proposition: Lemma meet_sl_le_spec x y : x ≤ y <-> x ⊓ y = x.
proof: Proof. split; intros E. - apply meet_l;trivial. - rewrite <-E. apply meet_lb_r. Qed.
imports: HoTT.Classes.interfaces.abstract_algebra HoTT.Classes.interfaces.orders HoTT.Classes.orders.semirings HoTT.Classes.theory.lattices