let X be Subset of CQC-WFF ; :: thesis: for p being Element of CQC-WFF
for x being bound_QC-variable holds (All x,p) => p in Cn X
let p be Element of CQC-WFF ; :: thesis: for x being bound_QC-variable holds (All x,p) => p in Cn X
let x be bound_QC-variable; :: thesis: (All x,p) => p in Cn X
for T being Subset of CQC-WFF st T is being_a_theory & X c= T holds
(All x,p) => p in T by Def1;
hence (All x,p) => p in Cn X by Def2; :: thesis: verum