proposition: Lemma binds_cons_3 : binds x a E -> binds x a ((VarAsn B y b) :: E).
proof: Proof. clear. unfold binds. simpl. right. trivial. Qed.
imports: Coq.FSets.FSets Coq.Lists.List Coq.Logic.Decidable Metalib.CoqFSetDecide Metalib.CoqListFacts Metalib.LibTactics Metalib.MetatheoryAtom Metalib.LibTactics