proposition: Lemma fresh_app_r : uniq (F ++ E) -> binds x a F -> ~ In x (dom E).
proof: Proof. clear. intros. assert (In x (dom F)) by eauto using binds_In. solve_uniq. Qed.
imports: Coq.FSets.FSets Coq.Lists.List Coq.Logic.Decidable Coq.Strings.String String Metalib.CoqFSetDecide Metalib.CoqListFacts Metalib.LibTactics Metalib.CoqFSetInterface Coq.Classes.Equivalence Coq.Classes.EquivDec Metalib.CoqEqDec