proposition: Lemma pos_mult x y : 0 < x -> 0 < y -> 0 < x * y.
proof: Proof. intros xpos ypos. rewrite <-(mult_0_r x). apply (pos_mult_lt_l); assumption. Qed.
imports: HoTT.Classes.theory.apartness HoTT.Classes.interfaces.abstract_algebra HoTT.Classes.interfaces.orders HoTT.Classes.theory.rings HoTT.Classes.orders.orders HoTT.Classes.orders.maps