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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.                       *)
(*                                                                    *)
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(* License along with this program; if not, write to the Free         *)
(* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA *)
(* 02110-1301 USA                                                     *)
(* invariant pour le kill_empty states de correction par rapport a une signature *)

Lemma kill_empty_correct_wrt_sign_invar :
forall (d : DTA) (sigma : signature),
dta_correct_wrt_sign d sigma ->
dta_correct_wrt_sign (DTA_kill_empty_states d) sigma.