proposition: Lemma contraPle P z t : (t < z -> ~ P) -> (P -> z <= t).
proof: Proof. exact: comparable_contraPle. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(path fintype tuple bigop finset div prime finfun) mathcomp(finset)