--- /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 "static_2/static/reqx_req.ma".
+include "basic_2/rt_transition/rpx_reqx.ma".
+include "basic_2/rt_transition/rpx_lpx.ma".
+
+(* EXTENDED PARALLEL RT-TRANSITION FOR FULL LOCAL ENVIRONMENTS **************)
+
+(* Properties with sort-irrelevant equivalence for local environments *******)
+
+lemma reqx_lpx_trans_rpx (G) (L) (T:term):
+ ∀L1. L1 ≛[T] L → ∀L2. ❪G,L❫ ⊢ ⬈ L2 → ❪G,L❫ ⊢ ⬈[T] L2.
+/3 width=1 by lpx_rpx, reqx_rpx_trans/ qed.
+
+(* Basic_2A1: uses: lleq_lpx_trans *)
+lemma reqx_lpx_trans (G):
+ ∀L2,K2. ❪G,L2❫ ⊢ ⬈ K2 → ∀L1. ∀T:term. L1 ≛[T] L2 →
+ ∃∃K1. ❪G,L1❫ ⊢ ⬈ K1 & K1 ≛[T] K2.
+#G #L2 #K2 #HLK2 #L1 #T #HL12
+lapply (lpx_rpx … T … HLK2) -HLK2 #HLK2
+lapply (reqx_rpx_trans … HL12 … HLK2) -L2 #H
+elim (rpx_fwd_lpx_req … H) -H #K1 #HLK1 #HK12
+/3 width=3 by req_reqx, ex2_intro/
+qed-.
+
+(* Inversion lemmas with sort-irrelevant equivalence for local environments *)
+
+lemma rpx_inv_reqx_lpx (G) (T):
+ ∀L1,L2. ❪G,L1❫ ⊢ ⬈[T] L2 →
+ ∃∃L. L1 ≛[T] L & ❪G,L❫ ⊢ ⬈ L2.
+#G #T #L1 #L2 #H
+elim (rpx_inv_req_lpx … H) -H #L #HL1 #HL2
+/3 width=3 by req_reqx, ex2_intro/
+qed-.
+
+(* Forward lemmas with sort-irrelevant equivalence for local environments ***)
+
+lemma rpx_fwd_lpx_reqx (G) (T):
+ ∀L1,L2. ❪G,L1❫ ⊢ ⬈[T] L2 →
+ ∃∃L. ❪G,L1❫ ⊢ ⬈ L & L ≛[T] L2.
+#G #T #L1 #L2 #H
+elim (rpx_fwd_lpx_req … H) -H #L #HL1 #HL2
+/3 width=3 by req_reqx, ex2_intro/
+qed-.