proposition: Lemma add_edge2_iso'' F G (h: F ≃2 G) x x' (ex: h x = x') y y' (ey: h y = y') u v (e: u ≡ v): F ∔ [x, u, y] ≃2 G ∔ [x', v, y'].
proof: Proof. Iso2 (add_edge_iso'' ex ey e); apply h. Defined.
imports: HB(structures) Coq(Setoid Morphisms) mathcomp(all_ssreflect) GraphTheory(edone finite_quotient preliminaries bij equiv) GraphTheory(setoid_bigop structures pttdom mgraph ptt)