let n be non empty Nat; for S being non empty non void n PC-correct PCLangSignature
for L being language MSAlgebra over S
for F being PC-theory of L
for A, B, C being Formula of L holds (C \imp A) \imp ((C \imp B) \imp (C \imp (A \and B))) in F
let S be non empty non void n PC-correct PCLangSignature ; for L being language MSAlgebra over S
for F being PC-theory of L
for A, B, C being Formula of L holds (C \imp A) \imp ((C \imp B) \imp (C \imp (A \and B))) in F
let L be language MSAlgebra over S; for F being PC-theory of L
for A, B, C being Formula of L holds (C \imp A) \imp ((C \imp B) \imp (C \imp (A \and B))) in F
let F be PC-theory of L; for A, B, C being Formula of L holds (C \imp A) \imp ((C \imp B) \imp (C \imp (A \and B))) in F
let A, B, C be Formula of L; (C \imp A) \imp ((C \imp B) \imp (C \imp (A \and B))) in F
A1:
(C \imp (B \imp (A \and B))) \imp ((C \imp B) \imp (C \imp (A \and B))) in F
by Def38;
A \imp (B \imp (A \and B)) in F
by Def38;
then A2:
C \imp (A \imp (B \imp (A \and B))) in F
by Th44;
(C \imp (A \imp (B \imp (A \and B)))) \imp ((C \imp A) \imp (C \imp (B \imp (A \and B)))) in F
by Def38;
then
(C \imp A) \imp (C \imp (B \imp (A \and B))) in F
by A2, Def38;
hence
(C \imp A) \imp ((C \imp B) \imp (C \imp (A \and B))) in F
by A1, Th45; verum