non 
    empty
    filtered  
    Subset of 
    [:S1, S2:];
    
      set D1 = (
    proj1 D), D2 = ( 
    proj2 D); 
    
      the
    carrier of 
    [:S1, S2:]
    =  
    [:the 
    carrier of S1, the 
    carrier of S2:] by 
    Def2;
    
      then
    
      
    
    A1: D 
    c=  
    [:(
    proj1 D), ( 
    proj2 D):] by 
    Th1;
    
      thus D1 is
    filtered
    
      proof
    
        let x,y be
    Element of S1; 
    
        assume that
    
        
    
    A2: x 
    in D1 and 
    
        
    
    A3: y 
    in D1; 
    
        consider q2 be
    object such that 
    
        
    
    A4: 
    [y, q2]
    in D by 
    A3,
    XTUPLE_0:def 12;
    
        reconsider D29 = D2 as non
    empty  
    Subset of S2 by 
    A2,
    FUNCT_5: 16;
    
        reconsider D19 = D1 as non
    empty  
    Subset of S1 by 
    A2;
    
        consider q1 be
    object such that 
    
        
    
    A5: 
    [x, q1]
    in D by 
    A2,
    XTUPLE_0:def 12;
    
        reconsider q2 as
    Element of D29 by 
    A4,
    XTUPLE_0:def 13;
    
        reconsider q1 as
    Element of D29 by 
    A5,
    XTUPLE_0:def 13;
    
        consider z be
    Element of 
    [:S1, S2:] such that
    
        
    
    A6: z 
    in D and 
    
        
    
    A7: 
    [x, q1]
    >= z & 
    [y, q2]
    >= z by 
    A5,
    A4,
    WAYBEL_0:def 2;
    
        reconsider z2 = (z
    `2 ) as 
    Element of D29 by 
    A1,
    A6,
    MCART_1: 10;
    
        reconsider zz = (z
    `1 ) as 
    Element of D19 by 
    A1,
    A6,
    MCART_1: 10;
    
        take zz;
    
        thus zz
    in D1; 
    
        ex x,y be
    object st x 
    in D19 & y 
    in D29 & z 
    =  
    [x, y] by
    A1,
    A6,
    ZFMISC_1:def 2;
    
        then z
    =  
    [zz, z2];
    
        hence thesis by
    A7,
    Th11;
    
      end;
    
      let x,y be
    Element of S2; 
    
      assume that
    
      
    
    A8: x 
    in D2 and 
    
      
    
    A9: y 
    in D2; 
    
      consider q2 be
    object such that 
    
      
    
    A10: 
    [q2, y]
    in D by 
    A9,
    XTUPLE_0:def 13;
    
      reconsider D29 = D2 as non
    empty  
    Subset of S2 by 
    A8;
    
      reconsider D19 = D1 as non
    empty  
    Subset of S1 by 
    A8,
    FUNCT_5: 16;
    
      consider q1 be
    object such that 
    
      
    
    A11: 
    [q1, x]
    in D by 
    A8,
    XTUPLE_0:def 13;
    
      reconsider q2 as
    Element of D19 by 
    A10,
    XTUPLE_0:def 12;
    
      reconsider q1 as
    Element of D19 by 
    A11,
    XTUPLE_0:def 12;
    
      consider z be
    Element of 
    [:S1, S2:] such that
    
      
    
    A12: z 
    in D and 
    
      
    
    A13: 
    [q1, x]
    >= z & 
    [q2, y]
    >= z by 
    A11,
    A10,
    WAYBEL_0:def 2;
    
      reconsider z2 = (z
    `1 ) as 
    Element of D19 by 
    A1,
    A12,
    MCART_1: 10;
    
      reconsider zz = (z
    `2 ) as 
    Element of D29 by 
    A1,
    A12,
    MCART_1: 10;
    
      take zz;
    
      thus zz
    in D2; 
    
      ex x,y be
    object st x 
    in D19 & y 
    in D29 & z 
    =  
    [x, y] by
    A1,
    A12,
    ZFMISC_1:def 2;
    
      then z
    =  
    [z2, zz];
    
      hence thesis by
    A13,
    Th11;
    
    end;
    
    registration
    
      let S1,S2 be
    RelStr, D1 be 
    upper  
    Subset of S1, D2 be 
    upper  
    Subset of S2; 
    
      cluster 
    [:D1, D2:] ->
    upper;
    
      coherence
    
      proof
    
        set X =
    [:D1, D2:];
    
        X is
    upper
    
        proof
    
          let x,y be
    Element of 
    [:S1, S2:];
    
          assume that
    
          
    
    A1: x 
    in X and 
    
          
    
    A2: x 
    <= y; 
    
          consider x1,x2 be
    object such that 
    
          
    
    A3: x1 
    in D1 and 
    
          
    
    A4: x2 
    in D2 and 
    
          
    
    A5: x 
    =  
    [x1, x2] by
    A1,
    ZFMISC_1:def 2;
    
          reconsider s1 = S1, s2 = S2 as non
    empty  
    RelStr by 
    A3,
    A4;
    
          set C1 = the
    carrier of s1, C2 = the 
    carrier of s2; 
    
          the
    carrier of 
    [:S1, S2:]
    =  
    [:C1, C2:] by
    Def2;
    
          then
    
          consider y1,y2 be
    object such that 
    
          
    
    A6: y1 
    in C1 and 
    
          
    
    A7: y2 
    in C2 and 
    
          
    
    A8: y 
    =  
    [y1, y2] by
    ZFMISC_1:def 2;
    
          reconsider x2, y2 as
    Element of s2 by 
    A4,
    A7;
    
          x2
    <= y2 by 
    A2,
    A3,
    A5,
    A6,
    A8,
    Th11;
    
          then
    
          
    
    A9: y2 
    in D2 by 
    A4,
    WAYBEL_0:def 20;
    
          reconsider x1, y1 as
    Element of s1 by 
    A3,
    A6;
    
          x1
    <= y1 by 
    A2,
    A4,
    A5,
    A7,
    A8,
    Th11;
    
          then y1
    in D1 by 
    A3,
    WAYBEL_0:def 20;
    
          hence thesis by
    A8,
    A9,
    ZFMISC_1: 87;
    
        end;
    
        hence thesis;
    
      end;
    
    end
    
    theorem :: 
    
    YELLOW_3:25
    
    for S1,S2 be non
    empty
    reflexive  
    RelStr holds for D1 be non 
    empty  
    Subset of S1, D2 be non 
    empty  
    Subset of S2 st 
    [:D1, D2:] is
    upper holds D1 is 
    upper & D2 is 
    upper
    
    proof
    
      let S1,S2 be non
    empty
    reflexive  
    RelStr, D1 be non 
    empty  
    Subset of S1, D2 be non 
    empty  
    Subset of S2 such that 
    
      
    
    A1: 
    [:D1, D2:] is
    upper;
    
      thus D1 is
    upper
    
      proof
    
        set q1 = the
    Element of D2; 
    
        let x,y be
    Element of S1; 
    
        assume that
    
        
    
    A2: x 
    in D1 and 
    
        
    
    A3: x 
    <= y; 
    
        
    
        
    
    A4: 
    [x, q1]
    in  
    [:D1, D2:] by
    A2,
    ZFMISC_1: 87;
    
        q1
    <= q1; 
    
        then
    [x, q1]
    <=  
    [y, q1] by
    A3,
    Th11;
    
        then
    [y, q1]
    in  
    [:D1, D2:] by
    A1,
    A4;
    
        hence thesis by
    ZFMISC_1: 87;
    
      end;
    
      set q1 = the
    Element of D1; 
    
      let x,y be
    Element of S2; 
    
      assume that
    
      
    
    A5: x 
    in D2 and 
    
      
    
    A6: x 
    <= y; 
    
      
    
      
    
    A7: 
    [q1, x]
    in  
    [:D1, D2:] by
    A5,
    ZFMISC_1: 87;
    
      q1
    <= q1; 
    
      then
    [q1, x]
    <=  
    [q1, y] by
    A6,
    Th11;
    
      then
    [q1, y]
    in  
    [:D1, D2:] by
    A1,
    A7;
    
      hence thesis by
    ZFMISC_1: 87;
    
    end;
    
    theorem :: 
    
    YELLOW_3:26
    
    for S1,S2 be non
    empty
    reflexive  
    RelStr holds for D be non 
    empty
    upper  
    Subset of 
    [:S1, S2:] holds (
    proj1 D) is 
    upper & ( 
    proj2 D) is 
    upper
    
    proof
    
      let S1,S2 be non
    empty
    reflexive  
    RelStr, D be non 
    empty
    upper  
    Subset of 
    [:S1, S2:];
    
      set D1 = (
    proj1 D), D2 = ( 
    proj2 D); 
    
      reconsider d1 = D1 as non
    empty  
    Subset of S1 by 
    Th21;
    
      the
    carrier of 
    [:S1, S2:]
    =  
    [:the 
    carrier of S1, the 
    carrier of S2:] by 
    Def2;
    
      then
    
      
    
    A1: D 
    c=  
    [:D1, D2:] by
    Th1;
    
      thus D1 is
    upper
    
      proof
    
        reconsider d2 = D2 as non
    empty  
    Subset of S2 by 
    Th21;
    
        let x,y be
    Element of S1 such that 
    
        
    
    A2: x 
    in D1 and 
    
        
    
    A3: x 
    <= y; 
    
        consider q1 be
    object such that 
    
        
    
    A4: 
    [x, q1]
    in D by 
    A2,
    XTUPLE_0:def 12;
    
        reconsider q1 as
    Element of d2 by 
    A1,
    A4,
    ZFMISC_1: 87;
    
        q1
    <= q1; 
    
        then
    [x, q1]
    <=  
    [y, q1] by
    A3,
    Th11;
    
        then
    [y, q1]
    in D by 
    A4,
    WAYBEL_0:def 20;
    
        hence thesis by
    A1,
    ZFMISC_1: 87;
    
      end;
    
      let x,y be
    Element of S2 such that 
    
      
    
    A5: x 
    in D2 and 
    
      
    
    A6: x 
    <= y; 
    
      consider q1 be
    object such that 
    
      
    
    A7: 
    [q1, x]
    in D by 
    A5,
    XTUPLE_0:def 13;
    
      reconsider q1 as
    Element of d1 by 
    A1,
    A7,
    ZFMISC_1: 87;
    
      q1
    <= q1; 
    
      then
    [q1, x]
    <=  
    [q1, y] by
    A6,
    Th11;
    
      then
    [q1, y]
    in D by 
    A7,
    WAYBEL_0:def 20;
    
      hence thesis by
    A1,
    ZFMISC_1: 87;
    
    end;
    
    registration
    
      let S1,S2 be
    RelStr, D1 be 
    lower  
    Subset of S1, D2 be 
    lower  
    Subset of S2; 
    
      cluster 
    [:D1, D2:] ->
    lower;
    
      coherence
    
      proof
    
        set X =
    [:D1, D2:];
    
