--- /dev/null
+(**************************************************************************)
+(* ___ *)
+(* ||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 "delayed_updating/syntax/path.ma".
+include "delayed_updating/notation/functions/power_2.ma".
+include "ground/arith/nat_succ_iter.ma".
+
+(* *)
+
+definition labels (l) (n:nat): path ā
+ ((list_lcons ? l)^n) (š).
+
+interpretation
+ "labels (path)"
+ 'Power l n = (labels l n).
+
+(* Basic constructions ******************************************************)
+
+lemma labels_unfold (l) (n):
+ ((list_lcons ? l)^n) (š) = lāān.
+// qed.
+
+lemma labels_zero (l):
+ (š) = lāāš.
+// qed.
+
+lemma labels_succ (l) (n):
+ lā(lāān) = lāā(ān).
+#l #n
+<labels_unfold <labels_unfold <niter_succ //
+qed.