proposition: Lemma In_Permutation_cons: forall {A : Type} (l : list A) (x : A), In x l -> exists l', Permutation l (x :: l').
proof: Proof. intros. induction l. + inversion H. + destruct H. - exists l; subst; reflexivity. - destruct (IHl H) as [l' ?]. exists (a :: l'). rewrite H0. constructor. Qed.
imports: Coq.Lists.List Coq.micromega.Lia Coq.Sorting.Permutation Coq.ZArith.ZArith_base Coq.ZArith.Zcomplements Coq.Logic.FunctionalExtensionality CertiGraph.lib.Coqlib CertiGraph.lib.EquivDec_ext VST.zlist.sublist VST.zlist.list_solver