        X is
    lower
    
        proof
    
          let x,y be
    Element of 
    [:S1, S2:];
    
          assume that
    
          
    
    A1: x 
    in X and 
    
          
    
    A2: x 
    >= y; 
    
          consider x1,x2 be
    object such that 
    
          
    
    A3: x1 
    in D1 and 
    
          
    
    A4: x2 
    in D2 and 
    
          
    
    A5: x 
    =  
    [x1, x2] by
    A1,
    ZFMISC_1:def 2;
    
          reconsider s1 = S1, s2 = S2 as non
    empty  
    RelStr by 
    A3,
    A4;
    
          set C1 = the
    carrier of s1, C2 = the 
    carrier of s2; 
    
          the
    carrier of 
    [:S1, S2:]
    =  
    [:C1, C2:] by
    Def2;
    
          then
    
          consider y1,y2 be
    object such that 
    
          
    
    A6: y1 
    in C1 and 
    
          
    
    A7: y2 
    in C2 and 
    
          
    
    A8: y 
    =  
    [y1, y2] by
    ZFMISC_1:def 2;
    
          reconsider x2, y2 as
    Element of s2 by 
    A4,
    A7;
    
          x2
    >= y2 by 
    A2,
    A3,
    A5,
    A6,
    A8,
    Th11;
    
          then
    
          
    
    A9: y2 
    in D2 by 
    A4,
    WAYBEL_0:def 19;
    
          reconsider x1, y1 as
    Element of s1 by 
    A3,
    A6;
    
          x1
    >= y1 by 
    A2,
    A4,
    A5,
    A7,
    A8,
    Th11;
    
          then y1
    in D1 by 
    A3,
    WAYBEL_0:def 19;
    
          hence thesis by
    A8,
    A9,
    ZFMISC_1: 87;
    
        end;
    
        hence thesis;
    
      end;
    
    end
    
    theorem :: 
    
    YELLOW_3:27
    
    for S1,S2 be non
    empty
    reflexive  
    RelStr holds for D1 be non 
    empty  
    Subset of S1, D2 be non 
    empty  
    Subset of S2 st 
    [:D1, D2:] is
    lower holds D1 is 
    lower & D2 is 
    lower
    
    proof
    
      let S1,S2 be non
    empty
    reflexive  
    RelStr, D1 be non 
    empty  
    Subset of S1, D2 be non 
    empty  
    Subset of S2 such that 
    
      
    
    A1: 
    [:D1, D2:] is
    lower;
    
      thus D1 is
    lower
    
      proof
    
        set q1 = the
    Element of D2; 
    
        let x,y be
    Element of S1; 
    
        assume that
    
        
    
    A2: x 
    in D1 and 
    
        
    
    A3: x 
    >= y; 
    
        
    
        
    
    A4: 
    [x, q1]
    in  
    [:D1, D2:] by
    A2,
    ZFMISC_1: 87;
    
        q1
    <= q1; 
    
        then
    [x, q1]
    >=  
    [y, q1] by
    A3,
    Th11;
    
        then
    [y, q1]
    in  
    [:D1, D2:] by
    A1,
    A4;
    
        hence thesis by
    ZFMISC_1: 87;
    
      end;
    
      set q1 = the
    Element of D1; 
    
      let x,y be
    Element of S2; 
    
      assume that
    
      
    
    A5: x 
    in D2 and 
    
      
    
    A6: x 
    >= y; 
    
      
    
      
    
    A7: 
    [q1, x]
    in  
    [:D1, D2:] by
    A5,
    ZFMISC_1: 87;
    
      q1
    <= q1; 
    
      then
    [q1, x]
    >=  
    [q1, y] by
    A6,
    Th11;
    
      then
    [q1, y]
    in  
    [:D1, D2:] by
    A1,
    A7;
    
      hence thesis by
    ZFMISC_1: 87;
    
    end;
    
    theorem :: 
    
    YELLOW_3:28
    
    for S1,S2 be non
    empty
    reflexive  
    RelStr holds for D be non 
    empty
    lower  
    Subset of 
    [:S1, S2:] holds (
    proj1 D) is 
    lower & ( 
    proj2 D) is 
    lower
    
    proof
    
      let S1,S2 be non
    empty
    reflexive  
    RelStr, D be non 
    empty
    lower  
    Subset of 
    [:S1, S2:];
    
      set D1 = (
    proj1 D), D2 = ( 
    proj2 D); 
    
      reconsider d1 = D1 as non
    empty  
    Subset of S1 by 
    Th21;
    
      the
    carrier of 
    [:S1, S2:]
    =  
    [:the 
    carrier of S1, the 
    carrier of S2:] by 
    Def2;
    
      then
    
      
    
    A1: D 
    c=  
    [:D1, D2:] by
    Th1;
    
      thus D1 is
    lower
    
      proof
    
        reconsider d2 = D2 as non
    empty  
    Subset of S2 by 
    Th21;
    
        let x,y be
    Element of S1 such that 
    
        
    
    A2: x 
    in D1 and 
    
        
    
    A3: x 
    >= y; 
    
        consider q1 be
    object such that 
    
        
    
    A4: 
    [x, q1]
    in D by 
    A2,
    XTUPLE_0:def 12;
    
        reconsider q1 as
    Element of d2 by 
    A1,
    A4,
    ZFMISC_1: 87;
    
        q1
    <= q1; 
    
        then
    [x, q1]
    >=  
    [y, q1] by
    A3,
    Th11;
    
        then
    [y, q1]
    in D by 
    A4,
    WAYBEL_0:def 19;
    
        hence thesis by
    A1,
    ZFMISC_1: 87;
    
      end;
    
      let x,y be
    Element of S2 such that 
    
      
    
    A5: x 
    in D2 and 
    
      
    
    A6: x 
    >= y; 
    
      consider q1 be
    object such that 
    
      
    
    A7: 
    [q1, x]
    in D by 
    A5,
    XTUPLE_0:def 13;
    
      reconsider q1 as
    Element of d1 by 
    A1,
    A7,
    ZFMISC_1: 87;
    
      q1
    <= q1; 
    
      then
    [q1, x]
    >=  
    [q1, y] by
    A6,
    Th11;
    
      then
    [q1, y]
    in D by 
    A7,
    WAYBEL_0:def 19;
    
      hence thesis by
    A1,
    ZFMISC_1: 87;
    
    end;
    
    definition
    
      let R be
    RelStr;
    
      :: 
    
    YELLOW_3:def3
    
      attr R is
    
    void means 
    
      :
    
    Def3: the 
    InternalRel of R is 
    empty;
    
    end
    
    registration
    
      cluster 
    empty -> 
    void for 
    RelStr;
    
      coherence ;
    
    end
    
    registration
    
      cluster non 
    void non 
    empty
    strict for 
    Poset;
    
      existence
    
      proof
    
        set R = the non
    empty
    strict  
    Poset;
    
        take R;
    
        (ex x be
    object st x 
    in the 
    carrier of R) & the 
    InternalRel of R 
    is_reflexive_in the 
    carrier of R by 
    ORDERS_2:def 2,
    XBOOLE_0:def 1;
    
        hence the
    InternalRel of R is non 
    empty;
    
        thus thesis;
    
      end;
    
    end
    
    registration
    
      cluster non 
    void -> non 
    empty for 
    RelStr;
    
      coherence ;
    
    end
    
    registration
    
      cluster non 
    empty
    reflexive -> non 
    void for 
    RelStr;
    
      coherence
    
      proof
    
        let R be
    RelStr;
    
        assume R is non
    empty
    reflexive;
    
        then
    
        reconsider R1 = R as non
    empty
    reflexive  
    RelStr;
    
        (ex x be
    object st x 
    in the 
    carrier of R1) & the 
    InternalRel of R1 
    is_reflexive_in the 
    carrier of R1 by 
    ORDERS_2:def 2,
    XBOOLE_0:def 1;
    
        hence the
    InternalRel of R is non 
    empty;
    
      end;
    
    end
    
    registration
    
      let R be non
    void  
    RelStr;
    
      cluster the 
    InternalRel of R -> non 
    empty;
    
      coherence by
    Def3;
    
    end
    
    theorem :: 
    
    YELLOW_3:29
    
    
    
    
    
    Th29: for S1,S2 be non 
    empty  
    RelStr holds for D1 be non 
    empty  
    Subset of S1, D2 be non 
    empty  
    Subset of S2 holds for x be 
    Element of S1, y be 
    Element of S2 st 
    [x, y]
    is_>=_than  
    [:D1, D2:] holds x
    is_>=_than D1 & y 
    is_>=_than D2 
    
    proof
    
      let S1,S2 be non
    empty  
    RelStr, D1 be non 
    empty  
    Subset of S1, D2 be non 
    empty  
    Subset of S2, x be 
    Element of S1, y be 
    Element of S2 such that 
    
      
    
    A1: 
    [x, y]
    is_>=_than  
    [:D1, D2:];
    
      thus x
    is_>=_than D1 
    
      proof
    
        set a = the
    Element of D2; 
    
        let b be
    Element of S1; 
    
        assume b
    in D1; 
    
        then
    [b, a]
    in  
    [:D1, D2:] by
    ZFMISC_1: 87;
    
        then
    [b, a]
    <=  
    [x, y] by
    A1;
    
        hence thesis by
    Th11;
    
      end;
    
      set b = the
    Element of D1; 
    
      let a be
    Element of S2; 
    
      assume a
    in D2; 
    
      then
    [b, a]
    in  
    [:D1, D2:] by
    ZFMISC_1: 87;
    
      then
    [b, a]
    <=  
    [x, y] by
    A1;
    
      hence thesis by
    Th11;
    
    end;
    
    theorem :: 
    
    YELLOW_3:30
    
    
    
    
    
    Th30: for S1,S2 be non 
    empty  
    RelStr holds for D1 be 
    Subset of S1, D2 be 
    Subset of S2 holds for x be 
    Element of S1, y be 
    Element of S2 st x 
    is_>=_than D1 & y 
    is_>=_than D2 holds 
    [x, y]
    is_>=_than  
    [:D1, D2:]
    
    proof
    
      let S1,S2 be non
    empty  
    RelStr, D1 be 
    Subset of S1, D2 be 
    Subset of S2, x be 
    Element of S1, y be 
    Element of S2 such that 
    
      
    
