proposition: Lemma positive_Z (z: Z): Z.lt 0 z -> sig (fun p: positive => Zpos p = z).
proof: Proof. destruct z; intros. intros. elim (Z.lt_irrefl _ H). exists p. reflexivity. exfalso. apply (Zlt_asym _ _ H). auto with *. Defined.
imports: Coq.QArith.QArith Coq.QArith.Qpower CoRN.model.ordfields.Qordfield CoRN.algebra.COrdFields2 Coq.Logic.Eqdep_dec CoRN.tactics.CornTac Coq.QArith.Qround Coq.QArith.Qabs CoRN.stdlib_omissions.Q