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