proposition: Lemma enum1 (x : T) : enum (pred1 x) = [:: x].
proof: Proof. by rewrite enum1. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(path fintype tuple bigop finset div prime finfun) mathcomp(finset)