1 (**************************************************************************)
4 (* ||A|| A project by Andrea Asperti *)
6 (* ||I|| Developers: *)
7 (* ||T|| The HELM team. *)
8 (* ||A|| http://helm.cs.unibo.it *)
10 (* \ / This file is distributed under the terms of the *)
11 (* v GNU General Public License Version 2 *)
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15 include "ground/arith/nat_tri.ma".
16 include "ground/arith/nat_succ.ma".
18 (* SUCCESSOR FOR NON-NEGATIVE INTEGERS **************************************)
20 (* Rewrites with ntri *******************************************************)
22 lemma ntri_succ_bi (A) (a1) (a2) (a3) (n1) (n2):
23 ntri A (n1) (n2) a1 a2 a3 = ntri A (↑n1) (↑n2) a1 a2 a3.
24 #A #a1 #a2 #a3 * [| #p1 ] * //