fact: Axiom uniq_app_iff : uniq (E ++ F) <-> uniq E /\ uniq F /\ disjoint E F.
imports: Coq.FSets.FSets Coq.Lists.List Coq.Logic.Decidable Metalib.CoqFSetDecide Metalib.CoqListFacts Metalib.AssocList Metalib.MetatheoryAtom Metalib.LibTactics