matita/matita/contribs/lambdadelta/basic_2/etc_new/frees/frees_length.etc

   1 (**************************************************************************)
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   3 (*      ||M||                                                             *)
   4 (*      ||A||       A project by Andrea Asperti                           *)
   5 (*      ||T||                                                             *)
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  10 (*       \ /        This file is distributed under the terms of the       *)
  11 (*        v         GNU General Public License Version 2                  *)
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  13 (**************************************************************************)
  14
  15 include "basic_2/grammar/lenv_length.ma".
  16 include "basic_2/grammar/cl_restricted_weight.ma".
  17 include "basic_2/relocation/frees.ma".
  18
  19 (* CONTEXT-SENSITIVE FREE VARIABLES *****************************************)
  20
  21 (* Forward lemmas on length for local environments **************************)
  22
  23 lemma frees_fwd_length: ∀L,T,t. L ⊢ 𝐅*⦃T⦄ ≡ t → |L| = |t|.
  24 #L #T #t #H elim H -L -T -t //
  25 [ #p ] #I #L #V #T #t1 #t2 #t [ #b ] #_ #_ #Ht elim (sor_inv_length … Ht) -Ht //
  26 qed-.