proposition: Lemma add_edge_iso'' F G (h: F ≃ G) x x' (ex: h x = x') y y' (ey: h y = y') u v (e: u ≡ v): F ∔ [x, u, y] ≃ G ∔ [x', v, y'].
proof: Proof. Iso (iso_v h) (option_bij (h.e)) (fun e => match e with Some e => h.d e | None => false end). abstract by split; rewrite -?ex -?ey; repeat first [apply h|symmetry; apply e|case]. Defined.
imports: Coq(Morphisms RelationClasses) mathcomp(all_ssreflect) GraphTheory(edone finite_quotient preliminaries bij) GraphTheory(equiv digraph setoid_bigop structures)