let q, r, p be Element of CQC-WFF ; :: thesis: ((q => r) => p) => ((q => p) => p) in TAUT
( ((p => q) => q) => ((q => p) => p) in TAUT & (((p => q) => q) => ((q => p) => p)) => (((q => r) => p) => ((q => p) => p)) in TAUT ) by Lm16, Lm17;
hence ((q => r) => p) => ((q => p) => p) in TAUT by CQC_THE1:82; :: thesis: verum