fact: Fixpoint satisfies (I : valuation) (s : form) := match s with | Incl X Y => {subset I X <= I Y} | Less X Y => forall x y, x \in I X -> y \in I Y -> x < y | FF => False | Imp s t => satisfies I s -> satisfies I t | Ex s => exists N, satisfies (cons N I) s end.
imports: mathcomp(all_ssreflect) RegLang(misc languages dfa nfa regexp)