proposition: Lemma Eqdom_in_add m x e : In x m -> Eqdom m (add x e m).
proof: Proof. intros IN k. rewrite add_in_iff. split; auto. intros [E|IN']; auto. now rewrite <- E. Qed.
imports: Coq(Bool Equalities Orders OrdersFacts OrdersLists) Coq(Morphisms Permutation SetoidPermutation) MMaps(Utils Comparisons Interface)