proposition: Lemma uniq_app_3 : uniq (E ++ F) -> disjoint E F.
proof: Proof. clear. intros H. red. induction E as [ | a E']. fsetdec. inversion H; subst. simpl_asnlist in *. lapply IHE'. fsetdec. assumption. inversion H; subst. simpl_asnlist in *. lapply IHE'. fsetdec. assumption. Qed.
imports: Coq.FSets.FSets Coq.Lists.List Coq.Logic.Decidable Metalib.CoqFSetDecide Metalib.CoqListFacts Metalib.LibTactics Metalib.MetatheoryAtom Metalib.LibTactics