matita/matita/contribs/lambdadelta/static_2/syntax/bind_weight.ma

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   3 (*      ||M||                                                             *)
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  11 (*        v         GNU General Public License Version 2                  *)
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  14
  15 include "static_2/syntax/term_weight.ma".
  16 include "static_2/syntax/bind.ma".
  17
  18 (* WEIGHT OF A BINDER FOR LOCAL ENVIRONMENTS *******************************)
  19
  20 rec definition bw I ≝ match I with
  21 [ BUnit _   ⇒ 1
  22 | BPair _ V ⇒ ♯{V}
  23 ].
  24
  25 interpretation "weight (binder for local environments)" 'Weight I = (bw I).
  26
  27 (* Basic properties *********************************************************)
  28
  29 lemma bw_pos: ∀I. 1 ≤ ♯{I}.
  30 * //
  31 qed.