(************************************************************************)
(*  v      *   The Coq Proof Assistant  /  The Coq Development Team     *)
(* <O___,, * CNRS-Ecole Polytechnique-INRIA Futurs-Universite Paris Sud *)
(*   \VV/  **************************************************************)
(*    //   *      This file is distributed under the terms of the       *)
(*         *       GNU Lesser General Public License Version 2.1        *)
(************************************************************************)
(*i 	$Id$	 i*)
Section MapCard.
Variables A B : Type.

Lemma MapCard_is_one :
forall m:Map A,
MapCard A m = 1 -> {a : ad &  {y : A | MapGet A m a = Some y}}.