    A1: x 
    is_>=_than D1 & y 
    is_>=_than D2; 
    
      let b be
    Element of 
    [:S1, S2:];
    
      assume b
    in  
    [:D1, D2:];
    
      then
    
      consider b1,b2 be
    object such that 
    
      
    
    A2: b1 
    in D1 and 
    
      
    
    A3: b2 
    in D2 and 
    
      
    
    A4: b 
    =  
    [b1, b2] by
    ZFMISC_1:def 2;
    
      reconsider b2 as
    Element of S2 by 
    A3;
    
      reconsider b1 as
    Element of S1 by 
    A2;
    
      b1
    <= x & b2 
    <= y by 
    A1,
    A2,
    A3;
    
      hence thesis by
    A4,
    Th11;
    
    end;
    
    theorem :: 
    
    YELLOW_3:31
    
    
    
    
    
    Th31: for S1,S2 be non 
    empty  
    RelStr holds for D be 
    Subset of 
    [:S1, S2:] holds for x be
    Element of S1, y be 
    Element of S2 holds 
    [x, y]
    is_>=_than D iff x 
    is_>=_than ( 
    proj1 D) & y 
    is_>=_than ( 
    proj2 D) 
    
    proof
    
      let S1,S2 be non
    empty  
    RelStr, D be 
    Subset of 
    [:S1, S2:], x be
    Element of S1, y be 
    Element of S2; 
    
      set D1 = (
    proj1 D), D2 = ( 
    proj2 D); 
    
      hereby
    
        assume
    
        
    
    A1: 
    [x, y]
    is_>=_than D; 
    
        thus x
    is_>=_than D1 
    
        proof
    
          let q be
    Element of S1; 
    
          assume q
    in D1; 
    
          then
    
          consider z be
    object such that 
    
          
    
    A2: 
    [q, z]
    in D by 
    XTUPLE_0:def 12;
    
          reconsider d2 = D2 as non
    empty  
    Subset of S2 by 
    A2,
    XTUPLE_0:def 13;
    
          reconsider z as
    Element of d2 by 
    A2,
    XTUPLE_0:def 13;
    
          
    [x, y]
    >=  
    [q, z] by
    A1,
    A2;
    
          hence thesis by
    Th11;
    
        end;
    
        thus y
    is_>=_than D2 
    
        proof
    
          let q be
    Element of S2; 
    
          assume q
    in D2; 
    
          then
    
          consider z be
    object such that 
    
          
    
    A3: 
    [z, q]
    in D by 
    XTUPLE_0:def 13;
    
          reconsider d1 = D1 as non
    empty  
    Subset of S1 by 
    A3,
    XTUPLE_0:def 12;
    
          reconsider z as
    Element of d1 by 
    A3,
    XTUPLE_0:def 12;
    
          
    [x, y]
    >=  
    [z, q] by
    A1,
    A3;
    
          hence thesis by
    Th11;
    
        end;
    
      end;
    
      assume x
    is_>=_than ( 
    proj1 D) & y 
    is_>=_than ( 
    proj2 D); 
    
      then
    
      
    
    A4: 
    [x, y]
    is_>=_than  
    [:D1, D2:] by
    Th30;
    
      the
    carrier of 
    [:S1, S2:]
    =  
    [:the 
    carrier of S1, the 
    carrier of S2:] by 
    Def2;
    
      then D
    c=  
    [:D1, D2:] by
    Th1;
    
      hence thesis by
    A4;
    
    end;
    
    theorem :: 
    
    YELLOW_3:32
    
    
    
    
    
    Th32: for S1,S2 be non 
    empty  
    RelStr holds for D1 be non 
    empty  
    Subset of S1, D2 be non 
    empty  
    Subset of S2 holds for x be 
    Element of S1, y be 
    Element of S2 st 
    [x, y]
    is_<=_than  
    [:D1, D2:] holds x
    is_<=_than D1 & y 
    is_<=_than D2 
    
    proof
    
      let S1,S2 be non
    empty  
    RelStr, D1 be non 
    empty  
    Subset of S1, D2 be non 
    empty  
    Subset of S2, x be 
    Element of S1, y be 
    Element of S2 such that 
    
      
    
    A1: 
    [x, y]
    is_<=_than  
    [:D1, D2:];
    
      thus x
    is_<=_than D1 
    
      proof
    
        set a = the
    Element of D2; 
    
        let b be
    Element of S1; 
    
        assume b
    in D1; 
    
        then
    [b, a]
    in  
    [:D1, D2:] by
    ZFMISC_1: 87;
    
        then
    [b, a]
    >=  
    [x, y] by
    A1;
    
        hence thesis by
    Th11;
    
      end;
    
      set b = the
    Element of D1; 
    
      let a be
    Element of S2; 
    
      assume a
    in D2; 
    
      then
    [b, a]
    in  
    [:D1, D2:] by
    ZFMISC_1: 87;
    
      then
    [b, a]
    >=  
    [x, y] by
    A1;
    
      hence thesis by
    Th11;
    
    end;
    
    theorem :: 
    
    YELLOW_3:33
    
    
    
    
    
    Th33: for S1,S2 be non 
    empty  
    RelStr holds for D1 be 
    Subset of S1, D2 be 
    Subset of S2 holds for x be 
    Element of S1, y be 
    Element of S2 st x 
    is_<=_than D1 & y 
    is_<=_than D2 holds 
    [x, y]
    is_<=_than  
    [:D1, D2:]
    
    proof
    
      let S1,S2 be non
    empty  
    RelStr, D1 be 
    Subset of S1, D2 be 
    Subset of S2, x be 
    Element of S1, y be 
    Element of S2 such that 
    
      
    
    A1: x 
    is_<=_than D1 & y 
    is_<=_than D2; 
    
      let b be
    Element of 
    [:S1, S2:];
    
      assume b
    in  
    [:D1, D2:];
    
      then
    
      consider b1,b2 be
    object such that 
    
      
    
    A2: b1 
    in D1 and 
    
      
    
    A3: b2 
    in D2 and 
    
      
    
    A4: b 
    =  
    [b1, b2] by
    ZFMISC_1:def 2;
    
      reconsider b2 as
    Element of S2 by 
    A3;
    
      reconsider b1 as
    Element of S1 by 
    A2;
    
      b1
    >= x & b2 
    >= y by 
    A1,
    A2,
    A3;
    
      hence thesis by
    A4,
    Th11;
    
    end;
    
    theorem :: 
    
    YELLOW_3:34
    
    
    
    
    
    Th34: for S1,S2 be non 
    empty  
    RelStr holds for D be 
    Subset of 
    [:S1, S2:] holds for x be
    Element of S1, y be 
    Element of S2 holds 
    [x, y]
    is_<=_than D iff x 
    is_<=_than ( 
    proj1 D) & y 
    is_<=_than ( 
    proj2 D) 
    
    proof
    
      let S1,S2 be non
    empty  
    RelStr, D be 
    Subset of 
    [:S1, S2:], x be
    Element of S1, y be 
    Element of S2; 
    
      set D1 = (
    proj1 D), D2 = ( 
    proj2 D); 
    
      hereby
    
        assume
    
        
    
    A1: 
    [x, y]
    is_<=_than D; 
    
        thus x
    is_<=_than D1 
    
        proof
    
          let q be
    Element of S1; 
    
          assume q
    in D1; 
    
          then
    
          consider z be
    object such that 
    
          
    
    A2: 
    [q, z]
    in D by 
    XTUPLE_0:def 12;
    
          reconsider d2 = D2 as non
    empty  
    Subset of S2 by 
    A2,
    XTUPLE_0:def 13;
    
          reconsider z as
    Element of d2 by 
    A2,
    XTUPLE_0:def 13;
    
          
    [x, y]
    <=  
    [q, z] by
    A1,
    A2;
    
          hence thesis by
    Th11;
    
        end;
    
        thus y
    is_<=_than D2 
    
        proof
    
          let q be
    Element of S2; 
    
          assume q
    in D2; 
    
          then
    
          consider z be
    object such that 
    
          
    
    A3: 
    [z, q]
    in D by 
    XTUPLE_0:def 13;
    
          reconsider d1 = D1 as non
    empty  
    Subset of S1 by 
    A3,
    XTUPLE_0:def 12;
    
          reconsider z as
    Element of d1 by 
    A3,
    XTUPLE_0:def 12;
    
          
    [x, y]
    <=  
    [z, q] by
    A1,
    A3;
    
          hence thesis by
    Th11;
    
        end;
    
      end;
    
      assume x
    is_<=_than ( 
    proj1 D) & y 
    is_<=_than ( 
    proj2 D); 
    
      then
    
      
    
    A4: 
    [x, y]
    is_<=_than  
    [:D1, D2:] by
    Th33;
    
      the
    carrier of 
    [:S1, S2:]
    =  
    [:the 
    carrier of S1, the 
    carrier of S2:] by 
    Def2;
    
      then D
    c=  
    [:D1, D2:] by
    Th1;
    
      hence thesis by
    A4;
    
    end;
    
    theorem :: 
    
    YELLOW_3:35
    
    
    
    
    
    Th35: for S1,S2 be 
    antisymmetric non 
    empty  
    RelStr holds for D1 be 
    Subset of S1, D2 be 
    Subset of S2 holds for x be 
    Element of S1, y be 
    Element of S2 st 
    ex_sup_of (D1,S1) & 
    ex_sup_of (D2,S2) & for b be 
    Element of 
    [:S1, S2:] st b
    is_>=_than  
    [:D1, D2:] holds
    [x, y]
    <= b holds (for c be 
    Element of S1 st c 
    is_>=_than D1 holds x 
    <= c) & for d be 
    Element of S2 st d 
    is_>=_than D2 holds y 
    <= d 
    
    proof
    
      let S1,S2 be
    antisymmetric non 
    empty  
    RelStr, D1 be 
    Subset of S1, D2 be 
    Subset of S2, x be 
    Element of S1, y be 
    Element of S2 such that 
    
      
    
    A1: 
    ex_sup_of (D1,S1) and 
    
      
    
    A2: 
    ex_sup_of (D2,S2) and 
    
      
    
    A3: for b be 
    Element of 
    [:S1, S2:] st b
    is_>=_than  
    [:D1, D2:] holds
    [x, y]
    <= b; 
    
      thus for c be
    Element of S1 st c 
    is_>=_than D1 holds x 
    <= c 
    
      proof
    
        
    
        
    
    A4: ( 
    sup D2) 
    is_>=_than D2 by 
    A2,
    YELLOW_0: 30;
    
        let b be
    Element of S1; 
    
        assume b
    is_>=_than D1; 
    
        then
    [x, y]
    <=  
    [b, (
    sup D2)] by 
    A3,
    A4,
    Th30;
    
        hence thesis by
    Th11;
    
      end;
    
