p | q | p nor q ---+---+--------- 0 | 0 | 1 0 | 1 | 0 1 | 0 | 0 1 | 1 | 0 ~(p nor q) not p === p nor p p and q === (p nor p) nor (q nor q) p or q === (p nor q) nor (p nor q) p xor q === [something very long]