proposition: Lemma add_edge_iso F G (h: F ≃ G) x u y: F ∔ [x, u, y] ≃ G ∔ [h x, u, h y].
proof: Proof. by apply add_edge_iso'. Defined.
imports: Coq(Morphisms RelationClasses) mathcomp(all_ssreflect) GraphTheory(edone finite_quotient preliminaries bij) GraphTheory(equiv digraph setoid_bigop structures)