      
    
      
    
    A5: ( 
    sup D1) 
    is_>=_than D1 by 
    A1,
    YELLOW_0: 30;
    
      let b be
    Element of S2; 
    
      assume b
    is_>=_than D2; 
    
      then
    [x, y]
    <=  
    [(
    sup D1), b] by 
    A3,
    A5,
    Th30;
    
      hence thesis by
    Th11;
    
    end;
    
    theorem :: 
    
    YELLOW_3:36
    
    
    
    
    
    Th36: for S1,S2 be 
    antisymmetric non 
    empty  
    RelStr holds for D1 be 
    Subset of S1, D2 be 
    Subset of S2 holds for x be 
    Element of S1, y be 
    Element of S2 st 
    ex_inf_of (D1,S1) & 
    ex_inf_of (D2,S2) & for b be 
    Element of 
    [:S1, S2:] st b
    is_<=_than  
    [:D1, D2:] holds
    [x, y]
    >= b holds (for c be 
    Element of S1 st c 
    is_<=_than D1 holds x 
    >= c) & for d be 
    Element of S2 st d 
    is_<=_than D2 holds y 
    >= d 
    
    proof
    
      let S1,S2 be
    antisymmetric non 
    empty  
    RelStr, D1 be 
    Subset of S1, D2 be 
    Subset of S2, x be 
    Element of S1, y be 
    Element of S2 such that 
    
      
    
    A1: 
    ex_inf_of (D1,S1) and 
    
      
    
    A2: 
    ex_inf_of (D2,S2) and 
    
      
    
    A3: for b be 
    Element of 
    [:S1, S2:] st b
    is_<=_than  
    [:D1, D2:] holds
    [x, y]
    >= b; 
    
      thus for c be
    Element of S1 st c 
    is_<=_than D1 holds x 
    >= c 
    
      proof
    
        
    
        
    
    A4: ( 
    inf D2) 
    is_<=_than D2 by 
    A2,
    YELLOW_0: 31;
    
        let b be
    Element of S1; 
    
        assume b
    is_<=_than D1; 
    
        then
    [x, y]
    >=  
    [b, (
    inf D2)] by 
    A3,
    A4,
    Th33;
    
        hence thesis by
    Th11;
    
      end;
    
      
    
      
    
    A5: ( 
    inf D1) 
    is_<=_than D1 by 
    A1,
    YELLOW_0: 31;
    
      let b be
    Element of S2; 
    
      assume b
    is_<=_than D2; 
    
      then
    [x, y]
    >=  
    [(
    inf D1), b] by 
    A3,
    A5,
    Th33;
    
      hence thesis by
    Th11;
    
    end;
    
    theorem :: 
    
    YELLOW_3:37
    
    for S1,S2 be
    antisymmetric non 
    empty  
    RelStr holds for D1 be non 
    empty  
    Subset of S1, D2 be non 
    empty  
    Subset of S2 holds for x be 
    Element of S1, y be 
    Element of S2 st (for c be 
    Element of S1 st c 
    is_>=_than D1 holds x 
    <= c) & for d be 
    Element of S2 st d 
    is_>=_than D2 holds y 
    <= d holds for b be 
    Element of 
    [:S1, S2:] st b
    is_>=_than  
    [:D1, D2:] holds
    [x, y]
    <= b 
    
    proof
    
      let S1,S2 be
    antisymmetric non 
    empty  
    RelStr, D1 be non 
    empty  
    Subset of S1, D2 be non 
    empty  
    Subset of S2, x be 
    Element of S1, y be 
    Element of S2 such that 
    
      
    
    A1: for c be 
    Element of S1 st c 
    is_>=_than D1 holds x 
    <= c and 
    
      
    
    A2: for d be 
    Element of S2 st d 
    is_>=_than D2 holds y 
    <= d; 
    
      let b be
    Element of 
    [:S1, S2:] such that
    
      
    
    A3: b 
    is_>=_than  
    [:D1, D2:];
    
      the
    carrier of 
    [:S1, S2:]
    =  
    [:the 
    carrier of S1, the 
    carrier of S2:] by 
    Def2;
    
      then ex c,d be
    object st c 
    in the 
    carrier of S1 & d 
    in the 
    carrier of S2 & b 
    =  
    [c, d] by
    ZFMISC_1:def 2;
    
      then
    
      
    
    A4: b 
    =  
    [(b
    `1 ), (b 
    `2 )]; 
    
      then (b
    `2 ) 
    is_>=_than D2 by 
    A3,
    Th29;
    
      then
    
      
    
    A5: y 
    <= (b 
    `2 ) by 
    A2;
    
      (b
    `1 ) 
    is_>=_than D1 by 
    A3,
    A4,
    Th29;
    
      then x
    <= (b 
    `1 ) by 
    A1;
    
      hence thesis by
    A4,
    A5,
    Th11;
    
    end;
    
    theorem :: 
    
    YELLOW_3:38
    
    for S1,S2 be
    antisymmetric non 
    empty  
    RelStr holds for D1 be non 
    empty  
    Subset of S1, D2 be non 
    empty  
    Subset of S2 holds for x be 
    Element of S1, y be 
    Element of S2 st (for c be 
    Element of S1 st c 
    is_>=_than D1 holds x 
    >= c) & for d be 
    Element of S2 st d 
    is_>=_than D2 holds y 
    >= d holds for b be 
    Element of 
    [:S1, S2:] st b
    is_>=_than  
    [:D1, D2:] holds
    [x, y]
    >= b 
    
    proof
    
      let S1,S2 be
    antisymmetric non 
    empty  
    RelStr, D1 be non 
    empty  
    Subset of S1, D2 be non 
    empty  
    Subset of S2, x be 
    Element of S1, y be 
    Element of S2 such that 
    
      
    
    A1: for c be 
    Element of S1 st c 
    is_>=_than D1 holds x 
    >= c and 
    
      
    
    A2: for d be 
    Element of S2 st d 
    is_>=_than D2 holds y 
    >= d; 
    
      let b be
    Element of 
    [:S1, S2:] such that
    
      
    
    A3: b 
    is_>=_than  
    [:D1, D2:];
    
      the
    carrier of 
    [:S1, S2:]
    =  
    [:the 
    carrier of S1, the 
    carrier of S2:] by 
    Def2;
    
      then ex c,d be
    object st c 
    in the 
    carrier of S1 & d 
    in the 
    carrier of S2 & b 
    =  
    [c, d] by
    ZFMISC_1:def 2;
    
      then
    
      
    
    A4: b 
    =  
    [(b
    `1 ), (b 
    `2 )]; 
    
      then (b
    `2 ) 
    is_>=_than D2 by 
    A3,
    Th29;
    
      then
    
      
    
    A5: y 
    >= (b 
    `2 ) by 
    A2;
    
      (b
    `1 ) 
    is_>=_than D1 by 
    A3,
    A4,
    Th29;
    
      then x
    >= (b 
    `1 ) by 
    A1;
    
      hence thesis by
    A4,
    A5,
    Th11;
    
    end;
    
    theorem :: 
    
    YELLOW_3:39
    
    
    
    
    
    Th39: for S1,S2 be 
    antisymmetric non 
    empty  
    RelStr holds for D1 be non 
    empty  
    Subset of S1, D2 be non 
    empty  
    Subset of S2 holds 
    ex_sup_of (D1,S1) & 
    ex_sup_of (D2,S2) iff 
    ex_sup_of ( 
    [:D1, D2:],
    [:S1, S2:])
    
    proof
    
      let S1,S2 be
    antisymmetric non 
    empty  
    RelStr, D1 be non 
    empty  
    Subset of S1, D2 be non 
    empty  
    Subset of S2; 
    
      hereby
    
        assume that
    
        
    
    A1: 
    ex_sup_of (D1,S1) and 
    
        
    
    A2: 
    ex_sup_of (D2,S2); 
    
        consider a2 be
    Element of S2 such that 
    
        
    
    A3: D2 
    is_<=_than a2 and 
    
        
    
    A4: for b be 
    Element of S2 st D2 
    is_<=_than b holds a2 
    <= b by 
    A2,
    YELLOW_0: 15;
    
        consider a1 be
    Element of S1 such that 
    
        
    
    A5: D1 
    is_<=_than a1 and 
    
        
    
    A6: for b be 
    Element of S1 st D1 
    is_<=_than b holds a1 
    <= b by 
    A1,
    YELLOW_0: 15;
    
        ex a be
    Element of 
    [:S1, S2:] st
    [:D1, D2:]
    is_<=_than a & for b be 
    Element of 
    [:S1, S2:] st
    [:D1, D2:]
    is_<=_than b holds a 
    <= b 
    
        proof
    
          take a =
    [a1, a2];
    
          thus
    [:D1, D2:]
    is_<=_than a by 
    A5,
    A3,
    Th30;
    
          let b be
    Element of 
    [:S1, S2:] such that
    
          
    
    A7: 
    [:D1, D2:]
    is_<=_than b; 
    
          the
    carrier of 
    [:S1, S2:]
    =  
    [:the 
    carrier of S1, the 
    carrier of S2:] by 
    Def2;
    
          then
    
          
    
    A8: b 
    =  
    [(b
    `1 ), (b 
    `2 )] by 
    MCART_1: 21;
    
          then D2
    is_<=_than (b 
    `2 ) by 
    A7,
    Th29;
    
          then
    
          
    
    A9: a2 
    <= (b 
    `2 ) by 
    A4;
    
          D1
    is_<=_than (b 
    `1 ) by 
    A7,
    A8,
    Th29;
    
          then a1
    <= (b 
    `1 ) by 
    A6;
    
          hence thesis by
    A8,
    A9,
    Th11;
    
        end;
    
        hence
    ex_sup_of ( 
    [:D1, D2:],
    [:S1, S2:]) by
    YELLOW_0: 15;
    
      end;
    
      assume
    ex_sup_of ( 
    [:D1, D2:],
    [:S1, S2:]);
    
      then
    
      consider x be
    Element of 
    [:S1, S2:] such that
    
      
    
    A10: 
    [:D1, D2:]
    is_<=_than x and 
    
      
    
    A11: for b be 
    Element of 
    [:S1, S2:] st
    [:D1, D2:]
    is_<=_than b holds x 
    <= b by 
    YELLOW_0: 15;
    
      the
    carrier of 
    [:S1, S2:]
    =  
    [:the 
    carrier of S1, the 
    carrier of S2:] by 
    Def2;
    
      then
    
      
    
    A12: x 
    =  
    [(x
    `1 ), (x 
    `2 )] by 
    MCART_1: 21;
    
      then
    
      
    
    A13: D1 
    is_<=_than (x 
    `1 ) by 
    A10,
    Th29;
    
