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diff --git a/matita/contribs/CoRN-Decl/model/non_examples/Npos_no_group.ma b/matita/contribs/CoRN-Decl/model/non_examples/Npos_no_group.ma
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+(**************************************************************************)
+(*       ___                                                              *)
+(*      ||M||                                                             *)
+(*      ||A||       A project by Andrea Asperti                           *)
+(*      ||T||                                                             *)
+(*      ||I||       Developers:                                           *)
+(*      ||T||         The HELM team.                                      *)
+(*      ||A||         http://helm.cs.unibo.it                             *)
+(*      \   /                                                             *)
+(*       \ /        This file is distributed under the terms of the       *)
+(*        v         GNU General Public License Version 2                  *)
+(*                                                                        *)
+(**************************************************************************)
+
+(* This file was automatically generated: do not edit *********************)
+
+set "baseuri" "cic:/matita/CoRN-Decl/model/non_examples/Npos_no_group".
+
+include "CoRN.ma".
+
+(* $Id: Npos_no_group.v,v 1.6 2004/04/08 08:20:33 lcf Exp $ *)
+
+include "algebra/CGroups.ma".
+
+include "model/monoids/Nposmonoid.ma".
+
+(*#* **Non-example of a group: $\langle$#⟨#[Npos],[[+]]$\rangle$#⟩#
+There is no inverse for multiplication on the positive natural numbers.
+*)
+
+inline "cic:/CoRN/model/non_examples/Npos_no_group/no_inverse_Nposmult.con".
+
+(*#* Hence the natural numbers with multiplication do not form a group.
+*)
+
+inline "cic:/CoRN/model/non_examples/Npos_no_group/no_group_Nposmult.con".
+