matita/matita/contribs/lambdadelta/ground/lib/list_tl.ma

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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 "ground/notation/functions/downharpoonright_2.ma".
  16 include "ground/lib/list.ma".
  17
  18 (* TAIL FOR LISTS ***********************************************************)
  19
  20 definition list_tl (A:Type[0]): list A → list A.
  21 #A * [ @(ⓔ) | #_ #t @t ]
  22 defined.
  23
  24 interpretation
  25   "tail (streams)"
  26   'DownHarpoonRight A t = (list_tl A t).
  27
  28 (* Basic constructions ******************************************************)
  29
  30 lemma list_tl_empty (A):
  31       ⓔ = ⇂{A}ⓔ.
  32 // qed.
  33
  34 lemma list_tl_lcons (A) (a) (t):
  35       t = ⇂{A}(a⨮t).
  36 // qed.