proposition: Theorem lt_1_mul_pos : forall n m, 1 < n -> 0 < m -> 1 < n * m.
proof: Proof. intros n m H1 H2. apply (mul_lt_mono_pos_r m) in H1. - rewrite mul_1_l in H1. now apply lt_1_l with m. - assumption. Qed.
imports: NZAxioms NZAddOrder