proposition: Lemma eqv_testE a b of is_test a & is_test b : [a] ≡ [b] <-> a ≡ b.
proof: Proof. by []. Qed.
imports: HB(structures) Coq(Setoid Morphisms) mathcomp(all_ssreflect) GraphTheory(edone preliminaries setoid_bigop structures)