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 L being non-empty Language of X extended_by ({}, the carrier of S1),S1
for G being QC-theory of L
for A being Formula of L
for x being Element of Union X st L is subst-correct & L is vf-qc-correct holds
(\for (x,(A \or A))) \iff (\for (x,A)) in G
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 L being non-empty Language of X extended_by ({}, the carrier of S1),S1
for G being QC-theory of L
for A being Formula of L
for x being Element of Union X st L is subst-correct & L is vf-qc-correct holds
(\for (x,(A \or A))) \iff (\for (x,A)) in G
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 L being non-empty Language of X extended_by ({}, the carrier of S1),S1
for G being QC-theory of L
for A being Formula of L
for x being Element of Union X st L is subst-correct & L is vf-qc-correct holds
(\for (x,(A \or A))) \iff (\for (x,A)) in G
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 L being non-empty Language of X extended_by ({}, the carrier of S1),S1
for G being QC-theory of L
for A being Formula of L
for x being Element of Union X st L is subst-correct & L is vf-qc-correct holds
(\for (x,(A \or A))) \iff (\for (x,A)) in G
let S1 be non empty non void J -extension n PC-correct QC-correct QCLangSignature over Union X; for L being non-empty Language of X extended_by ({}, the carrier of S1),S1
for G being QC-theory of L
for A being Formula of L
for x being Element of Union X st L is subst-correct & L is vf-qc-correct holds
(\for (x,(A \or A))) \iff (\for (x,A)) in G
let L be non-empty Language of X extended_by ({}, the carrier of S1),S1; for G being QC-theory of L
for A being Formula of L
for x being Element of Union X st L is subst-correct & L is vf-qc-correct holds
(\for (x,(A \or A))) \iff (\for (x,A)) in G
let G be QC-theory of L; for A being Formula of L
for x being Element of Union X st L is subst-correct & L is vf-qc-correct holds
(\for (x,(A \or A))) \iff (\for (x,A)) in G
let A be Formula of L; for x being Element of Union X st L is subst-correct & L is vf-qc-correct holds
(\for (x,(A \or A))) \iff (\for (x,A)) in G
let x be Element of Union X; ( L is subst-correct & L is vf-qc-correct implies (\for (x,(A \or A))) \iff (\for (x,A)) in G )
assume A1:
( L is subst-correct & L is vf-qc-correct )
; (\for (x,(A \or A))) \iff (\for (x,A)) in G
( (A \or A) \imp A in G & A \imp (A \or A) in G )
by Def38, Th52;
then A2:
( \for (x,((A \or A) \imp A)) in G & \for (x,(A \imp (A \or A))) in G )
by Def39;
( (\for (x,(A \imp (A \or A)))) \imp ((\for (x,A)) \imp (\for (x,(A \or A)))) in G & (\for (x,((A \or A) \imp A))) \imp ((\for (x,(A \or A))) \imp (\for (x,A))) in G )
by A1, Th109;
then
( (\for (x,A)) \imp (\for (x,(A \or A))) in G & (\for (x,(A \or A))) \imp (\for (x,A)) in G )
by A2, Def38;
hence
(\for (x,(A \or A))) \iff (\for (x,A)) in G
by Th43; verum