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 *)
13 (**************************************************************************)
15 include "ground/arith/nat_plus.ma".
16 include "ground/lib/stream_tls.ma".
18 (* ITERATED TAIL FOR STREAMS ************************************************)
20 (* Constructions with nplus *************************************************)
22 lemma stream_tls_plus (A) (n1) (n2) (t):
23 ⇂*[n1]⇂*[n2]t = ⇂*{A}[n1+n2]t.
25 <nplus_comm @(niter_plus … t)