proposition: Lemma divide_Zpos_Zneg_l n p : (pos p|n) <-> (neg p|n).
proof: Proof. split; intros (m,H); exists (-m); now rewrite mul_opp_l, <- mul_opp_r. Qed.
imports: BinNums BinPos Pnat BinNat Bool Equalities GenericMinMax OrdersFacts ZAxioms ZProperties DecidableClass