+(**************************************************************************)
+(* ___ *)
+(* ||M|| *)
+(* ||A|| A project by Andrea Asperti *)
+(* ||T|| *)
+(* ||I|| Developers: *)
+(* ||T|| The HELM team. *)
+(* ||A|| http://helm.cs.unibo.it *)
+(* \ / *)
+(* \ / This file is distributed under the terms of the *)
+(* v GNU General Public License Version 2 *)
+(* *)
+(**************************************************************************)
+
+include "ground/notation/functions/downharpoonright_2.ma".
+include "ground/lib/list.ma".
+
+(* TAIL FOR LISTS ***********************************************************)
+
+definition list_tl (A:Type[0]): list A → list A.
+#A * [ @(ⓔ) | #_ #t @t ]
+defined.
+
+interpretation
+ "tail (streams)"
+ 'DownHarpoonRight A t = (list_tl A t).
+
+(* Basic constructions ******************************************************)
+
+lemma list_tl_empty (A):
+ ⓔ = ⇂{A}ⓔ.
+// qed.
+
+lemma list_tl_lcons (A) (a) (t):
+ t = ⇂{A}(a⨮t).
+// qed.