proposition: Lemma add_vlabel2_mon0 G x: G [tst x <- 1] ≃2 G.
proof: Proof. Iso2 (add_vlabel_mon0 x). Defined.
imports: HB(structures) Coq(Setoid Morphisms) mathcomp(all_ssreflect) GraphTheory(edone finite_quotient preliminaries bij equiv) GraphTheory(setoid_bigop structures pttdom mgraph ptt)