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4 (* ||A|| A project by Andrea Asperti *)
6 (* ||I|| Developers: *)
7 (* ||T|| The HELM team. *)
8 (* ||A|| http://helm.cs.unibo.it *)
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15 include "ground/lib/stream_eq.ma".
16 include "ground/lib/stream_tls.ma".
18 (* ITERATED TAIL FOR STREAMS ************************************************)
20 (* Constructions with stream_eq *********************************************)
22 lemma stream_tls_eq_repl (A) (n):
23 stream_eq_repl A (λt1,t2. ⇣*[n] t1 ≗ ⇣*[n] t2).
24 #A #n @(nat_ind_succ … n) -n //
25 #n #IH * #n1 #t1 * #n2 #t2 #H
26 elim (stream_eq_inv_cons_bi … H) /2 width=7 by/