let p, q be Element of CQC-WFF ; :: thesis: p => ((q => p) => p) in TAUT
( (('not' p) => q) => ((q => p) => p) in TAUT & ((('not' p) => q) => ((q => p) => p)) => (p => ((q => p) => p)) in TAUT ) by Lm5, Lm11;
hence p => ((q => p) => p) in TAUT by CQC_THE1:82; :: thesis: verum