let t, q, p, r be Element of CQC-WFF ; :: thesis: ((t => ((q => p) => p)) => r) => ((('not' p) => q) => r) in TAUT
( (('not' p) => q) => (t => ((q => p) => p)) in TAUT & ((('not' p) => q) => (t => ((q => p) => p))) => (((t => ((q => p) => p)) => r) => ((('not' p) => q) => r)) in TAUT ) by Lm9, Th1;
hence ((t => ((q => p) => p)) => r) => ((('not' p) => q) => r) in TAUT by CQC_THE1:46; :: thesis: verum