deffunc H1( Ordinal) -> Subset of [:(Day $1),(Day $1):] = Triangle $1;
deffunc H2( object , Function-yielding c=-monotone Sequence) -> object = [( { ((((union (rng $2)) . [xL,(R_ $1)]) +' ((union (rng $2)) . [(L_ $1),yL])) +' (-' ((union (rng $2)) . [xL,yL]))) where xL is Element of L_ (L_ $1), yL is Element of L_ (R_ $1) : ( xL in L_ (L_ $1) & yL in L_ (R_ $1) ) } \/ { ((((union (rng $2)) . [xR,(R_ $1)]) +' ((union (rng $2)) . [(L_ $1),yR])) +' (-' ((union (rng $2)) . [xR,yR]))) where xR is Element of R_ (L_ $1), yR is Element of R_ (R_ $1) : ( xR in R_ (L_ $1) & yR in R_ (R_ $1) ) } ),( { ((((union (rng $2)) . [xL,(R_ $1)]) +' ((union (rng $2)) . [(L_ $1),yR])) +' (-' ((union (rng $2)) . [xL,yR]))) where xL is Element of L_ (L_ $1), yR is Element of R_ (R_ $1) : ( xL in L_ (L_ $1) & yR in R_ (R_ $1) ) } \/ { ((((union (rng $2)) . [xR,(R_ $1)]) +' ((union (rng $2)) . [(L_ $1),yL])) +' (-' ((union (rng $2)) . [xR,yL]))) where xR is Element of R_ (L_ $1), yL is Element of L_ (R_ $1) : ( xR in R_ (L_ $1) & yL in L_ (R_ $1) ) } )];
A1: for A, B being Ordinal st A c= B holds
H1(A) c= H1(B) by Th25;
A2: for S being Function-yielding c=-monotone Sequence st ( for A being Ordinal st A in dom S holds
dom (S . A) = H1(A) ) holds
for A being Ordinal
for x being object st x in dom (S . A) holds
H2(x,S | A) = H2(x,S)
proof
let S be Function-yielding c=-monotone Sequence; :: thesis: ( ( for A being Ordinal st A in dom S holds
dom (S . A) = H1(A) ) implies for A being Ordinal
for x being object st x in dom (S . A) holds
H2(x,S | A) = H2(x,S) )

assume A3: for A being Ordinal st A in dom S holds
dom (S . A) = H1(A) ; :: thesis: for A being Ordinal
for x being object st x in dom (S . A) holds
H2(x,S | A) = H2(x,S)

let A be Ordinal; :: thesis: for x being object st x in dom (S . A) holds
H2(x,S | A) = H2(x,S)

let a be object ; :: thesis: ( a in dom (S . A) implies H2(a,S | A) = H2(a,S) )
assume A4: a in dom (S . A) ; :: thesis: H2(a,S | A) = H2(a,S)
S . A <> {} by A4;
then A5: A in dom S by FUNCT_1:def 2;
then A6: dom (S . A) = H1(A) by A3;
then consider x, y being object such that
A7: ( x in Day A & y in Day A & a = [x,y] ) by A4, ZFMISC_1:def 2;
reconsider x = x, y = y as Surreal by A7;
A8: (born x) (+) (born y) c= A by A7, A6, A4, Def5;
A9: for X, Y being surreal-membered set st X c= (L_ x) \/ (R_ x) & Y c= (L_ y) \/ (R_ y) holds
{ ((((union (rng (S | A))) . [xL,y]) +' ((union (rng (S | A))) . [x,yL])) +' (-' ((union (rng (S | A))) . [xL,yL]))) where xL is Element of X, yL is Element of Y : ( xL in X & yL in Y ) } = { ((((union (rng S)) . [xL,y]) +' ((union (rng S)) . [x,yL])) +' (-' ((union (rng S)) . [xL,yL]))) where xL is Element of X, yL is Element of Y : ( xL in X & yL in Y ) }
proof
let X, Y be surreal-membered set ; :: thesis: ( X c= (L_ x) \/ (R_ x) & Y c= (L_ y) \/ (R_ y) implies { ((((union (rng (S | A))) . [xL,y]) +' ((union (rng (S | A))) . [x,yL])) +' (-' ((union (rng (S | A))) . [xL,yL]))) where xL is Element of X, yL is Element of Y : ( xL in X & yL in Y ) } = { ((((union (rng S)) . [xL,y]) +' ((union (rng S)) . [x,yL])) +' (-' ((union (rng S)) . [xL,yL]))) where xL is Element of X, yL is Element of Y : ( xL in X & yL in Y ) } )
