proposition: Lemma op_le_r' : ∏ k x y : X, Lle lat (x + k) (y + k) → Lle lat x y.
proof: Proof. intros k x y H. eapply rcancel. { apply is0. } now rewrite is2, H. Qed.
imports: UniMath.MoreFoundations.All UniMath.Algebra.Monoids UniMath.Algebra.Groups