      
    
      
    
    A14: D2 
    is_<=_than (x 
    `2 ) by 
    A10,
    A12,
    Th29;
    
      for b be
    Element of S1 st D1 
    is_<=_than b holds (x 
    `1 ) 
    <= b 
    
      proof
    
        let b be
    Element of S1; 
    
        assume D1
    is_<=_than b; 
    
        then x
    <=  
    [b, (x
    `2 )] by 
    A11,
    A14,
    Th30;
    
        hence thesis by
    A12,
    Th11;
    
      end;
    
      hence
    ex_sup_of (D1,S1) by 
    A13,
    YELLOW_0: 15;
    
      for b be
    Element of S2 st D2 
    is_<=_than b holds (x 
    `2 ) 
    <= b 
    
      proof
    
        let b be
    Element of S2; 
    
        assume D2
    is_<=_than b; 
    
        then x
    <=  
    [(x
    `1 ), b] by 
    A11,
    A13,
    Th30;
    
        hence thesis by
    A12,
    Th11;
    
      end;
    
      hence thesis by
    A14,
    YELLOW_0: 15;
    
    end;
    
    theorem :: 
    
    YELLOW_3:40
    
    
    
    
    
    Th40: for S1,S2 be 
    antisymmetric non 
    empty  
    RelStr holds for D1 be non 
    empty  
    Subset of S1, D2 be non 
    empty  
    Subset of S2 holds 
    ex_inf_of (D1,S1) & 
    ex_inf_of (D2,S2) iff 
    ex_inf_of ( 
    [:D1, D2:],
    [:S1, S2:])
    
    proof
    
      let S1,S2 be
    antisymmetric non 
    empty  
    RelStr, D1 be non 
    empty  
    Subset of S1, D2 be non 
    empty  
    Subset of S2; 
    
      hereby
    
        assume that
    
        
    
    A1: 
    ex_inf_of (D1,S1) and 
    
        
    
    A2: 
    ex_inf_of (D2,S2); 
    
        consider a2 be
    Element of S2 such that 
    
        
    
    A3: D2 
    is_>=_than a2 and 
    
        
    
    A4: for b be 
    Element of S2 st D2 
    is_>=_than b holds a2 
    >= b by 
    A2,
    YELLOW_0: 16;
    
        consider a1 be
    Element of S1 such that 
    
        
    
    A5: D1 
    is_>=_than a1 and 
    
        
    
    A6: for b be 
    Element of S1 st D1 
    is_>=_than b holds a1 
    >= b by 
    A1,
    YELLOW_0: 16;
    
        ex a be
    Element of 
    [:S1, S2:] st
    [:D1, D2:]
    is_>=_than a & for b be 
    Element of 
    [:S1, S2:] st
    [:D1, D2:]
    is_>=_than b holds a 
    >= b 
    
        proof
    
          take a =
    [a1, a2];
    
          thus
    [:D1, D2:]
    is_>=_than a by 
    A5,
    A3,
    Th33;
    
          let b be
    Element of 
    [:S1, S2:] such that
    
          
    
    A7: 
    [:D1, D2:]
    is_>=_than b; 
    
          the
    carrier of 
    [:S1, S2:]
    =  
    [:the 
    carrier of S1, the 
    carrier of S2:] by 
    Def2;
    
          then
    
          
    
    A8: b 
    =  
    [(b
    `1 ), (b 
    `2 )] by 
    MCART_1: 21;
    
          then D2
    is_>=_than (b 
    `2 ) by 
    A7,
    Th32;
    
          then
    
          
    
    A9: a2 
    >= (b 
    `2 ) by 
    A4;
    
          D1
    is_>=_than (b 
    `1 ) by 
    A7,
    A8,
    Th32;
    
          then a1
    >= (b 
    `1 ) by 
    A6;
    
          hence thesis by
    A8,
    A9,
    Th11;
    
        end;
    
        hence
    ex_inf_of ( 
    [:D1, D2:],
    [:S1, S2:]) by
    YELLOW_0: 16;
    
      end;
    
      assume
    ex_inf_of ( 
    [:D1, D2:],
    [:S1, S2:]);
    
      then
    
      consider x be
    Element of 
    [:S1, S2:] such that
    
      
    
    A10: 
    [:D1, D2:]
    is_>=_than x and 
    
      
    
    A11: for b be 
    Element of 
    [:S1, S2:] st
    [:D1, D2:]
    is_>=_than b holds x 
    >= b by 
    YELLOW_0: 16;
    
      the
    carrier of 
    [:S1, S2:]
    =  
    [:the 
    carrier of S1, the 
    carrier of S2:] by 
    Def2;
    
      then
    
      
    
    A12: x 
    =  
    [(x
    `1 ), (x 
    `2 )] by 
    MCART_1: 21;
    
      then
    
      
    
    A13: D1 
    is_>=_than (x 
    `1 ) by 
    A10,
    Th32;
    
      
    
      
    
    A14: D2 
    is_>=_than (x 
    `2 ) by 
    A10,
    A12,
    Th32;
    
      for b be
    Element of S1 st D1 
    is_>=_than b holds (x 
    `1 ) 
    >= b 
    
      proof
    
        let b be
    Element of S1; 
    
        assume D1
    is_>=_than b; 
    
        then x
    >=  
    [b, (x
    `2 )] by 
    A11,
    A14,
    Th33;
    
        hence thesis by
    A12,
    Th11;
    
      end;
    
      hence
    ex_inf_of (D1,S1) by 
    A13,
    YELLOW_0: 16;
    
      for b be
    Element of S2 st D2 
    is_>=_than b holds (x 
    `2 ) 
    >= b 
    
      proof
    
        let b be
    Element of S2; 
    
        assume D2
    is_>=_than b; 
    
        then x
    >=  
    [(x
    `1 ), b] by 
    A11,
    A13,
    Th33;
    
        hence thesis by
    A12,
    Th11;
    
      end;
    
      hence thesis by
    A14,
    YELLOW_0: 16;
    
    end;
    
    theorem :: 
    
    YELLOW_3:41
    
    
    
    
    
    Th41: for S1,S2 be 
    antisymmetric non 
    empty  
    RelStr holds for D be 
    Subset of 
    [:S1, S2:] holds
    ex_sup_of (( 
    proj1 D),S1) & 
    ex_sup_of (( 
    proj2 D),S2) iff 
    ex_sup_of (D, 
    [:S1, S2:])
    
    proof
    
      let S1,S2 be
    antisymmetric non 
    empty  
    RelStr, D be 
    Subset of 
    [:S1, S2:];
    
      
    
      
    
    A1: the 
    carrier of 
    [:S1, S2:]
    =  
    [:the 
    carrier of S1, the 
    carrier of S2:] by 
    Def2;
    
      then
    
      
    
    A2: D 
    c=  
    [:(
    proj1 D), ( 
    proj2 D):] by 
    Th1;
    
      hereby
    
        assume that
    
        
    
    A3: 
    ex_sup_of (( 
    proj1 D),S1) and 
    
        
    
    A4: 
    ex_sup_of (( 
    proj2 D),S2); 
    
        ex a be
    Element of 
    [:S1, S2:] st D
    is_<=_than a & for b be 
    Element of 
    [:S1, S2:] st D
    is_<=_than b holds a 
    <= b 
    
        proof
    
          consider x2 be
    Element of S2 such that 
    
          
    
    A5: ( 
    proj2 D) 
    is_<=_than x2 and 
    
          
    
    A6: for b be 
    Element of S2 st ( 
    proj2 D) 
    is_<=_than b holds x2 
    <= b by 
    A4,
    YELLOW_0: 15;
    
          consider x1 be
    Element of S1 such that 
    
          
    
    A7: ( 
    proj1 D) 
    is_<=_than x1 and 
    
          
    
    A8: for b be 
    Element of S1 st ( 
    proj1 D) 
    is_<=_than b holds x1 
    <= b by 
    A3,
    YELLOW_0: 15;
    
          take a =
    [x1, x2];
    
          thus D
    is_<=_than a 
    
          proof
    
            let q be
    Element of 
    [:S1, S2:];
    
            assume q
    in D; 
    
            then
    
            consider q1,q2 be
    object such that 
    
            
    
    A9: q1 
    in ( 
    proj1 D) and 
    
            
    
    A10: q2 
    in ( 
    proj2 D) and 
    
            
    
    A11: q 
    =  
    [q1, q2] by
    A2,
    ZFMISC_1:def 2;
    
            reconsider q2 as
    Element of S2 by 
    A10;
    
            reconsider q1 as
    Element of S1 by 
    A9;
    
            q1
    <= x1 & q2 
    <= x2 by 
    A7,
    A5,
    A9,
    A10;
    
            hence thesis by
    A11,
    Th11;
    
          end;
    
          let b be
    Element of 
    [:S1, S2:] such that
    
          
    
    A12: D 
    is_<=_than b; 
    
          
    
          
    
    A13: b 
    =  
    [(b
    `1 ), (b 
    `2 )] by 
    A1,
    MCART_1: 21;
    
          then (
    proj2 D) 
    is_<=_than (b 
    `2 ) by 
    A12,
    Th31;
    
          then
    
          
    
    A14: x2 
    <= (b 
    `2 ) by 
    A6;
    
          (
    proj1 D) 
    is_<=_than (b 
    `1 ) by 
    A12,
    A13,
    Th31;
    
          then x1
    <= (b 
    `1 ) by 
    A8;
    
          hence thesis by
    A13,
    A14,
    Th11;
    
        end;
    
        hence
    ex_sup_of (D, 
    [:S1, S2:]) by
    YELLOW_0: 15;
    
      end;
    
      assume
    ex_sup_of (D, 
    [:S1, S2:]);
    
      then
    
      consider x be
    Element of 
    [:S1, S2:] such that
    
      
    
    A15: D 
    is_<=_than x and 
    
      
    
    A16: for b be 
    Element of 
    [:S1, S2:] st D
    is_<=_than b holds x 
    <= b by 
    YELLOW_0: 15;
    
      
    
      
    
    A17: x 
    =  
    [(x
    `1 ), (x 
    `2 )] by 
    A1,
    MCART_1: 21;
    
      then
    
      
    
    A18: ( 
    proj1 D) 
    is_<=_than (x 
    `1 ) by 
    A15,
    Th31;
    
      
    
      
    
