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