proposition: Lemma Zmult_div_simpl_2 : forall a b c d : Z, (a * b)%Z = (d * c)%Z -> a <> 0%Z -> Zdivides a c -> Zdivides d b.
proof: Proof. intros a b c d; rewrite (Zmult_comm d c); apply Zmult_div_simpl_1. Qed.
imports: CoRN.model.Zmod.ZBasics