proposition: Lemma join_le_compat_r x y z : z ≤ x -> z ≤ x ⊔ y.
proof: Proof. intros E. transitivity x. - trivial. - apply join_ub_l. Qed.
imports: HoTT.Classes.interfaces.abstract_algebra HoTT.Classes.interfaces.orders HoTT.Classes.orders.semirings HoTT.Classes.theory.lattices