A Characterization of De Morgan Algebras

In this note we show that every de Morgan algebra is isomorphic to a two-subset algebra, 〈P,⊔,⊓,∼, 0P , 1P 〉, where P is a set of pairs (X,Y ) of subsets of a set I, (X,Y )⊔(X , Y ) = (X∩X , Y ∪Y ), (X,Y )⊓(X , Y ) = (X ∪ X , Y ∩ Y ), ∼ (X,Y ) = (Y,X), 1P = (∅, I), and 0P = (I, ∅). This characterization generalizes a previous result that applied only to a special type of de Morgan algebras called ternary algebras.