proposition: Lemma Zdivides_abs_intro : forall a b : Z, Zdivides (Z.abs a) (Z.abs b) -> Zdivides a b.
proof: Proof. intros. apply Zdivides_abs_intro_lft. apply Zdivides_abs_intro_rht. assumption. Qed.
imports: CoRN.model.Zmod.ZBasics