let n be non empty Nat; for J being non empty non void Signature
for T being non-empty MSAlgebra over J
for X being empty-yielding GeneratorSet of T
for S1 being non empty non void b1 -extension n PC-correct QC-correct QCLangSignature over Union X
for x, y being Element of Union X
for x0, y0 being Element of Union (X extended_by ({}, the carrier of S1))
for L being non-empty Language of X extended_by ({}, the carrier of S1),S1
for G1 being QC-theory_with_equality of L
for A being Formula of L
for s being SortSymbol of S1 st L is subst-correct & x = x0 & x0 in X . s & y = y0 & y0 in X . s holds
(A \and (\not (A / (x0,y0)))) \imp (\not (x '=' (y,L))) in G1
let J be non empty non void Signature; for T being non-empty MSAlgebra over J
for X being empty-yielding GeneratorSet of T
for S1 being non empty non void J -extension n PC-correct QC-correct QCLangSignature over Union X
for x, y being Element of Union X
for x0, y0 being Element of Union (X extended_by ({}, the carrier of S1))
for L being non-empty Language of X extended_by ({}, the carrier of S1),S1
for G1 being QC-theory_with_equality of L
for A being Formula of L
for s being SortSymbol of S1 st L is subst-correct & x = x0 & x0 in X . s & y = y0 & y0 in X . s holds
(A \and (\not (A / (x0,y0)))) \imp (\not (x '=' (y,L))) in G1
let T be non-empty MSAlgebra over J; for X being empty-yielding GeneratorSet of T
for S1 being non empty non void J -extension n PC-correct QC-correct QCLangSignature over Union X
for x, y being Element of Union X
for x0, y0 being Element of Union (X extended_by ({}, the carrier of S1))
for L being non-empty Language of X extended_by ({}, the carrier of S1),S1
for G1 being QC-theory_with_equality of L
for A being Formula of L
for s being SortSymbol of S1 st L is subst-correct & x = x0 & x0 in X . s & y = y0 & y0 in X . s holds
(A \and (\not (A / (x0,y0)))) \imp (\not (x '=' (y,L))) in G1
let X be empty-yielding GeneratorSet of T; for S1 being non empty non void J -extension n PC-correct QC-correct QCLangSignature over Union X
for x, y being Element of Union X
for x0, y0 being Element of Union (X extended_by ({}, the carrier of S1))
for L being non-empty Language of X extended_by ({}, the carrier of S1),S1
for G1 being QC-theory_with_equality of L
for A being Formula of L
for s being SortSymbol of S1 st L is subst-correct & x = x0 & x0 in X . s & y = y0 & y0 in X . s holds
(A \and (\not (A / (x0,y0)))) \imp (\not (x '=' (y,L))) in G1
let S1 be non empty non void J -extension n PC-correct QC-correct QCLangSignature over Union X; for x, y being Element of Union X
for x0, y0 being Element of Union (X extended_by ({}, the carrier of S1))
for L being non-empty Language of X extended_by ({}, the carrier of S1),S1
for G1 being QC-theory_with_equality of L
for A being Formula of L
for s being SortSymbol of S1 st L is subst-correct & x = x0 & x0 in X . s & y = y0 & y0 in X . s holds
(A \and (\not (A / (x0,y0)))) \imp (\not (x '=' (y,L))) in G1
let x, y be Element of Union X; for x0, y0 being Element of Union (X extended_by ({}, the carrier of S1))
for L being non-empty Language of X extended_by ({}, the carrier of S1),S1
for G1 being QC-theory_with_equality of L
for A being Formula of L
for s being SortSymbol of S1 st L is subst-correct & x = x0 & x0 in X . s & y = y0 & y0 in X . s holds
(A \and (\not (A / (x0,y0)))) \imp (\not (x '=' (y,L))) in G1
let x0, y0 be Element of Union (X extended_by ({}, the carrier of S1)); for L being non-empty Language of X extended_by ({}, the carrier of S1),S1
for G1 being QC-theory_with_equality of L
for A being Formula of L
for s being SortSymbol of S1 st L is subst-correct & x = x0 & x0 in X . s & y = y0 & y0 in X . s holds
(A \and (\not (A / (x0,y0)))) \imp (\not (x '=' (y,L))) in G1
let L be non-empty Language of X extended_by ({}, the carrier of S1),S1; for G1 being QC-theory_with_equality of L
for A being Formula of L
for s being SortSymbol of S1 st L is subst-correct & x = x0 & x0 in X . s & y = y0 & y0 in X . s holds
(A \and (\not (A / (x0,y0)))) \imp (\not (x '=' (y,L))) in G1
let G1 be QC-theory_with_equality of L; for A being Formula of L
for s being SortSymbol of S1 st L is subst-correct & x = x0 & x0 in X . s & y = y0 & y0 in X . s holds
(A \and (\not (A / (x0,y0)))) \imp (\not (x '=' (y,L))) in G1
let A be Formula of L; for s being SortSymbol of S1 st L is subst-correct & x = x0 & x0 in X . s & y = y0 & y0 in X . s holds
(A \and (\not (A / (x0,y0)))) \imp (\not (x '=' (y,L))) in G1
let s be SortSymbol of S1; ( L is subst-correct & x = x0 & x0 in X . s & y = y0 & y0 in X . s implies (A \and (\not (A / (x0,y0)))) \imp (\not (x '=' (y,L))) in G1 )
assume that
A0:
L is subst-correct
and
A1:
( x = x0 & x0 in X . s & y = y0 & y0 in X . s )
; (A \and (\not (A / (x0,y0)))) \imp (\not (x '=' (y,L))) in G1
( s in dom X & dom X = the carrier of J )
by A1, FUNCT_1:def 2, PARTFUN1:def 2;
then
( X . s c= the Sorts of T . s & the Sorts of T . s = the Sorts of L . s )
by Th16, PBOOLE:def 2, PBOOLE:def 18;
then reconsider t1 = x, t2 = y as Element of L,s by A1;
( (A \and (x '=' (y,L))) \imp (A / (x0,y0)) in G1 & ((A \and (t1 '=' (t2,L))) \imp (A / (x0,y0))) \imp (A \imp ((t1 '=' (t2,L)) \imp (A / (x0,y0)))) in G1 )
by A0, A1, ThTwo, Th47;
then
( A \imp ((t1 '=' (t2,L)) \imp (A / (x0,y0))) in G1 & ((t1 '=' (t2,L)) \imp (A / (x0,y0))) \imp ((\not (A / (x0,y0))) \imp (\not (t1 '=' (t2,L)))) in G1 )
by Def38, Th57;
then
( A \imp ((\not (A / (x0,y0))) \imp (\not (t1 '=' (t2,L)))) in G1 & (A \imp ((\not (A / (x0,y0))) \imp (\not (t1 '=' (t2,L))))) \imp ((A \and (\not (A / (x0,y0)))) \imp (\not (t1 '=' (t2,L)))) in G1 )
by Th45, Th48;
hence
(A \and (\not (A / (x0,y0)))) \imp (\not (x '=' (y,L))) in G1
by Def38; verum