--- /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_structure.ma".
+include "delayed_updating/syntax/path_inner.ma".
+
+(* STRUCTURE FOR PATH *******************************************************)
+
+(* Constructions with pic ***************************************************)
+
+lemma structure_pic (p):
+ ⊗p ϵ 𝐈.
+#p @(list_ind_rcons … p) -p
+[ <structure_empty //
+| #p * [ #n ] #IH
+ [ <structure_d_dx //
+ | <structure_m_dx //
+ | <structure_L_dx //
+ | <structure_A_dx //
+ | <structure_S_dx //
+ ]
+]
+qed.