lambda: some refactoring + support for subsets of subterms started

[helm.git] / matita / matita / contribs / lambda / length.ma

diff --git a/matita/matita/contribs/lambda/length.ma b/matita/matita/contribs/lambda/length.ma
deleted file mode 100644 (file)
index abb6294..0000000
--- a/matita/matita/contribs/lambda/length.ma
+++ /dev/null
@@ -1,31 +0,0 @@
-(**************************************************************************)
-(*       ___                                                              *)
-(*      ||M||                                                             *)
-(*      ||A||       A project by Andrea Asperti                           *)
-(*      ||T||                                                             *)
-(*      ||I||       Developers:                                           *)
-(*      ||T||         The HELM team.                                      *)
-(*      ||A||         http://helm.cs.unibo.it                             *)
-(*      \   /                                                             *)
-(*       \ /        This file is distributed under the terms of the       *)
-(*        v         GNU General Public License Version 2                  *)
-(*                                                                        *)
-(**************************************************************************)
-
-include "lift.ma".
-
-(* LENGTH *******************************************************************)
-
-(* Note: this gives the number of abstractions and applications in M *)
-let rec length M on M ≝ match M with
-[ VRef i   ⇒ 0
-| Abst A   ⇒ length A + 1
-| Appl B A ⇒ (length B) + (length A) + 1
-].
-
-interpretation "term length"
-   'card M = (length M).
-
-lemma length_lift: ∀h,M,d. |↑[d, h] M| = |M|.
-#h #M elim M -M normalize //
-qed.