proposition: Lemma contra_ltn_le m n z t : (t < z -> (n <= m)%N) -> ((m < n)%N -> z <= t).
proof: Proof. exact: comparable_contra_ltn_le. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(path fintype tuple bigop finset div prime finfun) mathcomp(finset)