(** The type of domains **)
Module Dom := MSetAVL.Make(X).Module Ddec := Decide(Dom).Module DProp := EqProperties(Dom).Ltac fsetdec := Ddec.fsetdec.(** The type of maps over this domain **)
Module XOT := OTconvert X.Module S := FMapList.Make(XOT).(** The type of dependent maps **)
Definition key := X.t.Definition OK {A} dom (map : S.t A) := ∀ x, S.In x map <-> Dom.In x dom.Definition t := fun A dom => { map : S.t A | OK dom map}.Instance OK_compat A : Proper (Dom.eq ==> @S.Equal A ==> iff) OK.

Lemma empty_OK : forall A, OK Dom.empty (S.empty A).