proposition: Lemma remove_vertexK (G : pre_graph) (isG : is_graph G) z : z \in vset G -> (G \ z) ∔ [z,lv G z] ≡G G - edges_at G z.
proof: Proof. split => //= [|x _]; by rewrite ?fsetD1K ?update_fx. Qed.
imports: HB(structures) Coq(Relation_Definitions Morphisms RelationClasses) mathcomp(all_ssreflect) GraphTheory(edone finite_quotient preliminaries bij equiv) GraphTheory(setoid_bigop structures pttdom rewriting) GraphTheory(finmap_plus)