matita/matita/contribs/lambdadelta/delayed_updating/reduction/dfr_lift.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 include "delayed_updating/reduction/dfr.ma".
  16 include "delayed_updating/reduction/ifr.ma".
  17 (*
  18 include "delayed_updating/unwind/unwind2_constructors.ma".
  19 include "delayed_updating/unwind/unwind2_preterm_fsubst.ma".
  20 include "delayed_updating/unwind/unwind2_preterm_eq.ma".
  21 include "delayed_updating/unwind/unwind2_prototerm_lift.ma".
  22 include "delayed_updating/unwind/unwind2_rmap_head.ma".
  23 *)
  24 include "delayed_updating/substitution/fsubst_eq.ma".
  25 include "delayed_updating/substitution/lift_prototerm_eq.ma".
  26
  27 include "delayed_updating/syntax/prototerm_proper_constructors.ma".
  28
  29 (* DELAYED FOCUSED REDUCTION ************************************************)
  30
  31 (* Constructions with lift **************************************************)
  32
  33 theorem dfr_lift_bi (f) (p) (q) (t1) (t2): (*t1 ϵ 𝐓 → *)
  34         t1 ➡𝐝𝐟[p,q] t2 → ↑[f]t1 ➡𝐟[↑[f]p,↑[↑[p◖𝗔◖𝗟]f]q] ↑[f]t2.
  35 #f #p #q #t1 #t2
  36 * #n * #H1n #Ht1 #Ht2
  37 @(ex_intro … ((↑[p●𝗔◗𝗟◗q]f)＠⧣❨n❩)) @and3_intro
  38 [ -Ht1 -Ht2
  39   >H1n >path_head_structure_depth <H1n -H1n //
  40 | lapply (in_comp_unwind2_path_term f … Ht1) -Ht2 -Ht1 -H0t1
  41   <unwind2_path_d_dx <depth_structure
  42   >list_append_rcons_sn in H1n; <reverse_append #H1n
  43   lapply (unwind2_rmap_append_pap_closed f … H1n)
  44   <reverse_lcons <depth_L_dx #H2n
  45   lapply (eq_inv_ninj_bi … H2n) -H2n #H2n <H2n -H2n -H1n #Ht1 //
  46 | lapply (unwind2_term_eq_repl_dx f … Ht2) -Ht2 #Ht2
  47   @(subset_eq_trans … Ht2) -t2
  48   @(subset_eq_trans … (unwind2_term_fsubst …))
  49   [ @fsubst_eq_repl [ // | // ]
  50     @(subset_eq_trans … (unwind2_term_iref …))
  51     @(subset_eq_canc_sn … (lift_term_eq_repl_dx …))
  52     [ @unwind2_term_grafted_S /2 width=2 by ex_intro/ | skip ] -Ht1
  53     @(subset_eq_trans … (unwind2_lift_term_after …))
  54     @unwind2_term_eq_repl_sn
  55 (* Note: crux of the proof begins *)
  56     @nstream_eq_inv_ext #m
  57     <tr_compose_pap <tr_compose_pap
  58     <tr_uni_pap <tr_uni_pap <tr_pap_plus
  59     >list_append_rcons_sn in H1n; <reverse_append #H1n
  60     lapply (unwind2_rmap_append_pap_closed f … H1n) #H2n
  61     >nrplus_inj_dx in ⊢ (???%); <H2n -H2n
  62     lapply (tls_unwind2_rmap_append_closed f … H1n) #H2n
  63     <(tr_pap_eq_repl … H2n) -H2n -H1n //
  64 (* Note: crux of the proof ends *)
  65   | //
  66   | /2 width=2 by ex_intro/
  67   | //
  68   ]
  69 ]
  70 qed.