matita/matita/contribs/lambdadelta/ground/xoa/ex_4_1_props.ma

   1 (**************************************************************************)
   2 (*       ___                                                              *)
   3 (*      ||M||                                                             *)
   4 (*      ||A||       A project by Andrea Asperti                           *)
   5 (*      ||T||                                                             *)
   6 (*      ||I||       Developers:                                           *)
   7 (*      ||T||         The HELM team.                                      *)
   8 (*      ||A||         http://helm.cs.unibo.it                             *)
   9 (*      \   /                                                             *)
  10 (*       \ /        This file is distributed under the terms of the       *)
  11 (*        v         GNU General Public License Version 2                  *)
  12 (*                                                                        *)
  13 (**************************************************************************)
  14
  15 (* LOGIC ********************************************************************)
  16
  17 include "ground/xoa/ex_4_1.ma".
  18
  19 (* Constructions with ex4 ***************************************************)
  20
  21 lemma ex4_commute (A0) (P0,P1,P2,P3:A0→Prop):
  22                   (∃∃x0. P0 x0 & P1 x0 & P2 x0 & P3 x0) → ∃∃x0. P2 x0 & P3 x0 & P0 x0 & P1 x0.
  23 #A0 #P0 #P1 #P2 #P3 * /2 width=5 by ex4_intro/
  24 qed-.