fact: Definition union_pregraph (PV : V -> Prop) (PE: E -> Prop) (PVD: forall v, Decidable (PV v)) (PED: forall e, Decidable (PE e)) (g1 g2: Graph): Graph := @Build_PreGraph V E EV EE (fun v => if PVD v then vvalid g1 v else vvalid g2 v) (fun e => if PED e then evalid g1 e else evalid g2 e) (fun e => if PED e then src g1 e else src g2 e) (fun e => if PED e then dst g1 e else dst g2 e).
imports: Coq.Logic.ProofIrrelevance Coq.Sets.Ensembles Coq.Sets.Finite_sets Coq.Classes.Morphisms CertiGraph.lib.Coqlib CertiGraph.lib.Ensembles_ext CertiGraph.lib.relation_list CertiGraph.lib.List_ext CertiGraph.lib.Equivalence_ext CertiGraph.lib.EquivDec_ext VST.msl.Coqlib2 Coq.Lists.List CertiGraph.graph.graph_model CertiGraph.graph.path_lemmas CertiGraph.graph.reachable_ind