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