matita/matita/contribs/lambdadelta/ground/relocation/gr_isu_tl.ma

   1 (**************************************************************************)
   2 (*       ___                                                              *)
   3 (*      ||M||                                                             *)
   4 (*      ||A||       A project by Andrea Asperti                           *)
   5 (*      ||T||                                                             *)
   6 (*      ||I||       Developers:                                           *)
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   9 (*      \   /                                                             *)
  10 (*       \ /        This file is distributed under the terms of the       *)
  11 (*        v         GNU General Public License Version 2                  *)
  12 (*                                                                        *)
  13 (**************************************************************************)
  14
  15 include "ground/relocation/gr_tl.ma".
  16 include "ground/relocation/gr_isu.ma".
  17
  18 (* UNIFORMITY CONDITION FOR GENERIC RELOCATION MAPS *************************)
  19
  20 (* Constructions with gr_tl *************************************************)
  21
  22 lemma gr_isu_tl (f): 𝐔❪f❫ → 𝐔❪⫰f❫.
  23 #f cases (gr_map_split_tl f) * #H
  24 [ /3 width=3 by gr_isu_inv_push, gr_isu_isi/
  25 | /2 width=3 by gr_isu_inv_next/
  26 ]
  27 qed.
  28
  29 (* Advanced inversions ******************************************************)
  30
  31 (*** isuni_split *)
  32 lemma gr_isu_split (g): 𝐔❪g❫ → ∨∨ (∃∃f. 𝐈❪f❫ & ⫯f = g) | (∃∃f.𝐔❪f❫ & ↑f = g).
  33 #g elim (gr_map_split_tl g) * #H
  34 /4 width=3 by gr_isu_inv_next, gr_isu_inv_push, or_introl, or_intror, ex2_intro/
  35 qed-.