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

   1 (**************************************************************************)
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   3 (*      ||M||                                                             *)
   4 (*      ||A||       A project by Andrea Asperti                           *)
   5 (*      ||T||                                                             *)
   6 (*      ||I||       Developers:                                           *)
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  10 (*       \ /        This file is distributed under the terms of the       *)
  11 (*        v         GNU General Public License Version 2                  *)
  12 (*                                                                        *)
  13 (**************************************************************************)
  14
  15 include "basics/bool.ma".
  16 include "ground/lib/relations.ma".
  17 include "ground/notation/functions/no_0.ma".
  18 include "ground/notation/functions/yes_0.ma".
  19
  20 (* BOOLEANS *****************************************************************)
  21
  22 interpretation
  23   "false (booleans)"
  24   'no = false.
  25
  26 interpretation
  27   "true (booleans)"
  28   'yes = true.
  29
  30 (* Advanced constructions ***************************************************)
  31
  32 lemma eq_bool_dec (b1:bool) (b2:bool):
  33       Decidable (b1 = b2).
  34 * * /2 width=1 by or_introl/
  35 @or_intror #H destruct
  36 qed-.