let A be non empty set ; :: thesis: for L being lower-bounded LATTICE
for O being Ordinal
for d being BiFunction of A,L st d is symmetric holds
for q being QuadrSeq of d holds ConsecutiveDelta q,O is symmetric

let L be lower-bounded LATTICE; :: thesis: for O being Ordinal
for d being BiFunction of A,L st d is symmetric holds
for q being QuadrSeq of d holds ConsecutiveDelta q,O is symmetric

let O be Ordinal; :: thesis: for d being BiFunction of A,L st d is symmetric holds
for q being QuadrSeq of d holds ConsecutiveDelta q,O is symmetric

let d be BiFunction of A,L; :: thesis: ( d is symmetric implies for q being QuadrSeq of d holds ConsecutiveDelta q,O is symmetric )
assume A1: d is symmetric ; :: thesis: for q being QuadrSeq of d holds ConsecutiveDelta q,O is symmetric
let q be QuadrSeq of d; :: thesis: ConsecutiveDelta q,O is symmetric
defpred S1[ Ordinal] means ConsecutiveDelta q,$1 is symmetric ;
A2: for O1 being Ordinal st S1[O1] holds
S1[ succ O1]
proof
let O1 be Ordinal; :: thesis: ( S1[O1] implies S1[ succ O1] )
assume ConsecutiveDelta q,O1 is symmetric ; :: thesis: S1[ succ O1]
then A3: new_bi_fun (ConsecutiveDelta q,O1),(Quadr q,O1) is symmetric by Th19;
let x, y be Element of ConsecutiveSet A,(succ O1); :: according to LATTICE5:def 6 :: thesis: (ConsecutiveDelta q,(succ O1)) . x,y = (ConsecutiveDelta q,(succ O1)) . y,x
reconsider x9 = x, y9 = y as Element of new_set (ConsecutiveSet A,O1) by Th25;
A4: ConsecutiveDelta q,(succ O1) = new_bi_fun (BiFun (ConsecutiveDelta q,O1),(ConsecutiveSet A,O1),L),(Quadr q,O1) by Th30
.= new_bi_fun (ConsecutiveDelta q,O1),(Quadr q,O1) by Def16 ;
hence (ConsecutiveDelta q,(succ O1)) . x,y = (new_bi_fun (ConsecutiveDelta q,O1),(Quadr q,O1)) . y9,x9 by A3, Def6
.= (ConsecutiveDelta q,(succ O1)) . y,x by A4 ;
:: thesis: verum
end;
A5: for O2 being Ordinal st O2 <> {} & O2 is limit_ordinal & ( for O1 being Ordinal st O1 in O2 holds
S1[O1] ) holds
S1[O2]
proof
deffunc H1( Ordinal) -> BiFunction of (ConsecutiveSet A,$1),L = ConsecutiveDelta q,$1;
let O2 be Ordinal; :: thesis: ( O2 <> {} & O2 is limit_ordinal & ( for O1 being Ordinal st O1 in O2 holds
S1[O1] ) implies S1[O2] )

