--- /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/dynamic/lsubsv_lstas.ma".
+
+(* LOCAL ENVIRONMENT REFINEMENT FOR STRATIFIED NATIVE VALIDITY **************)
+
+(* Properties on decomposed extended parallel computation on terms **********)
+
+lemma lsubsv_scpds_trans: ∀h,g,G,L2,T1,T2,l. ⦃G, L2⦄ ⊢ T1 •*➡*[h, g, l] T2 →
+ ∀L1. G ⊢ L1 ⫃¡[h, g] L2 →
+ ∃∃T. ⦃G, L1⦄ ⊢ T1 •*➡*[h, g, l] T & ⦃G, L1⦄ ⊢ T2 ➡* T.
+#h #g #G #L2 #T1 #T2 #l2 * #T #l1 #Hl21 #Hl1 #HT1 #HT2 #L1 #HL12
+lapply (lsubsv_cprs_trans … HL12 … HT2) -HT2 #HT2
+elim (lsubsv_lstas_trans … HT1 … Hl1 … HL12) // #T0 #HT10 #HT0
+lapply (cpcs_cprs_strap1 … HT0 … HT2) -T #HT02
+elim (cpcs_inv_cprs … HT02) -HT02
+/5 width=5 by lsubsv_fwd_lsubd, lsubd_da_trans, ex4_2_intro, ex2_intro/
+qed-.