    A19: ( 
    proj2 D) 
    is_<=_than (x 
    `2 ) by 
    A15,
    A17,
    Th31;
    
      for b be
    Element of S1 st ( 
    proj1 D) 
    is_<=_than b holds (x 
    `1 ) 
    <= b 
    
      proof
    
        let b be
    Element of S1; 
    
        assume (
    proj1 D) 
    is_<=_than b; 
    
        then D
    is_<=_than  
    [b, (x
    `2 )] by 
    A19,
    Th31;
    
        then x
    <=  
    [b, (x
    `2 )] by 
    A16;
    
        hence thesis by
    A17,
    Th11;
    
      end;
    
      hence
    ex_sup_of (( 
    proj1 D),S1) by 
    A18,
    YELLOW_0: 15;
    
      for b be
    Element of S2 st ( 
    proj2 D) 
    is_<=_than b holds (x 
    `2 ) 
    <= b 
    
      proof
    
        let b be
    Element of S2; 
    
        assume (
    proj2 D) 
    is_<=_than b; 
    
        then D
    is_<=_than  
    [(x
    `1 ), b] by 
    A18,
    Th31;
    
        then x
    <=  
    [(x
    `1 ), b] by 
    A16;
    
        hence thesis by
    A17,
    Th11;
    
      end;
    
      hence thesis by
    A19,
    YELLOW_0: 15;
    
    end;
    
    theorem :: 
    
    YELLOW_3:42
    
    
    
    
    
    Th42: for S1,S2 be 
    antisymmetric non 
    empty  
    RelStr holds for D be 
    Subset of 
    [:S1, S2:] holds
    ex_inf_of (( 
    proj1 D),S1) & 
    ex_inf_of (( 
    proj2 D),S2) iff 
    ex_inf_of (D, 
    [:S1, S2:])
    
    proof
    
      let S1,S2 be
    antisymmetric non 
    empty  
    RelStr, D be 
    Subset of 
    [:S1, S2:];
    
      
    
      
    
    A1: the 
    carrier of 
    [:S1, S2:]
    =  
    [:the 
    carrier of S1, the 
    carrier of S2:] by 
    Def2;
    
      then
    
      
    
    A2: D 
    c=  
    [:(
    proj1 D), ( 
    proj2 D):] by 
    Th1;
    
      hereby
    
        assume that
    
        
    
    A3: 
    ex_inf_of (( 
    proj1 D),S1) and 
    
        
    
    A4: 
    ex_inf_of (( 
    proj2 D),S2); 
    
        ex a be
    Element of 
    [:S1, S2:] st D
    is_>=_than a & for b be 
    Element of 
    [:S1, S2:] st D
    is_>=_than b holds a 
    >= b 
    
        proof
    
          consider x2 be
    Element of S2 such that 
    
          
    
    A5: ( 
    proj2 D) 
    is_>=_than x2 and 
    
          
    
    A6: for b be 
    Element of S2 st ( 
    proj2 D) 
    is_>=_than b holds x2 
    >= b by 
    A4,
    YELLOW_0: 16;
    
          consider x1 be
    Element of S1 such that 
    
          
    
    A7: ( 
    proj1 D) 
    is_>=_than x1 and 
    
          
    
    A8: for b be 
    Element of S1 st ( 
    proj1 D) 
    is_>=_than b holds x1 
    >= b by 
    A3,
    YELLOW_0: 16;
    
          take a =
    [x1, x2];
    
          thus D
    is_>=_than a 
    
          proof
    
            let q be
    Element of 
    [:S1, S2:];
    
            assume q
    in D; 
    
            then
    
            consider q1,q2 be
    object such that 
    
            
    
    A9: q1 
    in ( 
    proj1 D) and 
    
            
    
    A10: q2 
    in ( 
    proj2 D) and 
    
            
    
    A11: q 
    =  
    [q1, q2] by
    A2,
    ZFMISC_1:def 2;
    
            reconsider q2 as
    Element of S2 by 
    A10;
    
            reconsider q1 as
    Element of S1 by 
    A9;
    
            q1
    >= x1 & q2 
    >= x2 by 
    A7,
    A5,
    A9,
    A10;
    
            hence thesis by
    A11,
    Th11;
    
          end;
    
          let b be
    Element of 
    [:S1, S2:] such that
    
          
    
    A12: D 
    is_>=_than b; 
    
          
    
          
    
    A13: b 
    =  
    [(b
    `1 ), (b 
    `2 )] by 
    A1,
    MCART_1: 21;
    
          then (
    proj2 D) 
    is_>=_than (b 
    `2 ) by 
    A12,
    Th34;
    
          then
    
          
    
    A14: x2 
    >= (b 
    `2 ) by 
    A6;
    
          (
    proj1 D) 
    is_>=_than (b 
    `1 ) by 
    A12,
    A13,
    Th34;
    
          then x1
    >= (b 
    `1 ) by 
    A8;
    
          hence thesis by
    A13,
    A14,
    Th11;
    
        end;
    
        hence
    ex_inf_of (D, 
    [:S1, S2:]) by
    YELLOW_0: 16;
    
      end;
    
      assume
    ex_inf_of (D, 
    [:S1, S2:]);
    
      then
    
      consider x be
    Element of 
    [:S1, S2:] such that
    
      
    
    A15: D 
    is_>=_than x and 
    
      
    
    A16: for b be 
    Element of 
    [:S1, S2:] st D
    is_>=_than b holds x 
    >= b by 
    YELLOW_0: 16;
    
      
    
      
    
    A17: x 
    =  
    [(x
    `1 ), (x 
    `2 )] by 
    A1,
    MCART_1: 21;
    
      then
    
      
    
    A18: ( 
    proj1 D) 
    is_>=_than (x 
    `1 ) by 
    A15,
    Th34;
    
      
    
      
    
    A19: ( 
    proj2 D) 
    is_>=_than (x 
    `2 ) by 
    A15,
    A17,
    Th34;
    
      for b be
    Element of S1 st ( 
    proj1 D) 
    is_>=_than b holds (x 
    `1 ) 
    >= b 
    
      proof
    
        let b be
    Element of S1; 
    
        assume (
    proj1 D) 
    is_>=_than b; 
    
        then D
    is_>=_than  
    [b, (x
    `2 )] by 
    A19,
    Th34;
    
        then x
    >=  
    [b, (x
    `2 )] by 
    A16;
    
        hence thesis by
    A17,
    Th11;
    
      end;
    
      hence
    ex_inf_of (( 
    proj1 D),S1) by 
    A18,
    YELLOW_0: 16;
    
      for b be
    Element of S2 st ( 
    proj2 D) 
    is_>=_than b holds (x 
    `2 ) 
    >= b 
    
      proof
    
        let b be
    Element of S2; 
    
        assume (
    proj2 D) 
    is_>=_than b; 
    
        then D
    is_>=_than  
    [(x
    `1 ), b] by 
    A18,
    Th34;
    
        then x
    >=  
    [(x
    `1 ), b] by 
    A16;
    
        hence thesis by
    A17,
    Th11;
    
      end;
    
      hence thesis by
    A19,
    YELLOW_0: 16;
    
    end;
    
    theorem :: 
    
    YELLOW_3:43
    
    
    
    
    
    Th43: for S1,S2 be 
    antisymmetric non 
    empty  
    RelStr holds for D1 be non 
    empty  
    Subset of S1, D2 be non 
    empty  
    Subset of S2 st 
    ex_sup_of (D1,S1) & 
    ex_sup_of (D2,S2) holds ( 
    sup  
    [:D1, D2:])
    =  
    [(
    sup D1), ( 
    sup D2)] 
    
    proof
    
      let S1,S2 be
    antisymmetric non 
    empty  
    RelStr, D1 be non 
    empty  
    Subset of S1, D2 be non 
    empty  
    Subset of S2 such that 
    
      
    
    A1: 
    ex_sup_of (D1,S1) & 
    ex_sup_of (D2,S2); 
    
      set s = (
    sup  
    [:D1, D2:]);
    
      s is
    Element of 
    [:the 
    carrier of S1, the 
    carrier of S2:] by 
    Def2;
    
      then
    
      consider s1,s2 be
    object such that 
    
      
    
    A2: s1 
    in the 
    carrier of S1 and 
    
      
    
    A3: s2 
    in the 
    carrier of S2 and 
    
      
    
    A4: s 
    =  
    [s1, s2] by
    ZFMISC_1:def 2;
    
      reconsider s2 as
    Element of S2 by 
    A3;
    
      reconsider s1 as
    Element of S1 by 
    A2;
    
      
    
      
    
    A5: 
    ex_sup_of ( 
    [:D1, D2:],
    [:S1, S2:]) by
    A1,
    Th39;
    
      then
    
      
    
    A6: 
    [s1, s2]
    is_>=_than  
    [:D1, D2:] by
    A4,
    YELLOW_0: 30;
    
      then
    
      
    
    A7: s1 
    is_>=_than D1 by 
    Th29;
    
      
    
      
    
    A8: for b be 
    Element of 
    [:S1, S2:] st b
    is_>=_than  
    [:D1, D2:] holds
    [s1, s2]
    <= b by 
    A4,
    A5,
    YELLOW_0: 30;
    
      then for b be
    Element of S1 st b 
    is_>=_than D1 holds s1 
    <= b by 
    A1,
    Th35;
    
      then
    
      
    
    A9: s1 
    = ( 
    sup D1) by 
    A7,
    YELLOW_0: 30;
    
      
    
      
    
    A10: s2 
    is_>=_than D2 by 
    A6,
    Th29;
    
      for b be
    Element of S2 st b 
    is_>=_than D2 holds s2 
    <= b by 
    A1,
    A8,
    Th35;
    
      hence thesis by
    A4,
    A9,
    A10,
    YELLOW_0: 30;
    
    end;
    
    theorem :: 
    
    YELLOW_3:44
    
    
    
    
    
    Th44: for S1,S2 be 
    antisymmetric non 
    empty  
    RelStr holds for D1 be non 
    empty  
    Subset of S1, D2 be non 
    empty  
    Subset of S2 st 
    ex_inf_of (D1,S1) & 
    ex_inf_of (D2,S2) holds ( 
    inf  
    [:D1, D2:])
    =  
    [(
    inf D1), ( 
    inf D2)] 
    
    proof
    
      let S1,S2 be
    antisymmetric non 
    empty  
    RelStr, D1 be non 
    empty  
    Subset of S1, D2 be non 
    empty  
    Subset of S2 such that 
    
      
    
    A1: 
    ex_inf_of (D1,S1) & 
    ex_inf_of (D2,S2); 
    
      set s = (
    inf  
    [:D1, D2:]);
    
      s is
    Element of 
    [:the 
    carrier of S1, the 
    carrier of S2:] by 
    Def2;
    
      then
    
      consider s1,s2 be
    object such that 
    
      
    
    A2: s1 
    in the 
    carrier of S1 and 
    
      
    
    A3: s2 
    in the 
    carrier of S2 and 
    
      
    
