proposition: Lemma uniq_insert_mid : uniq (G ++ E) -> x `notin` dom (G ++ E) -> uniq (G ++ (one (VarAsn B x a)) ++ E).
proof: Proof. clear. solve_uniq. Qed.
imports: Coq.FSets.FSets Coq.Lists.List Coq.Logic.Decidable Metalib.CoqFSetDecide Metalib.CoqListFacts Metalib.LibTactics Metalib.MetatheoryAtom Metalib.LibTactics