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1 (**************************************************************************)
2 (*       ___                                                              *)
3 (*      ||M||                                                             *)
4 (*      ||A||       A project by Andrea Asperti                           *)
5 (*      ||T||                                                             *)
6 (*      ||I||       Developers:                                           *)
7 (*      ||T||         The HELM team.                                      *)
8 (*      ||A||         http://helm.cs.unibo.it                             *)
9 (*      \   /                                                             *)
10 (*       \ /        This file is distributed under the terms of the       *)
11 (*        v         GNU General Public License Version 2                  *)
12 (*                                                                        *)
13 (**************************************************************************)
14
15 include "ground_2/notation/functions/drop_1.ma".
16 include "ground_2/steps/rtc.ma".
17
18 (* RT-TRANSITION COUNTER ****************************************************)
19
20 definition shift (r:rtc): rtc ≝ match r with
21 [ mk_rtc ri rh ti th ⇒ 〈ri+rh, 0, ti+th, 0〉 ].
22
23 interpretation "shift (rtc)"
24    'Drop r = (shift r).
25
26 (* Basic properties *********************************************************)
27
28 lemma shift_refl: ∀ri,ti. 〈ri, 0, ti, 0〉 = ↓〈ri, 0, ti, 0〉.
29 normalize //
30 qed.