    A4: s 
    =  
    [s1, s2] by
    ZFMISC_1:def 2;
    
      reconsider s2 as
    Element of S2 by 
    A3;
    
      reconsider s1 as
    Element of S1 by 
    A2;
    
      
    
      
    
    A5: 
    ex_inf_of ( 
    [:D1, D2:],
    [:S1, S2:]) by
    A1,
    Th40;
    
      then
    
      
    
    A6: 
    [s1, s2]
    is_<=_than  
    [:D1, D2:] by
    A4,
    YELLOW_0: 31;
    
      then
    
      
    
    A7: s1 
    is_<=_than D1 by 
    Th32;
    
      
    
      
    
    A8: for b be 
    Element of 
    [:S1, S2:] st b
    is_<=_than  
    [:D1, D2:] holds
    [s1, s2]
    >= b by 
    A4,
    A5,
    YELLOW_0: 31;
    
      then for b be
    Element of S1 st b 
    is_<=_than D1 holds s1 
    >= b by 
    A1,
    Th36;
    
      then
    
      
    
    A9: s1 
    = ( 
    inf D1) by 
    A7,
    YELLOW_0: 31;
    
      
    
      
    
    A10: s2 
    is_<=_than D2 by 
    A6,
    Th32;
    
      for b be
    Element of S2 st b 
    is_<=_than D2 holds s2 
    >= b by 
    A1,
    A8,
    Th36;
    
      hence thesis by
    A4,
    A9,
    A10,
    YELLOW_0: 31;
    
    end;
    
    registration
    
      let X,Y be
    complete
    antisymmetric non 
    empty  
    RelStr;
    
      cluster 
    [:X, Y:] ->
    complete;
    
      coherence
    
      proof
    
        set IT =
    [:X, Y:];
    
        for D be
    Subset of IT holds 
    ex_sup_of (D,IT) 
    
        proof
    
          let D be
    Subset of IT; 
    
          
    ex_sup_of (( 
    proj1 D),X) & 
    ex_sup_of (( 
    proj2 D),Y) by 
    YELLOW_0: 17;
    
          hence thesis by
    Th41;
    
        end;
    
        hence thesis by
    YELLOW_0: 53;
    
      end;
    
    end
    
    theorem :: 
    
    YELLOW_3:45
    
    for X,Y be non
    empty
    lower-bounded
    antisymmetric  
    RelStr st 
    [:X, Y:] is
    complete holds X is 
    complete & Y is 
    complete
    
    proof
    
      let X,Y be non
    empty
    lower-bounded
    antisymmetric  
    RelStr such that 
    
      
    
    A1: 
    [:X, Y:] is
    complete;
    
      for A be
    Subset of X holds 
    ex_sup_of (A,X) 
    
      proof
    
        let A be
    Subset of X; 
    
        per cases ;
    
          suppose
    
          
    
    A2: A is non 
    empty;
    
          set B = the non
    empty  
    Subset of Y; 
    
          
    ex_sup_of ( 
    [:A, B:],
    [:X, Y:]) by
    A1,
    YELLOW_0: 17;
    
          hence thesis by
    A2,
    Th39;
    
        end;
    
          suppose A is
    empty;
    
          hence thesis by
    YELLOW_0: 42;
    
        end;
    
      end;
    
      hence X is
    complete by 
    YELLOW_0: 53;
    
      for B be
    Subset of Y holds 
    ex_sup_of (B,Y) 
    
      proof
    
        let B be
    Subset of Y; 
    
        per cases ;
    
          suppose
    
          
    
    A3: B is non 
    empty;
    
          set A = the non
    empty  
    Subset of X; 
    
          
    ex_sup_of ( 
    [:A, B:],
    [:X, Y:]) by
    A1,
    YELLOW_0: 17;
    
          hence thesis by
    A3,
    Th39;
    
        end;
    
          suppose B is
    empty;
    
          hence thesis by
    YELLOW_0: 42;
    
        end;
    
      end;
    
      hence thesis by
    YELLOW_0: 53;
    
    end;
    
    theorem :: 
    
    YELLOW_3:46
    
    for L1,L2 be
    antisymmetric non 
    empty  
    RelStr holds for D be non 
    empty  
    Subset of 
    [:L1, L2:] st
    [:L1, L2:] is
    complete or 
    ex_sup_of (D, 
    [:L1, L2:]) holds (
    sup D) 
    =  
    [(
    sup ( 
    proj1 D)), ( 
    sup ( 
    proj2 D))] 
    
    proof
    
      let L1,L2 be
    antisymmetric non 
    empty  
    RelStr, D be non 
    empty  
    Subset of 
    [:L1, L2:];
    
      reconsider C1 = the
    carrier of L1, C2 = the 
    carrier of L2 as non 
    empty  
    set;
    
      the
    carrier of 
    [:L1, L2:]
    =  
    [:C1, C2:] by
    Def2;
    
      then
    
      consider d1,d2 be
    object such that 
    
      
    
    A1: d1 
    in C1 and 
    
      
    
    A2: d2 
    in C2 and 
    
      
    
    A3: ( 
    sup D) 
    =  
    [d1, d2] by
    ZFMISC_1:def 2;
    
      reconsider d1 as
    Element of L1 by 
    A1;
    
      reconsider D9 = D as non
    empty  
    Subset of 
    [:C1, C2:] by
    Def2;
    
      (
    proj1 D9) is non 
    empty;
    
      then
    
      reconsider D1 = (
    proj1 D) as non 
    empty  
    Subset of L1; 
    
      (
    proj2 D9) is non 
    empty;
    
      then
    
      reconsider D2 = (
    proj2 D) as non 
    empty  
    Subset of L2; 
    
      
    
      
    
    A4: D9 
    c=  
    [:D1, D2:] by
    Th1;
    
      reconsider d2 as
    Element of L2 by 
    A2;
    
      assume
    [:L1, L2:] is
    complete or 
    ex_sup_of (D, 
    [:L1, L2:]);
    
      then
    
      
    
    A5: 
    ex_sup_of (D, 
    [:L1, L2:]) by
    YELLOW_0: 17;
    
      then
    
      
    
    A6: 
    ex_sup_of (D2,L2) by 
    Th41;
    
      
    
      
    
    A7: 
    ex_sup_of (D1,L1) by 
    A5,
    Th41;
    
      then
    ex_sup_of ( 
    [:D1, D2:],
    [:L1, L2:]) by
    A6,
    Th39;
    
      then (
    sup D) 
    <= ( 
    sup  
    [:D1, D2:]) by
    A5,
    A4,
    YELLOW_0: 34;
    
      then
    
      
    
    A8: ( 
    sup D) 
    <=  
    [(
    sup ( 
    proj1 D)), ( 
    sup ( 
    proj2 D))] by 
    A7,
    A6,
    Th43;
    
      D2
    is_<=_than d2 
    
      proof
    
        let b be
    Element of L2; 
    
        assume b
    in D2; 
    
        then
    
        consider x be
    object such that 
    
        
    
    A9: 
    [x, b]
    in D by 
    XTUPLE_0:def 13;
    
        reconsider x as
    Element of D1 by 
    A9,
    XTUPLE_0:def 12;
    
        reconsider x as
    Element of L1; 
    
        D
    is_<=_than  
    [d1, d2] by
    A5,
    A3,
    YELLOW_0:def 9;
    
        then
    [x, b]
    <=  
    [d1, d2] by
    A9;
    
        hence thesis by
    Th11;
    
      end;
    
      then
    
      
    
    A10: ( 
    sup D2) 
    <= d2 by 
    A6,
    YELLOW_0:def 9;
    
      D1
    is_<=_than d1 
    
      proof
    
        let b be
    Element of L1; 
    
        assume b
    in D1; 
    
        then
    
        consider x be
    object such that 
    
        
    
    A11: 
    [b, x]
    in D by 
    XTUPLE_0:def 12;
    
        reconsider x as
    Element of D2 by 
    A11,
    XTUPLE_0:def 13;
    
        reconsider x as
    Element of L2; 
    
        D
    is_<=_than  
    [d1, d2] by
    A5,
    A3,
    YELLOW_0:def 9;
    
        then
    [b, x]
    <=  
    [d1, d2] by
    A11;
    
        hence thesis by
    Th11;
    
      end;
    
      then (
    sup D1) 
    <= d1 by 
    A7,
    YELLOW_0:def 9;
    
      then
    [(
    sup D1), ( 
    sup D2)] 
    <= ( 
    sup D) by 
    A3,
    A10,
    Th11;
    
      hence thesis by
    A8,
    ORDERS_2: 2;
    
    end;
    
    theorem :: 
    
    YELLOW_3:47
    
    for L1,L2 be
    antisymmetric non 
    empty  
    RelStr holds for D be non 
    empty  
    Subset of 
    [:L1, L2:] st
    [:L1, L2:] is
    complete or 
    ex_inf_of (D, 
    [:L1, L2:]) holds (
    inf D) 
    =  
    [(
    inf ( 
    proj1 D)), ( 
    inf ( 
    proj2 D))] 
    
    proof
    
      let L1,L2 be
    antisymmetric non 
    empty  
    RelStr, D be non 
    empty  
    Subset of 
    [:L1, L2:];
    
      reconsider C1 = the
    carrier of L1, C2 = the 
    carrier of L2 as non 
    empty  
    set;
    
      the
    carrier of 
    [:L1, L2:]
    =  
    [:C1, C2:] by
    Def2;
    
      then
    
      consider d1,d2 be
    object such that 
    
      
    
    A1: d1 
    in C1 and 
    
      
    
    A2: d2 
    in C2 and 
    
      
    
    A3: ( 
    inf D) 
    =  
    [d1, d2] by
    ZFMISC_1:def 2;
    
      reconsider d1 as
    Element of L1 by 
    A1;
    
      reconsider D9 = D as non
    empty  
    Subset of 
    [:C1, C2:] by
    Def2;
    
      (
    proj1 D9) is non 
    empty;
    
      then
    
      reconsider D1 = (
    proj1 D) as non 
    empty  
    Subset of L1; 
    
      (
    proj2 D9) is non 
    empty;
    
      then
    
      reconsider D2 = (
    proj2 D) as non 
    empty  
    Subset of L2; 
    
      
    
      
    
    A4: D9 
    c=  
    [:D1, D2:] by
    Th1;
    
      reconsider d2 as
    Element of L2 by 
    A2;
    
      assume
    [:L1, L2:] is
    complete or 
    ex_inf_of (D, 
    [:L1, L2:]);
    
      then
    
      
    
    A5: 
    ex_inf_of (D, 
    [:L1, L2:]) by
    YELLOW_0: 17;
    
      then
    
      
    
    A6: 
    ex_inf_of (D2,L2) by 
    Th42;
    
      
    
      
    
