proposition: Lemma semi_iso_DoubleNoDup: forall g1 g2 from to l, from <> to -> gc_graph_semi_iso g1 g2 from to l -> DoubleNoDup l.
proof: Proof. intros. destruct H0 as [_ [_ ?]]. destruct (split l) as [from_l to_l] eqn: ?. apply (PairGenNoDup_DoubleNoDup l from to); auto. red. rewrite Heqp. destruct H0 as [[? ?] [[? [? ?]] _]]. split; split; intros; auto. rewrite <- H1 in H5. destruct H5 as [_ [_ ?]]. assumption. Qed.
imports: Coq.ZArith.ZArith Coq.Program.Basics compcert.lib.Integers compcert.common.Values VST.veric.base VST.veric.Clight_lemmas VST.veric.val_lemmas VST.veric.shares VST.msl.seplog VST.msl.shares VST.zlist.sublist VST.floyd.coqlib3 VST.floyd.functional_base VST.floyd.data_at_rec_lemmas CertiGraph.lib.Coqlib CertiGraph.lib.EquivDec_ext CertiGraph.lib.List_ext CertiGraph.graph.graph_model CertiGraph.graph.graph_gen CertiGraph.graph.path_lemmas CertiGraph.graph.subgraph2 CertiGraph.graph.graph_relation CertiGraph.graph.graph_isomorphism CertiGraph.graph.reachable_ind CertiGraph.CertiGC.GCGraph