proposition: Lemma NoDup_cons_2 : forall (A : Type) (x : A) (l : list A), NoDup (x :: l) -> ~ In x l.
proof: Proof. intros. rewrite NoDup_cons_iff in H. destruct H; auto. 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