proposition: Lemma plus_mono_r (alpha beta gamma : Ord) : beta < gamma -> alpha + beta < alpha + gamma.
proof: Proof. intro H; pattern (plus alpha); apply plus_elim;auto. intros; eapply ordering_function_mono;eauto with schutte. Qed.
imports: Coq(Arith Logic.Epsilon Ensembles) ZornsLemma(CountableTypes)