    A7: 
    ex_inf_of (D1,L1) by 
    A5,
    Th42;
    
      then
    ex_inf_of ( 
    [:D1, D2:],
    [:L1, L2:]) by
    A6,
    Th40;
    
      then (
    inf D) 
    >= ( 
    inf  
    [:D1, D2:]) by
    A5,
    A4,
    YELLOW_0: 35;
    
      then
    
      
    
    A8: ( 
    inf D) 
    >=  
    [(
    inf ( 
    proj1 D)), ( 
    inf ( 
    proj2 D))] by 
    A7,
    A6,
    Th44;
    
      D2
    is_>=_than d2 
    
      proof
    
        let b be
    Element of L2; 
    
        assume b
    in D2; 
    
        then
    
        consider x be
    object such that 
    
        
    
    A9: 
    [x, b]
    in D by 
    XTUPLE_0:def 13;
    
        reconsider x as
    Element of D1 by 
    A9,
    XTUPLE_0:def 12;
    
        reconsider x as
    Element of L1; 
    
        D
    is_>=_than  
    [d1, d2] by
    A5,
    A3,
    YELLOW_0:def 10;
    
        then
    [x, b]
    >=  
    [d1, d2] by
    A9;
    
        hence thesis by
    Th11;
    
      end;
    
      then
    
      
    
    A10: ( 
    inf D2) 
    >= d2 by 
    A6,
    YELLOW_0:def 10;
    
      D1
    is_>=_than d1 
    
      proof
    
        let b be
    Element of L1; 
    
        assume b
    in D1; 
    
        then
    
        consider x be
    object such that 
    
        
    
    A11: 
    [b, x]
    in D by 
    XTUPLE_0:def 12;
    
        reconsider x as
    Element of D2 by 
    A11,
    XTUPLE_0:def 13;
    
        reconsider x as
    Element of L2; 
    
        D
    is_>=_than  
    [d1, d2] by
    A5,
    A3,
    YELLOW_0:def 10;
    
        then
    [b, x]
    >=  
    [d1, d2] by
    A11;
    
        hence thesis by
    Th11;
    
      end;
    
      then (
    inf D1) 
    >= d1 by 
    A7,
    YELLOW_0:def 10;
    
      then
    [(
    inf D1), ( 
    inf D2)] 
    >= ( 
    inf D) by 
    A3,
    A10,
    Th11;
    
      hence thesis by
    A8,
    ORDERS_2: 2;
    
    end;
    
    theorem :: 
    
    YELLOW_3:48
    
    for S1,S2 be non
    empty
    reflexive  
    RelStr holds for D be non 
    empty
    directed  
    Subset of 
    [:S1, S2:] holds
    [:(
    proj1 D), ( 
    proj2 D):] 
    c= ( 
    downarrow D) 
    
    proof
    
      let S1,S2 be non
    empty
    reflexive  
    RelStr, D be non 
    empty
    directed  
    Subset of 
    [:S1, S2:];
    
      reconsider C1 = the
    carrier of S1, C2 = the 
    carrier of S2 as non 
    empty  
    set;
    
      let q be
    object;
    
      reconsider D9 = D as non
    empty  
    Subset of 
    [:C1, C2:] by
    Def2;
    
      set D1 = (
    proj1 D), D2 = ( 
    proj2 D); 
    
      
    
      
    
    A1: ( 
    downarrow D) 
    = { x where x be 
    Element of 
    [:S1, S2:] : ex y be
    Element of 
    [:S1, S2:] st x
    <= y & y 
    in D } by 
    WAYBEL_0: 14;
    
      
    
      
    
    A2: D9 
    c=  
    [:D1, D2:] by
    Th1;
    
      (
    proj2 D9) is non 
    empty;
    
      then
    
      reconsider D2 as non
    empty  
    Subset of S2; 
    
      (
    proj1 D9) is non 
    empty;
    
      then
    
      reconsider D1 as non
    empty  
    Subset of S1; 
    
      assume q
    in  
    [:(
    proj1 D), ( 
    proj2 D):]; 
    
      then
    
      consider d,e be
    object such that 
    
      
    
    A3: d 
    in D1 and 
    
      
    
    A4: e 
    in D2 and 
    
      
    
    A5: q 
    =  
    [d, e] by
    ZFMISC_1:def 2;
    
      consider y be
    object such that 
    
      
    
    A6: 
    [d, y]
    in D by 
    A3,
    XTUPLE_0:def 12;
    
      consider x be
    object such that 
    
      
    
    A7: 
    [x, e]
    in D by 
    A4,
    XTUPLE_0:def 13;
    
      reconsider y, e as
    Element of D2 by 
    A6,
    A7,
    XTUPLE_0:def 13;
    
      reconsider x, d as
    Element of D1 by 
    A6,
    A7,
    XTUPLE_0:def 12;
    
      consider z be
    Element of 
    [:S1, S2:] such that
    
      
    
    A8: z 
    in D and 
    
      
    
    A9: 
    [d, y]
    <= z & 
    [x, e]
    <= z by 
    A6,
    A7,
    WAYBEL_0:def 1;
    
      consider z1,z2 be
    object such that 
    
      
    
    A10: z1 
    in D1 and 
    
      
    
    A11: z2 
    in D2 and 
    
      
    
    A12: z 
    =  
    [z1, z2] by
    A2,
    A8,
    ZFMISC_1:def 2;
    
      reconsider z2 as
    Element of D2 by 
    A11;
    
      reconsider z1 as
    Element of D1 by 
    A10;
    
      d
    <= z1 & e 
    <= z2 by 
    A9,
    A10,
    A11,
    A12,
    Th11;
    
      then
    [d, e]
    <=  
    [z1, z2] by
    Th11;
    
      hence thesis by
    A5,
    A1,
    A8,
    A12;
    
    end;
    
    theorem :: 
    
    YELLOW_3:49
    
    for S1,S2 be non
    empty
    reflexive  
    RelStr holds for D be non 
    empty
    filtered  
    Subset of 
    [:S1, S2:] holds
    [:(
    proj1 D), ( 
    proj2 D):] 
    c= ( 
    uparrow D) 
    
    proof
    
      let S1,S2 be non
    empty
    reflexive  
    RelStr, D be non 
    empty
    filtered  
    Subset of 
    [:S1, S2:];
    
      reconsider C1 = the
    carrier of S1, C2 = the 
    carrier of S2 as non 
    empty  
    set;
    
      let q be
    object;
    
      reconsider D9 = D as non
    empty  
    Subset of 
    [:C1, C2:] by
    Def2;
    
      set D1 = (
    proj1 D), D2 = ( 
    proj2 D); 
    
      
    
      
    
    A1: ( 
    uparrow D) 
    = { x where x be 
    Element of 
    [:S1, S2:] : ex y be
    Element of 
    [:S1, S2:] st x
    >= y & y 
    in D } by 
    WAYBEL_0: 15;
    
      
    
      
    
    A2: D9 
    c=  
    [:D1, D2:] by
    Th1;
    
      (
    proj2 D9) is non 
    empty;
    
      then
    
      reconsider D2 as non
    empty  
    Subset of S2; 
    
      (
    proj1 D9) is non 
    empty;
    
      then
    
      reconsider D1 as non
    empty  
    Subset of S1; 
    
      assume q
    in  
    [:(
    proj1 D), ( 
    proj2 D):]; 
    
      then
    
      consider d,e be
    object such that 
    
      
    
    A3: d 
    in D1 and 
    
      
    
    A4: e 
    in D2 and 
    
      
    
    A5: q 
    =  
    [d, e] by
    ZFMISC_1:def 2;
    
      consider y be
    object such that 
    
      
    
    A6: 
    [d, y]
    in D by 
    A3,
    XTUPLE_0:def 12;
    
      consider x be
    object such that 
    
      
    
    A7: 
    [x, e]
    in D by 
    A4,
    XTUPLE_0:def 13;
    
      reconsider y, e as
    Element of D2 by 
    A6,
    A7,
    XTUPLE_0:def 13;
    
      reconsider x, d as
    Element of D1 by 
    A6,
    A7,
    XTUPLE_0:def 12;
    
      consider z be
    Element of 
    [:S1, S2:] such that
    
      
    
    A8: z 
    in D and 
    
      
    
    A9: 
    [d, y]
    >= z & 
    [x, e]
    >= z by 
    A6,
    A7,
    WAYBEL_0:def 2;
    
      consider z1,z2 be
    object such that 
    
      
    
    A10: z1 
    in D1 and 
    
      
    
    A11: z2 
    in D2 and 
    
      
    
    A12: z 
    =  
    [z1, z2] by
    A2,
    A8,
    ZFMISC_1:def 2;
    
      reconsider z2 as
    Element of D2 by 
    A11;
    
      reconsider z1 as
    Element of D1 by 
    A10;
    
      d
    >= z1 & e 
    >= z2 by 
    A9,
    A10,
    A11,
    A12,
    Th11;
    
      then
    [d, e]
    >=  
    [z1, z2] by
    Th11;
    
      hence thesis by
    A5,
    A1,
    A8,
    A12;
    
    end;
    
    scheme :: 
    
    YELLOW_3:sch6
    
    Kappa2DS { X,Y,Z() -> non
    empty  
    RelStr , F( 
    set, 
    set) ->
    set } : 
    
ex f be 
    Function of 
    [:X(), Y():], Z() st for x be
    Element of X(), y be 
    Element of Y() holds (f 
    . (x,y)) 
    = F(x,y) 
    
      provided
    
      
    
    A1: for x be 
    Element of X(), y be 
    Element of Y() holds F(x,y) is 
    Element of Z(); 
    
      
    
      
    
    A2: for x be 
    Element of X(), y be 
    Element of Y() holds F(x,y) 
    in the 
    carrier of Z() 
    
      proof
    
        let x be
    Element of X(), y be 
    Element of Y(); 
    
        reconsider x1 = x as
    Element of X(); 
    
        reconsider y1 = y as
    Element of Y(); 
    
        F(x1,y1) is
    Element of Z() by 
    A1;
    
        hence thesis;
    
      end;
    
      consider f be
    Function of 
    [:the 
    carrier of X(), the 
    carrier of Y():], the 
    carrier of Z() such that 
    
      
    
    A3: for x be 
    Element of X(), y be 
    Element of Y() holds (f 
    . (x,y)) 
    = F(x,y) from 
    FUNCT_7:sch 1(
    A2);
    
      the
    carrier of 
    [:X(), Y():]
    =  
    [:the 
    carrier of X(), the 
    carrier of Y():] by 
    Def2;
    
      then
    
      reconsider f as
    Function of 
    [:X(), Y():], Z();
    
      take f;
    
      thus thesis by
    A3;
    
    end;