proposition: Lemma reachable_or_marked_iff_reachable: forall g roots from v, sound_gc_graph g -> graph_unmarked g -> reachable_or_marked from g roots v <-> reachable_through_set g (filter_sum_right roots) v /\ vgeneration v = from.
proof: Proof. intros. unfold reachable_or_marked. split; intros; destruct H1; split; auto. destruct H2 as [? | [? ?]]; auto. rewrite graph_gen_unmarked_iff in H0. destruct H as [? _]. red in H. rewrite H in H2. destruct v as [gen idx]. destruct H2. simpl in *. subst gen. red in H0. rewrite H0 in H3; easy. 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