proposition: Lemma elements_iff' : forall (elt : Type) (m : t elt) (xe : key * elt), MapsTo (fst xe) (snd xe) m <-> InA (eq_key_elt (elt:=elt)) xe (elements (elt:=elt) m).
proof: Proof. intros; rewrite elements_iff; destruct xe; reflexivity. Qed.
imports: Coq.FSets.FMapInterface Coq.FSets.FMapFacts Coq.Program.Program Coq.Structures.OrderedTypeEx Fiat.Common Fiat.Common.SetEq Fiat.Common.SetEqProperties Fiat.Common.List.ListFacts Fiat.Common.List.ListMorphisms Fiat.Common.LogicFacts Fiat.Common.SetoidClassInstances