proposition: Lemma foot_simpl: forall A (a1 a2 : A) (L : list A), foot (a1 :: a2 :: L) = foot (a2 :: L).
proof: Proof. intros. simpl. destruct L; 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