proposition: Lemma plus_le_compat_r x y z : 0 ≤ z → x ≤ y → x ≤ y + z.
proof: Proof. intros. rewrite <-(plus_0_r x). now apply plus_le_compat. Qed.
imports: Coq.setoid_ring.Ring MathClasses.interfaces.abstract_algebra MathClasses.interfaces.orders MathClasses.theory.rings MathClasses.orders.orders MathClasses.orders.maps