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[helm.git] / matita / matita / contribs / lambdadelta / ground / relocation / pr_after_uni.ma
diff --git a/matita/matita/contribs/lambdadelta/ground/relocation/pr_after_uni.ma b/matita/matita/contribs/lambdadelta/ground/relocation/pr_after_uni.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/arith/nat_plus.ma".
+(* * it should not depend on pr_isi *)
+include "ground/relocation/pr_isi_uni.ma".
+include "ground/relocation/pr_after_isi.ma".
+
+(* RELATIONAL COMPOSITION FOR PARTIAL RELOCATION MAPS ***********************)
+
+(* Constructions with pr_uni ************************************************)
+
+(*** after_uni *)
+lemma pr_after_uni (h1) (h2): 𝐮❨h1❩ ⊚ 𝐮❨h2❩ ≘ 𝐮❨h2+h1❩.
+#h1 @(nat_ind_succ … h1) -h1
+/3 width=5 by pr_after_isi_sn, pr_after_next, eq_f/
+qed.
+
+(*** after_uni_sn_pushs *)
+lemma pr_after_uni_sn_pushs (h):
+      ∀f. 𝐮❨h❩ ⊚ f ≘ ↑*[h]f.
+#h @(nat_ind_succ … h) -h
+/2 width=5 by pr_after_isi_sn, pr_after_next/
+qed.
+
+lemma pr_after_uni_isi_next (h1):
+      ∀f2. 𝐈❪f2❫ → 𝐮❨h1❩ ⊚ ↑f2 ≘ ↑𝐮❨h1❩.
+#h1 @(nat_ind_succ … h1) -h1
+/5 width=7 by pr_after_isi_dx, pr_after_eq_repl_back_sn, pr_after_next, pr_after_push, pr_isi_inv_eq_push/
+qed.
+
+lemma pr_after_uni_next_sn (h2):
+      ∀f1,f. ↑𝐮❨h2❩ ⊚ f1 ≘ f → 𝐮❨h2❩ ⊚ ↑f1 ≘ f.
+#h2 @(nat_ind_succ … h2) -h2
+[ #f1 #f #Hf
+  elim (pr_after_inv_next_sn … Hf) -Hf [2,3: // ] #g #Hg #H0 destruct
+  /4 width=7 by pr_after_isi_inv_sn, pr_after_isi_sn, pr_after_eq_repl_back, pr_eq_next/
+| #h2 #IH #f1 #f #Hf
+  elim (pr_after_inv_next_sn … Hf) -Hf [2,3: // ] #g #Hg #H0 destruct
+  /3 width=5 by pr_after_next/
+]
+qed.