milestone update in ground

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

diff --git a/matita/matita/contribs/lambdadelta/ground/relocation/gr_isi_id.ma b/matita/matita/contribs/lambdadelta/ground/relocation/gr_isi_id.ma
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+++ b/matita/matita/contribs/lambdadelta/ground/relocation/gr_isi_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/relocation/gr_id.ma".
+include "ground/relocation/gr_isi_eq.ma".
+
+(* IDENTITY CONDITION FOR GENERIC RELOCATION MAPS ***********************************************************)
+
+(* Properties with gr_id *********************************************************)
+
+(*** id_isid *)
+lemma gr_isi_id: 𝐈❪𝐢❫.
+/2 width=1 by gr_eq_push_isi/ qed.
+
+(* Alternative definition with gr_id and gr_eq *******************************************)
+
+(*** eq_id_isid *)
+lemma gr_eq_id_isi (f): 𝐢 ≡ f → 𝐈❪f❫.
+/2 width=3 by gr_isi_eq_repl_back/ qed.
+
+(*** eq_id_inv_isid *)
+lemma gr_isi_inv_eq_id (f): 𝐈❪f❫ → 𝐢 ≡ f.
+/2 width=1 by gr_isi_inv_eq_repl/ qed-.