proposition: Lemma dom_map : dom (map f E) [=] dom E.
proof: Proof. clear. intros. induction E as [ | [? ?] ]; simpl; fsetdec. Qed.
imports: Coq.FSets.FSets Coq.Lists.List Coq.Logic.Decidable Coq.Strings.String String Metalib.CoqFSetDecide Metalib.CoqListFacts Metalib.LibTactics Metalib.CoqFSetInterface Coq.Classes.Equivalence Coq.Classes.EquivDec Metalib.CoqEqDec