let A be QC-alphabet ; :: thesis: for p, q being Element of CQC-WFF A holds (p '&' q) => q in TAUT A
let p, q be Element of CQC-WFF A; :: thesis: (p '&' q) => q in TAUT A
( (q '&' p) => q in TAUT A & (p '&' q) => (q '&' p) in TAUT A ) by Th19, CQC_THE1:45;
hence (p '&' q) => q in TAUT A by LUKASI_1:3; :: thesis: verum