--- /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/rt_transition/rpx_lpx.ma".
+include "basic_2/rt_transition/fpb.ma".
+
+(* PARALLEL RST-TRANSITION FOR CLOSURES *************************************)
+
+(* Properties with extended rt-transition for full local envs ***************)
+
+(* Basic_2A1: uses: fpbq_lpx *)
+lemma lpx_fpb (G) (T):
+ ∀L1,L2. ❪G,L1❫ ⊢ ⬈ L2 → ❪G,L1,T❫ ≽ ❪G,L2,T❫.
+/3 width=1 by rpx_fpb, lpx_rpx/ qed.
+
+lemma fpb_intro_req (G1) (G2) (L1) (L2) (T1) (T2):
+ ∀L0,L,T. ❪G1,L1,T1❫ ⬂⸮ ❪G2,L,T❫ → ❪G2,L❫ ⊢ T ⬈ T2 →
+ L ≡[T] L0 → ❪G2,L0❫ ⊢ ⬈ L2 → ❪G1,L1,T1❫ ≽ ❪G2,L2,T2❫.
+/4 width=10 by fpb_intro, lpx_rpx, reqg_rpx_trans/ qed.
+
+(* Inversion lemmas with extended rt-transition for full local envs *********)
+
+lemma fpb_inv_req (G1) (G2) (L1) (L2) (T1) (T2):
+ ❪G1,L1,T1❫ ≽ ❪G2,L2,T2❫ →
+ ∃∃L0,L,T. ❪G1,L1,T1❫ ⬂⸮ ❪G2,L,T❫ & ❪G2,L❫ ⊢ T ⬈ T2 & L ≡[T] L0 & ❪G2,L0❫ ⊢ ⬈ L2.
+#G1 #G2 #L1 #L2 #T1 #T2 * #L #T #H1 #HT2 #HL2
+elim (rpx_inv_req_lpx … HL2) -HL2 #L0 #HL0 #HL02
+/2 width=7 by ex4_3_intro/
+qed-.
+
+(* Forward lemmas with extended rt-transition for full local envs ***********)
+
+lemma fpb_fwd_req (G1) (G2) (L1) (L2) (T1) (T2):
+ ❪G1,L1,T1❫ ≽ ❪G2,L2,T2❫ →
+ ∃∃L0,L,T. ❪G1,L1,T1❫ ⬂⸮ ❪G2,L,T❫ & ❪G2,L❫ ⊢ T ⬈ T2 & ❪G2,L❫ ⊢ ⬈ L0 & L0 ≡[T] L2.
+#G1 #G2 #L1 #L2 #T1 #T2 * #L #T #H1 #HT2 #HL2
+elim (rpx_fwd_lpx_req … HL2) -HL2 #L0 #HL0 #HL02
+/2 width=7 by ex4_3_intro/
+qed-.