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