  By a De Morgan algebra is meant a bounded poset equipped with an antitone
involution considered as negation. Such an algebra can be considered as an
algebraic axiomatization of a propositional logic satisfying the double
negation law. Our aim is to introduce the so-called tense operators in every De
Morgan algebra for to get an algebraic counterpart of a tense logic with
negation satisfying the double negation law which need not be Boolean.
  Following the standard construction of tense operators $G$ and $H$ by a frame
we solve the following question: if a dynamic De Morgan algebra is given, how
to find a frame such that its tense operators $G$ and $H$ can be reached by
this construction.
