fact: Axiom binds_mid_eq : binds x a (F ++ (x ~ b) ++ E) -> uniq (F ++ (x ~ b) ++ E) -> a = b.
imports: Coq.FSets.FSets Coq.Lists.List Coq.Logic.Decidable Metalib.CoqFSetDecide Metalib.CoqListFacts Metalib.AssocList Metalib.MetatheoryAtom Metalib.LibTactics