assume that
A6: ( O2 <> {} & O2 is limit_ordinal ) and
A7: for O1 being Ordinal st O1 in O2 holds
ConsecutiveDelta q,O1 is symmetric ; :: thesis: S1[O2]
set CS = ConsecutiveSet A,O2;
consider Ls being T-Sequence such that
A8: ( dom Ls = O2 & ( for O1 being Ordinal st O1 in O2 holds
Ls . O1 = H1(O1) ) ) from ORDINAL2:sch 2();
ConsecutiveDelta q,O2 = union (rng Ls) by A6, A8, Th31;
then reconsider f = union (rng Ls) as BiFunction of (ConsecutiveSet A,O2),L ;
deffunc H2( Ordinal) -> set = ConsecutiveSet A,$1;
consider Ts being T-Sequence such that
A9: ( dom Ts = O2 & ( for O1 being Ordinal st O1 in O2 holds
Ts . O1 = H2(O1) ) ) from ORDINAL2:sch 2();
A10: ConsecutiveSet A,O2 = union (rng Ts) by A6, A9, Th26;
f is symmetric
proof
let x, y be Element of ConsecutiveSet A,O2; :: according to LATTICE5:def 6 :: thesis: f . x,y = f . y,x
consider x1 being set such that
A11: x in x1 and
A12: x1 in rng Ts by A10, TARSKI:def 4;
consider o1 being set such that
A13: o1 in dom Ts and
A14: x1 = Ts . o1 by A12, FUNCT_1:def 5;
consider y1 being set such that
A15: y in y1 and
A16: y1 in rng Ts by A10, TARSKI:def 4;
consider o2 being set such that
A17: o2 in dom Ts and
A18: y1 = Ts . o2 by A16, FUNCT_1:def 5;
reconsider o1 = o1, o2 = o2 as Ordinal by A13, A17;
A19: x in ConsecutiveSet A,o1 by A9, A11, A13, A14;
A20: Ls . o1 = ConsecutiveDelta q,o1 by A8, A9, A13;
then reconsider h1 = Ls . o1 as BiFunction of (ConsecutiveSet A,o1),L ;
A21: h1 is symmetric
proof
let x, y be Element of ConsecutiveSet A,o1; :: according to LATTICE5:def 6 :: thesis: h1 . x,y = h1 . y,x
A22: ConsecutiveDelta q,o1 is symmetric by A7, A9, A13;
thus h1 . x,y = (ConsecutiveDelta q,o1) . x,y by A8, A9, A13
.= (ConsecutiveDelta q,o1) . y,x by A22, Def6
.= h1 . y,x by A8, A9, A13 ; :: thesis: verum
end;
A23: dom h1 = [:(ConsecutiveSet A,o1),(ConsecutiveSet A,o1):] by FUNCT_2:def 1;
A24: y in ConsecutiveSet A,o2 by A9, A15, A17, A18;
A25: Ls . o2 = ConsecutiveDelta q,o2 by A8, A9, A17;
then reconsider h2 = Ls . o2 as BiFunction of (ConsecutiveSet A,o2),L ;
A26: h2 is symmetric
proof
let x, y be Element of ConsecutiveSet A,o2; :: according to LATTICE5:def 6 :: thesis: h2 . x,y = h2 . y,x
A27: ConsecutiveDelta q,o2 is symmetric by A7, A9, A17;
thus h2 . x,y = (ConsecutiveDelta q,o2) . x,y by A8, A9, A17
.= (ConsecutiveDelta q,o2) . y,x by A27, Def6
.= h2 . y,x by A8, A9, A17 ; :: thesis: verum
end;
A28: dom h2 = [:(ConsecutiveSet A,o2),(ConsecutiveSet A,o2):] by FUNCT_2:def 1;
per cases ( o1 c= o2 or o2 c= o1 ) ;
suppose o1 c= o2 ; :: thesis: f . x,y = f . y,x
then A29: ConsecutiveSet A,o1 c= ConsecutiveSet A,o2 by Th32;
then A30: [y,x] in dom h2 by A19, A24, A28, ZFMISC_1:106;
ConsecutiveDelta q,o2 in rng Ls by A8, A9, A17, A25, FUNCT_1:def 5;
then A31: h2 c= f by A25, ZFMISC_1:92;
reconsider x9 = x, y9 = y as Element of ConsecutiveSet A,o2 by A9, A15, A17, A18, A19, A29;
[x,y] in dom h2 by A19, A24, A28, A29, ZFMISC_1:106;
hence f . x,y = h2 . x9,y9 by A31, GRFUNC_1:8
.= h2 . y9,x9 by A26, Def6
.= f . y,x by A31, A30, GRFUNC_1:8 ;
:: thesis: verum
end;
suppose o2 c= o1 ; :: thesis: f . x,y = f . y,x
then A32: ConsecutiveSet A,o2 c= ConsecutiveSet A,o1 by Th32;
then A33: [y,x] in dom h1 by A19, A24, A23, ZFMISC_1:106;
ConsecutiveDelta q,o1 in rng Ls by A8, A9, A13, A20, FUNCT_1:def 5;
then A34: h1 c= f by A20, ZFMISC_1:92;
reconsider x9 = x, y9 = y as Element of ConsecutiveSet A,o1 by A9, A11, A13, A14, A24, A32;
[x,y] in dom h1 by A19, A24, A23, A32, ZFMISC_1:106;
hence f . x,y = h1 . x9,y9 by A34, GRFUNC_1:8
.= h1 . y9,x9 by A21, Def6
.= f . y,x by A34, A33, GRFUNC_1:8 ;
:: thesis: verum
end;
end;
end;
hence S1[O2] by A6, A8, Th31; :: thesis: verum
end;
A35: S1[ {} ]
proof
let x, y be Element of ConsecutiveSet A,{} ; :: according to LATTICE5:def 6 :: thesis: (ConsecutiveDelta q,{} ) . x,y = (ConsecutiveDelta q,{} ) . y,x
reconsider x9 = x, y9 = y as Element of A by Th24;
thus (ConsecutiveDelta q,{} ) . x,y = d . x9,y9 by Th29
.= d . y9,x9 by A1, Def6
.= (ConsecutiveDelta q,{} ) . y,x by Th29 ; :: thesis: verum
end;
for O being Ordinal holds S1[O] from ORDINAL2:sch 1(A35, A2, A5);
hence ConsecutiveDelta q,O is symmetric ; :: thesis: verum