proposition: Lemma eq_meetr x y : (x `&` y == y) = (y <= x).
proof: Proof. by rewrite meetC eq_meetl. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(path fintype tuple bigop finset div prime finfun) mathcomp(finset)