proposition: Fact meetC : commutative meet.
proof: Proof. by move=> x y; apply: le_anti; rewrite !meet_lel. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(path fintype tuple bigop finset div prime finfun) mathcomp(finset)