proposition: Lemma pfoot_head_irrel: forall l (g: Gph) v1 v2 n, pfoot g (v1, n :: l) = pfoot g (v2, n :: l).
proof: Proof. induction l; intros; simpl; auto. specialize (IHl g v1 v2 a). simpl in *. apply IHl. Qed.
imports: Coq.Logic.ProofIrrelevance Coq.micromega.Lia CertiGraph.lib.Coqlib CertiGraph.lib.EnumEnsembles CertiGraph.lib.List_ext CertiGraph.lib.EquivDec_ext CertiGraph.graph.graph_model Coq.Lists.List Coq.Lists.ListDec