let r, p, s, q be Element of CQC-WFF ; :: thesis: (((r => p) => p) => s) => (((p => q) => r) => s) in TAUT
( ((p => q) => r) => ((r => p) => p) in TAUT & (((p => q) => r) => ((r => p) => p)) => ((((r => p) => p) => s) => (((p => q) => r) => s)) in TAUT ) by Lm16, Th1;
hence (((r => p) => p) => s) => (((p => q) => r) => s) in TAUT by CQC_THE1:82; :: thesis: verum