In [2], I. B. Turksen looked at the Booleandisjunctive normal form of a term in two variables and the Boolean-conjunctive normal form of that term. He concluded that for some cases of certain families, when these forms are interpreted in a De Morgan system by replacing the meet by a t-norm and the join by the dual t-conorm, the disjunctive normal form is contained in the conjunctive normal f...
