(* *)
(**************************************************************************)
-include "ground_2/notation/functions/drops_2.ma".
+include "ground_2/notation/functions/downspoonstar_3.ma".
include "ground_2/lib/streams_hdtl.ma".
(* STREAMS ******************************************************************)
cases n -n [ #t @t | #n #t @tl @(tls … n t) ]
defined.
-interpretation "recursive tail (strams)" 'Drops n f = (tls ? n f).
+interpretation "iterated tail (strams)" 'DownSpoonStar A n f = (tls A n f).
(* basic properties *********************************************************)
lemma tls_rew_O (A) (t): t = tls A 0 t.
// qed.
-lemma tls_rew_S (A) (n) (t): â\86\93â\86\93*[n]t = tls A (⫯n) t.
+lemma tls_rew_S (A) (n) (t): â«°â«°*[n]t = tls A (â\86\91n) t.
// qed.
-lemma tls_S1 (A) (n) (t): â\86\93*[n]â\86\93t = tls A (⫯n) t.
+lemma tls_S1 (A) (n) (t): â«°*[n]â«°t = tls A (â\86\91n) t.
#A #n elim n -n //
qed.
-lemma tls_eq_repl (A) (n): eq_stream_repl A (λt1,t2. â\86\93*[n] t1 â\89\90 â\86\93*[n] t2).
+lemma tls_eq_repl (A) (n): eq_stream_repl A (λt1,t2. â«°*[n] t1 â\89\97 â«°*[n] t2).
#A #n elim n -n //
#n #IH * #n1 #t1 * #n2 #t2 #H elim (eq_stream_inv_seq … H) /2 width=7 by/
qed.