--- /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 "basic_2/relocation/fsup.ma".
+include "basic_2/relocation/ldrop_lpx_sn.ma".
+include "basic_2/substitution/cpss_lift.ma".
+include "basic_2/substitution/lpss.ma".
+
+(* SN PARALLEL SUBSTITUTION FOR LOCAL ENVIRONMENTS **************************)
+
+(* Properies on local environment slicing ***********************************)
+
+lemma lpss_ldrop_conf: dropable_sn lpss.
+/3 width=5 by lpx_sn_deliftable_dropable, cpss_inv_lift1/ qed-.
+
+lemma ldrop_lpss_trans: dedropable_sn lpss.
+/3 width=9 by lpx_sn_liftable_dedropable, cpss_lift/ qed-.
+
+lemma lpss_ldrop_trans_O1: dropable_dx lpss.
+/2 width=3 by lpx_sn_dropable/ qed-.
+
+(* Properties on context-sensitive parallel substitution for terms **********)
+
+lemma fsup_cpss_trans: ∀L1,L2,T1,T2. ⦃L1, T1⦄ ⊃ ⦃L2, T2⦄ → ∀U2. L2 ⊢ T2 ▶* U2 →
+ ∃∃L,U1. L1 ⊢ ▶* L & L ⊢ T1 ▶* U1 & ⦃L, U1⦄ ⊃ ⦃L2, U2⦄.
+#L1 #L2 #T1 #T2 #H elim H -L1 -L2 -T1 -T2 [2: * ] [1,2,3,4,5: /3 width=5/ ]
+[ #L #K #U #T #d #e #HLK #HUT #He #U2 #HU2
+ elim (lift_total U2 d e) #T2 #HUT2
+ lapply (cpss_lift … HU2 … HLK … HUT … HUT2) -HU2 -HUT /3 width=9/
+| #L1 #K1 #K2 #T1 #T2 #U1 #d #e #HLK1 #HTU1 #_ #IHT12 #U2 #HTU2
+ elim (IHT12 … HTU2) -IHT12 -HTU2 #K #T #HK1 #HT1 #HT2
+ elim (lift_total T d e) #U #HTU
+ elim (ldrop_lpss_trans … HLK1 … HK1) -HLK1 -HK1 #L2 #HL12 #HL2K
+ lapply (cpss_lift … HT1 … HL2K … HTU1 … HTU) -HT1 -HTU1 /3 width=11/
+]
+qed-.