proposition: Lemma decides_and : forall b b' P Q, decides b P -> decides b' Q -> decides (andb b b') (P /\ Q).
proof: Proof. destruct b; destruct b'; simpl in *; intuition. Qed.
imports: Fiat.Computation Fiat.Common.DecideableEnsembles Fiat.Narcissus.Common.Specs Fiat.Narcissus.Common.Notations