proposition: Lemma comparable_contra_not_le P x y : x >=< y -> (y < x -> P) -> (~ P -> x <= y).
proof: Proof. by case: comparableP => // _ _ /(_ isT). Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(path fintype tuple bigop finset div prime finfun) mathcomp(finset)