assume A10: ( X c= (L_ x) \/ (R_ x) & Y c= (L_ y) \/ (R_ y) ) ; :: thesis: { ((((union (rng (S | A))) . [xL,y]) +' ((union (rng (S | A))) . [x,yL])) +' (-' ((union (rng (S | A))) . [xL,yL]))) where xL is Element of X, yL is Element of Y : ( xL in X & yL in Y ) } = { ((((union (rng S)) . [xL,y]) +' ((union (rng S)) . [x,yL])) +' (-' ((union (rng S)) . [xL,yL]))) where xL is Element of X, yL is Element of Y : ( xL in X & yL in Y ) }
thus { ((((union (rng (S | A))) . [xL,y]) +' ((union (rng (S | A))) . [x,yL])) +' (-' ((union (rng (S | A))) . [xL,yL]))) where xL is Element of X, yL is Element of Y : ( xL in X & yL in Y ) } c= { ((((union (rng S)) . [xL,y]) +' ((union (rng S)) . [x,yL])) +' (-' ((union (rng S)) . [xL,yL]))) where xL is Element of X, yL is Element of Y : ( xL in X & yL in Y ) } :: according to XBOOLE_0:def 10 :: thesis: { ((((union (rng S)) . [xL,y]) +' ((union (rng S)) . [x,yL])) +' (-' ((union (rng S)) . [xL,yL]))) where xL is Element of X, yL is Element of Y : ( xL in X & yL in Y ) } c= { ((((union (rng (S | A))) . [xL,y]) +' ((union (rng (S | A))) . [x,yL])) +' (-' ((union (rng (S | A))) . [xL,yL]))) where xL is Element of X, yL is Element of Y : ( xL in X & yL in Y ) }
proof
let z be object ; :: according to TARSKI:def 3 :: thesis: ( not z in { ((((union (rng (S | A))) . [xL,y]) +' ((union (rng (S | A))) . [x,yL])) +' (-' ((union (rng (S | A))) . [xL,yL]))) where xL is Element of X, yL is Element of Y : ( xL in X & yL in Y ) } or z in { ((((union (rng S)) . [xL,y]) +' ((union (rng S)) . [x,yL])) +' (-' ((union (rng S)) . [xL,yL]))) where xL is Element of X, yL is Element of Y : ( xL in X & yL in Y ) } )
assume z in { ((((union (rng (S | A))) . [xL,y]) +' ((union (rng (S | A))) . [x,yL])) +' (-' ((union (rng (S | A))) . [xL,yL]))) where xL is Element of X, yL is Element of Y : ( xL in X & yL in Y ) } ; :: thesis: z in { ((((union (rng S)) . [xL,y]) +' ((union (rng S)) . [x,yL])) +' (-' ((union (rng S)) . [xL,yL]))) where xL is Element of X, yL is Element of Y : ( xL in X & yL in Y ) }
then consider xL being Element of X, yL being Element of Y such that
A11: ( z = (((union (rng (S | A))) . [xL,y]) +' ((union (rng (S | A))) . [x,yL])) +' (-' ((union (rng (S | A))) . [xL,yL])) & xL in X & yL in Y ) ;
reconsider xxL = xL, yyL = yL as Surreal by SURREAL0:def 16, A11;
set Lx = (born xxL) (+) (born y);
A12: (born xxL) (+) (born y) in (born x) (+) (born y) by ORDINAL7:94, SURREALO:1, A10, A11;
then A13: dom (S . ((born xxL) (+) (born y))) = H1((born xxL) (+) (born y)) by A8, A3, A5, ORDINAL1:10;
[xL,y] in H1((born xxL) (+) (born y)) by Def5;
then A14: (union (rng (S | A))) . [xL,y] = (union (rng S)) . [xL,y] by Th6, A13, A12, A8;
set Ly = (born x) (+) (born yyL);
