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