proposition: Lemma dot2one' (F: graph2): F · 1 ≃2 F.
proof: Proof. irewrite (merge_union_K_l (K:=g2_one) _ _ (k:=fun _ => output))=>//. apply merge2_nothing. repeat (constructor =>//). intros []; apply /eqquotP; eqv. Qed.
imports: HB(structures) Coq(Setoid Morphisms) mathcomp(all_ssreflect) GraphTheory(edone finite_quotient preliminaries bij equiv) GraphTheory(setoid_bigop structures pttdom mgraph ptt)