A15: (born x) (+) (born yyL) in (born x) (+) (born y) by A10, A11, ORDINAL7:94, SURREALO:1;
then A16: dom (S . ((born x) (+) (born yyL))) = H1((born x) (+) (born yyL)) by A8, A3, A5, ORDINAL1:10;
[x,yL] in H1((born x) (+) (born yyL)) by Def5;
then A17: (union (rng (S | A))) . [x,yL] = (union (rng S)) . [x,yL] by Th6, A16, A15, A8;
set Lxy = (born xxL) (+) (born yyL);
A18: (born xxL) (+) (born yyL) in (born x) (+) (born yyL) by A10, A11, ORDINAL7:94, SURREALO:1;
then (born xxL) (+) (born yyL) in (born x) (+) (born y) by A15, ORDINAL1:10;
then A19: dom (S . ((born xxL) (+) (born yyL))) = H1((born xxL) (+) (born yyL)) by A8, A3, A5, ORDINAL1:10;
[xL,yL] in H1((born xxL) (+) (born yyL)) by Def5;
then (union (rng (S | A))) . [xL,yL] = (union (rng S)) . [xL,yL] by Th6, A19, A18, A8, A15, ORDINAL1:10;
hence z in { ((((union (rng S)) . [xL,y]) +' ((union (rng S)) . [x,yL])) +' (-' ((union (rng S)) . [xL,yL]))) where xL is Element of X, yL is Element of Y : ( xL in X & yL in Y ) } by A14, A17, A11; :: thesis: verum
end;
let z be object ; :: according to TARSKI:def 3 :: thesis: ( not z in { ((((union (rng S)) . [xL,y]) +' ((union (rng S)) . [x,yL])) +' (-' ((union (rng S)) . [xL,yL]))) where xL is Element of X, yL is Element of Y : ( xL in X & yL in Y ) } or z in { ((((union (rng (S | A))) . [xL,y]) +' ((union (rng (S | A))) . [x,yL])) +' (-' ((union (rng (S | A))) . [xL,yL]))) where xL is Element of X, yL is Element of Y : ( xL in X & yL in Y ) } )
assume z in { ((((union (rng S)) . [xL,y]) +' ((union (rng S)) . [x,yL])) +' (-' ((union (rng S)) . [xL,yL]))) where xL is Element of X, yL is Element of Y : ( xL in X & yL in Y ) } ; :: thesis: z in { ((((union (rng (S | A))) . [xL,y]) +' ((union (rng (S | A))) . [x,yL])) +' (-' ((union (rng (S | A))) . [xL,yL]))) where xL is Element of X, yL is Element of Y : ( xL in X & yL in Y ) }
then consider xL being Element of X, yL being Element of Y such that
A20: ( z = (((union (rng S)) . [xL,y]) +' ((union (rng S)) . [x,yL])) +' (-' ((union (rng S)) . [xL,yL])) & xL in X & yL in Y ) ;
reconsider xxL = xL, yyL = yL as Surreal by SURREAL0:def 16, A20;
set Lx = (born xxL) (+) (born y);
A21: (born xxL) (+) (born y) in (born x) (+) (born y) by A10, A20, ORDINAL7:94, SURREALO:1;
then A22: dom (S . ((born xxL) (+) (born y))) = H1((born xxL) (+) (born y)) by A8, A3, A5, ORDINAL1:10;
[xL,y] in H1((born xxL) (+) (born y)) by Def5;
then A23: (union (rng (S | A))) . [xL,y] = (union (rng S)) . [xL,y] by Th6, A22, A21, A8;
set Ly = (born x) (+) (born yyL);
A24: (born x) (+) (born yyL) in (born x) (+) (born y) by A10, A20, ORDINAL7:94, SURREALO:1;
then A25: dom (S . ((born x) (+) (born yyL))) = H1((born x) (+) (born yyL)) by A8, A3, A5, ORDINAL1:10;
[x,yL] in H1((born x) (+) (born yyL)) by Def5;
then A26: (union (rng (S | A))) . [x,yL] = (union (rng S)) . [x,yL] by Th6, A25, A24, A8;
set Lxy = (born xxL) (+) (born yyL);
A27: (born xxL) (+) (born yyL) in (born x) (+) (born yyL) by A10, A20, ORDINAL7:94, SURREALO:1;
