proposition: Lemma add_testK (G : pre_graph) x a : G[adt x <- a] \ x ≡G G \ x.
proof: Proof. split => //= y /fsetD1P [? _]. by rewrite updateE. Qed.
imports: HB(structures) Coq(Relation_Definitions Morphisms RelationClasses) mathcomp(all_ssreflect) GraphTheory(edone finite_quotient preliminaries bij equiv) GraphTheory(setoid_bigop structures pttdom rewriting) GraphTheory(finmap_plus)