proposition: Lemma oarc_added_edge (G : pre_graph) e x y u : oarc (G ∔ [e,x,u,y]) e x u y.
proof: Proof. split. - by rewrite !inE eqxx. - by exists false; split; rewrite /= update_eq. 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)