matita/matita/contribs/lambdadelta/basic_2/static/fle_drops.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 "basic_2/syntax/lveq_length.ma".
  16 include "basic_2/static/frees_drops.ma".
  17 include "basic_2/static/fle.ma".
  18
  19 (* FREE VARIABLES INCLUSION FOR RESTRICTED CLOSURES *************************)
  20
  21 (* Advanced properties ******************************************************)
  22
  23 lemma fle_lifts_sn: ∀T1,U1. ⬆*[1] T1 ≡ U1 → ∀L1,L2. |L2| ≤ |L1| →
  24                     ∀T2. ⦃L1, T1⦄ ⊆ ⦃L2, T2⦄ → ⦃L1.ⓧ, U1⦄ ⊆ ⦃L2, T2⦄.
  25 #T1 #U1 #HTU1 #L1 #L2 #H1L #T2
  26 * #n #m #f #g #Hf #Hg #H2L #Hfg
  27 lapply (lveq_length_fwd_dx … H2L ?) // -H1L #H destruct
  28 lapply (frees_lifts_SO (Ⓣ) (L1.ⓧ) … HTU1 … Hf)
  29 [ /3 width=4 by drops_refl, drops_drop/ ] -T1 #Hf
  30 @(ex4_4_intro … Hf Hg) /2 width=4 by lveq_void_sn/ (**) (* explict constructor *)
  31 qed-.
  32
  33 (* Advanced inversion lemmas ************************************************)
  34
  35 lemma fle_inv_lifts_sn: ∀T1,U1. ⬆*[1] T1 ≡ U1 →
  36                         ∀I1,I2,L1,L2,V1,V2,U2. ⦃L1.ⓑ{I1}V1,U1⦄ ⊆ ⦃L2.ⓑ{I2}V2, U2⦄ →
  37                         ∀p. ⦃L1, T1⦄ ⊆ ⦃L2, ⓑ{p,I2}V2.U2⦄.
  38 #T1 #U1 #HTU1 #I1 #I2 #L1 #L2 #V1 #V2 #U2
  39 * #n #m #f2 #g2 #Hf2 #Hg2 #HL #Hfg2 #p
  40 elim (lveq_inv_pair_pair … HL) -HL #HL #H1 #H2 destruct
  41 elim (frees_total L2 V2) #g1 #Hg1
  42 elim (sor_isfin_ex g1 (⫱g2)) /3 width=3 by frees_fwd_isfin, isfin_tl/ #g #Hg #_
  43 lapply (frees_inv_lifts_SO (Ⓣ) … Hf2 … HTU1)
  44 [1,2: /3 width=4 by drops_refl, drops_drop/ ] -U1 #Hf2
  45 lapply (sor_inv_sle_dx … Hg) #H0g
  46 /5 width=10 by frees_bind, sle_tl, sle_trans, ex4_4_intro/
  47 qed-.