proposition: Lemma binds_In : forall x a (E : list (asn A B)), binds x a E -> x `in` dom E.
proof: Proof. clear. induction E as [ | y ? F ]; intros J; simpl_asnlist. analyze_binds J. analyze_binds J; subst; auto with set. inversion H0;subst. simpl. fsetdec. inversion H. Qed.
imports: Coq.FSets.FSets Coq.Lists.List Coq.Logic.Decidable Metalib.CoqFSetDecide Metalib.CoqListFacts Metalib.LibTactics Metalib.MetatheoryAtom Metalib.LibTactics