proposition: Lemma meet_l x y : x ≤ y → x ⊓ y = x.
proof: Proof. intros E. apply (antisymmetry (≤)). apply meet_lb_l. now apply meet_glb. Qed.
imports: MathClasses.interfaces.abstract_algebra MathClasses.interfaces.orders MathClasses.orders.maps MathClasses.theory.lattices