update in ground

[helm.git] / matita / matita / contribs / lambdadelta / ground / relocation / pr_id.ma

diff --git a/matita/matita/contribs/lambdadelta/ground/relocation/pr_id.ma b/matita/matita/contribs/lambdadelta/ground/relocation/pr_id.ma
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+(**************************************************************************)
+(*       ___                                                              *)
+(*      ||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/element_i_0.ma".
+include "ground/relocation/pr_map.ma".
+
+(* IDENTITY ELEMENT FOR PARTIAL RELOCATION MAPS *****************************)
+
+(*** id *)
+corec definition pr_id: pr_map ≝ ⫯pr_id.
+
+interpretation
+  "identity element (partial relocation streams)"
+  'ElementI = (pr_id).
+
+(* Basic constructions (specific) *******************************************)
+
+(*** id_rew *)
+lemma pr_id_unfold: ⫯𝐢 = 𝐢.
+<(stream_unfold … (𝐢)) in ⊢ (???%); //
+qed.