--- /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 "ground/relocation/rtmap_isid.ma".
+
+(* RELOCATION P-STREAM ******************************************************)
+
+(* Inversion lemmas (specific) ************************************************)
+
+lemma isid_inv_seq: ∀f,p. 𝐈❪p⨮f❫ → 𝐈❪f❫ ∧ 𝟏 = p.
+#f #p #H elim (gr_isi_inv_gen … H) -H
+#g #Hg #H elim (push_inv_seq_dx … H) -H /2 width=1 by conj/
+qed-.