(***************************************************************************)
(* Formalization of the Chou, Gao and Zhang's decision procedure.          *)
(* Julien Narboux (Julien@narboux.fr)                                      *)
(* LIX/INRIA FUTURS 2004-2006                                              *)
(* University of Strasbourg 2008                                           *)
(***************************************************************************)
(* on_line *)
(* on_line_d *)
(* inter_ll *)

Lemma  test_inter_ll_1 : forall I A B C D X Y,
inter_ll I A B C D -> Py I X Y = Py Y X I.