then (born xxL) (+) (born yyL) in (born x) (+) (born y) by A24, ORDINAL1:10;
then A28: dom (S . ((born xxL) (+) (born yyL))) = H1((born xxL) (+) (born yyL)) by A8, A3, A5, ORDINAL1:10;
[xL,yL] in H1((born xxL) (+) (born yyL)) by Def5;
then (union (rng (S | A))) . [xL,yL] = (union (rng S)) . [xL,yL] by Th6, A28, A27, A8, A24, ORDINAL1:10;
hence z in { ((((union (rng (S | A))) . [xL,y]) +' ((union (rng (S | A))) . [x,yL])) +' (-' ((union (rng (S | A))) . [xL,yL]))) where xL is Element of X, yL is Element of Y : ( xL in X & yL in Y ) } by A23, A26, A20; :: thesis: verum
end;
A29: ( L_ x c= (L_ x) \/ (R_ x) & R_ x c= (L_ x) \/ (R_ x) & L_ y c= (L_ y) \/ (R_ y) & R_ y c= (L_ y) \/ (R_ y) ) by XBOOLE_1:7;
then A30: { ((((union (rng (S | A))) . [xL,y]) +' ((union (rng (S | A))) . [x,yL])) +' (-' ((union (rng (S | A))) . [xL,yL]))) where xL is Element of L_ x, yL is Element of L_ y : ( xL in L_ x & yL in L_ y ) } = { ((((union (rng S)) . [xL,y]) +' ((union (rng S)) . [x,yL])) +' (-' ((union (rng S)) . [xL,yL]))) where xL is Element of L_ x, yL is Element of L_ y : ( xL in L_ x & yL in L_ y ) } by A9;
A31: { ((((union (rng (S | A))) . [xR,y]) +' ((union (rng (S | A))) . [x,yR])) +' (-' ((union (rng (S | A))) . [xR,yR]))) where xR is Element of R_ x, yR is Element of R_ y : ( xR in R_ x & yR in R_ y ) } = { ((((union (rng S)) . [xR,y]) +' ((union (rng S)) . [x,yR])) +' (-' ((union (rng S)) . [xR,yR]))) where xR is Element of R_ x, yR is Element of R_ y : ( xR in R_ x & yR in R_ y ) } by A29, A9;
{ ((((union (rng (S | A))) . [xL,y]) +' ((union (rng (S | A))) . [x,yR])) +' (-' ((union (rng (S | A))) . [xL,yR]))) where xL is Element of L_ x, yR is Element of R_ y : ( xL in L_ x & yR in R_ y ) } = { ((((union (rng S)) . [xL,y]) +' ((union (rng S)) . [x,yR])) +' (-' ((union (rng S)) . [xL,yR]))) where xL is Element of L_ x, yR is Element of R_ y : ( xL in L_ x & yR in R_ y ) } by A29, A9;
hence H2(a,S | A) = H2(a,S) by A7, A30, A31, A29, A9; :: thesis: verum
end;
consider S being Function-yielding c=-monotone Sequence such that
A32: dom S = succ A and
A33: for A1 being Ordinal st A1 in succ A holds
ex SA1 being ManySortedSet of H1(A1) st
( S . A1 = SA1 & ( for x being object st x in H1(A1) holds
SA1 . x = H2(x,S | A1) ) ) from SURREALR:sch 1(A2, A1);
consider SA being ManySortedSet of H1(A) such that
A34: S . A = SA and
for x being object st x in H1(A) holds
SA . x = H2(x,S | A) by A33, ORDINAL1:6;
take SA ; :: thesis: ex S being Function-yielding c=-monotone Sequence st
( dom S = succ A & SA = S . A & ( for B being Ordinal st B in succ A holds
ex SB being ManySortedSet of Triangle B st
( S . B = SB & ( for x being object st x in Triangle B holds
