proposition: Lemma plus_lt_compat_l x y z : 0 < z → x < y → x < z + y.
proof: Proof. rewrite commutativity. now apply plus_lt_compat_r. Qed.
imports: Coq.setoid_ring.Ring MathClasses.interfaces.abstract_algebra MathClasses.interfaces.orders MathClasses.theory.rings MathClasses.orders.orders MathClasses.orders.maps