proposition: Lemma add_edge_remove_edges (G : pre_graph) e E x y u : e \notin E -> G ∔ [e,x,u,y] - E ≡G (G - E) ∔ [e,x,u,y].
proof: Proof. move => He. split => //=. by rewrite fsetUDl mem_fsetD1. 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)