proposition: Lemma mem_enum (A : {pred T}) : enum A =i A.
proof: Proof. by move=> x; rewrite mem_sort mem_enum. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(path fintype tuple bigop finset div prime finfun) mathcomp(finset)