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