proposition: Lemma meetCA : left_commutative (@meet _ L).
proof: Proof. by move=> x y z; rewrite !meetA [X in X `&` _]meetC. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(path fintype tuple bigop finset div prime finfun) mathcomp(finset)