SB . x = [( { ((((union (rng (S | B))) . [xL,(R_ x)]) +' ((union (rng (S | B))) . [(L_ x),yL])) +' (-' ((union (rng (S | B))) . [xL,yL]))) where xL is Element of L_ (L_ x), yL is Element of L_ (R_ x) : ( xL in L_ (L_ x) & yL in L_ (R_ x) ) } \/ { ((((union (rng (S | B))) . [xR,(R_ x)]) +' ((union (rng (S | B))) . [(L_ x),yR])) +' (-' ((union (rng (S | B))) . [xR,yR]))) where xR is Element of R_ (L_ x), yR is Element of R_ (R_ x) : ( xR in R_ (L_ x) & yR in R_ (R_ x) ) } ),( { ((((union (rng (S | B))) . [xL,(R_ x)]) +' ((union (rng (S | B))) . [(L_ x),yR])) +' (-' ((union (rng (S | B))) . [xL,yR]))) where xL is Element of L_ (L_ x), yR is Element of R_ (R_ x) : ( xL in L_ (L_ x) & yR in R_ (R_ x) ) } \/ { ((((union (rng (S | B))) . [xR,(R_ x)]) +' ((union (rng (S | B))) . [(L_ x),yL])) +' (-' ((union (rng (S | B))) . [xR,yL]))) where xR is Element of R_ (L_ x), yL is Element of L_ (R_ x) : ( xR in R_ (L_ x) & yL in L_ (R_ x) ) } )] ) ) ) )

take S ; :: thesis: ( dom S = succ A & SA = S . A & ( for B being Ordinal st B in succ A holds
ex SB being ManySortedSet of Triangle B st
( S . B = SB & ( for x being object st x in Triangle B holds
SB . x = [( { ((((union (rng (S | B))) . [xL,(R_ x)]) +' ((union (rng (S | B))) . [(L_ x),yL])) +' (-' ((union (rng (S | B))) . [xL,yL]))) where xL is Element of L_ (L_ x), yL is Element of L_ (R_ x) : ( xL in L_ (L_ x) & yL in L_ (R_ x) ) } \/ { ((((union (rng (S | B))) . [xR,(R_ x)]) +' ((union (rng (S | B))) . [(L_ x),yR])) +' (-' ((union (rng (S | B))) . [xR,yR]))) where xR is Element of R_ (L_ x), yR is Element of R_ (R_ x) : ( xR in R_ (L_ x) & yR in R_ (R_ x) ) } ),( { ((((union (rng (S | B))) . [xL,(R_ x)]) +' ((union (rng (S | B))) . [(L_ x),yR])) +' (-' ((union (rng (S | B))) . [xL,yR]))) where xL is Element of L_ (L_ x), yR is Element of R_ (R_ x) : ( xL in L_ (L_ x) & yR in R_ (R_ x) ) } \/ { ((((union (rng (S | B))) . [xR,(R_ x)]) +' ((union (rng (S | B))) . [(L_ x),yL])) +' (-' ((union (rng (S | B))) . [xR,yL]))) where xR is Element of R_ (L_ x), yL is Element of L_ (R_ x) : ( xR in R_ (L_ x) & yL in L_ (R_ x) ) } )] ) ) ) )

thus ( dom S = succ A & SA = S . A & ( for B being Ordinal st B in succ A holds
ex SB being ManySortedSet of Triangle B st
( S . B = SB & ( for x being object st x in Triangle B holds
SB . x = [( { ((((union (rng (S | B))) . [xL,(R_ x)]) +' ((union (rng (S | B))) . [(L_ x),yL])) +' (-' ((union (rng (S | B))) . [xL,yL]))) where xL is Element of L_ (L_ x), yL is Element of L_ (R_ x) : ( xL in L_ (L_ x) & yL in L_ (R_ x) ) } \/ { ((((union (rng (S | B))) . [xR,(R_ x)]) +' ((union (rng (S | B))) . [(L_ x),yR])) +' (-' ((union (rng (S | B))) . [xR,yR]))) where xR is Element of R_ (L_ x), yR is Element of R_ (R_ x) : ( xR in R_ (L_ x) & yR in R_ (R_ x) ) } ),( { ((((union (rng (S | B))) . [xL,(R_ x)]) +' ((union (rng (S | B))) . [(L_ x),yR])) +' (-' ((union (rng (S | B))) . [xL,yR]))) where xL is Element of L_ (L_ x), yR is Element of R_ (R_ x) : ( xL in L_ (L_ x) & yR in R_ (R_ x) ) } \/ { ((((union (rng (S | B))) . [xR,(R_ x)]) +' ((union (rng (S | B))) . [(L_ x),yL])) +' (-' ((union (rng (S | B))) . [xR,yL]))) where xR is Element of R_ (L_ x), yL is Element of L_ (R_ x) : ( xR in R_ (L_ x) & yL in L_ (R_ x) ) } )] ) ) ) ) by A32, A34, A33; :: thesis: verum