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(* modify it under the terms of the GNU Lesser General Public License *)
(* as published by the Free Software Foundation; either version 2.1   *)
(* of the License, or (at your option) any later version.             *)
(*                                                                    *)
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(* but WITHOUT ANY WARRANTY; without even the implied warranty of     *)
(* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the      *)
(* GNU General Public License for more details.                       *)
(*                                                                    *)
(* You should have received a copy of the GNU Lesser General Public   *)
(* License along with this program; if not, write to the Free         *)
(* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA *)
(* 02110-1301 USA                                                     *)
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(*          Projet Formel - Calculus of Inductive Constructions V5.10        *)
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(*									     *)
(*	Diagonal Functor (used in the definition of Cartesian) 		     *)
(*									     *)
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(*									     *)
(*                     A. SAIBI	  May 95                  		     *)
(*									     *)
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Require Export PROD.
Require Export Functor.
Set Implicit Arguments.
Unset Strict Implicit.
Section diag.
Variable C : Category.
Definition Diag_ob (c : C) := Build_POb c c.
Section diag_map_def.
Variable a b : C.
Definition Diag_mor (f : a --> b) :=
Build_Pmor (u:=Diag_ob a) (t:=Diag_ob b) f f.

(* Specifications: *)
Lemma Diag_map_law : Map_law Diag_mor.
Canonical Structure Diag_map := Build_Map Diag_map_law.