proposition: Lemma par2unitunit a b: unit_graph2 a ∥ unit_graph2 b ≃2 unit_graph2 (a⊗b).
proof: Proof. etransitivity. apply par2dot=>//. etransitivity. apply dot2unit_r. apply add_vlabel2_unit. Qed.
imports: HB(structures) Coq(Setoid Morphisms) mathcomp(all_ssreflect) GraphTheory(edone finite_quotient preliminaries bij equiv) GraphTheory(setoid_bigop structures pttdom mgraph ptt)