--- /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/reqg_fqus.ma".
+include "basic_2/rt_transition/cpx_reqg.ma".
+include "basic_2/rt_transition/lpx_reqg.ma".
+include "basic_2/rt_transition/fpbc.ma".
+
+(* PROPER PARALLEL RST-TRANSITION FOR CLOSURES ******************************)
+
+(* Properties with generic equivalence for local environments ***************)
+
+(* Basic_2A1: was: teqg_fpb_trans *)
+lemma teqg_fpbc_trans (S):
+ reflexive … S → symmetric … S →
+ ∀U2,U1. U2 ≛[S] U1 →
+ ∀G1,G2,L1,L2,T1. ❪G1,L1,U1❫ ≻ ❪G2,L2,T1❫ →
+ ∃∃L,T2. ❪G1,L1,U2❫ ≻ ❪G2,L,T2❫ & T2 ≛[S] T1 & L ≛[S,T1] L2.
+#S #H1S #H2S #U2 #U1 #HU21 #G1 #G2 #L1 #L2 #T1 #H
+elim (fpbc_inv_gen S … H) -H #H12 #Hn12
+
+(* Basic_2A1: was just: lleq_fpb_trans *)
+lemma reqg_fpb_trans (S):
+ reflexive … S → symmetric … S →
+ ∀F,K1,K2,T. K1 ≛[S,T] K2 →
+ ∀G,L2,U. ❪F,K2,T❫ ≻ ❪G,L2,U❫ →
+ ∃∃L1,U0. ❪F,K1,T❫ ≻ ❪G,L1,U0❫ & U0 ≛[S] U & L1 ≛[S,U] L2.
+#S #H1S #H2S #F #K1 #K2 #T #HT #G #L2 #U * -G -L2 -U
+[ #G #L2 #U #H2 elim (reqg_fqu_trans … H2 … HT) -K2
+ /3 width=5 by fpb_fqu, ex3_2_intro/
+| #U #HTU #HnTU lapply (reqg_cpx_trans … HT … HTU) -HTU //
+ /4 width=8 by fpb_cpx, cpx_reqg_conf_sn, teqg_refl, ex3_2_intro/
+| #L2 #HKL2 #HnKL2 elim (reqg_lpx_trans … HKL2 … HT) -HKL2 //
+ /6 width=9 by fpb_lpx, reqg_reqx, reqg_repl, teqg_refl, ex3_2_intro/
+]
+qed-.