proposition: Lemma leCx x y : (~` x <= y) = (~` y <= x).
proof: Proof. by rewrite !complE !leBLR joinC. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(path fintype tuple bigop finset div prime finfun) mathcomp(finset)