“…The operator negation is an automorphism ¬ : S n → S n , that is: ¬(A + B) = ¬A + (¬B), and involution: ¬(¬A) = A. These properties can be checked experimentally, say, by a CESTAC-like method, see e. g. [8], [9], [10]. So, we next consider these properties as axiomatically given, and we want to derive some simple consequences.…”