let p be Element of CQC-WFF ; :: thesis: for X being Subset of CQC-WFF st p in X holds
X |- p
let X be Subset of CQC-WFF; :: thesis: ( p in X implies X |- p )
X c= Cn X by CQC_THE1:17;
hence ( p in X implies X |- p ) by CQC_THE1:def 8; :: thesis: verum