proposition: Lemma not_mem_in_iff m x : ~In x m <-> mem x m = false.
proof: Proof. rewrite mem_in_iff; destruct (mem x m); intuition discriminate. Qed.
imports: Coq(Bool Equalities Orders OrdersFacts OrdersLists) Coq(Morphisms Permutation SetoidPermutation) MMaps(Utils Comparisons Interface)