let L be non empty satisfying_Sheffer_1 satisfying_Sheffer_2 satisfying_Sheffer_3 ShefferStr ; :: thesis: for p, w being Element of L holds (w | p) | (w | w) = w
let p, w be Element of L; :: thesis: (w | p) | (w | w) = w
(w | w) | (w | p) = (w | p) | (w | w) by Th83;
hence (w | p) | (w | w) = w by Th132; :: thesis: verum