proposition: Lemma map_id {A} : forall (ls : list A), List.map id ls = ls.
proof: Proof. induction ls. reflexivity. simpl. rewrite IHls. unfold id. reflexivity. Qed.
imports: Fiat.QueryStructure.Implementation.DataStructures.Bags.BagsInterface Fiat.QueryStructure.Implementation.DataStructures.Bags.BagsProperties Coq.Arith.PeanoNat Coq.FSets.FMapInterface Coq.FSets.FMapFacts Coq.FSets.FMapAVL Fiat.Common Fiat.Common.List.ListFacts Fiat.Common.List.FlattenList Fiat.Common.SetEqProperties Fiat.Common.FMapExtensions Fiat.Common.List.PermutationFacts