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