let p, q be Element of CQC-WFF ; :: thesis: for X being Subset of CQC-WFF st X |- p holds
X |- (p => q) => q
let X be Subset of CQC-WFF ; :: thesis: ( X |- p implies X |- (p => q) => q )
assume A1: X |- p ; :: thesis: X |- (p => q) => q
X |- p => ((p => q) => q) by Th51, CQC_THE1:98;
hence X |- (p => q) => q by A1, CQC_THE1:92; :: thesis: verum