--- /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/relocation/drops.ma".
+include "basic_2/rt_computation/jsx.ma".
+
+(* COMPATIBILITY OF STRONG NORMALIZATION FOR UNBOUND RT-TRANSITION **********)
+
+(* Forward lemmas with uniform slicing for local environments ***************)
+
+lemma jsx_fwd_drops_atom_sn (h) (b) (G):
+ ∀L1,L2. G ⊢ L1 ⊒[h] L2 →
+ ∀f. 𝐔⦃f⦄ → ⬇*[b,f]L1 ≘ ⋆ → ⬇*[b,f]L2 ≘ ⋆.
+#h #b #G #L1 #L2 #H elim H -L1 -L2
+[ #f #_ #H //
+| #I #K1 #K2 #_ #IH #f #Hf #H
+| #I #K1 #K2 #V #_ #HV #IH #f #Hf #H
+]
+elim (drops_inv_bind1_isuni … H) -H [3,6: // |*: * -Hf ]
+[1,3: #_ #H destruct
+|2,4: #g #Hg #HK1 #H destruct /3 width=1 by drops_drop/
+]
+qed-.
+
+lemma jsx_fwd_drops_unit_sn (h) (b) (G):
+ ∀L1,L2. G ⊢ L1 ⊒[h] L2 →
+ ∀f. 𝐔⦃f⦄ → ∀I,K1. ⬇*[b,f]L1 ≘ K1.ⓤ{I} →
+ ∃∃K2. G ⊢ K1 ⊒[h] K2 & ⬇*[b,f]L2 ≘ K2.ⓤ{I}.
+#h #b #G #L1 #L2 #H elim H -L1 -L2
+[ #f #_ #J #Y1 #H
+ lapply (drops_inv_atom1 … H) -H * #H #_ destruct
+| #I #K1 #K2 #HK12 #IH #f #Hf #J #Y1 #H
+| #I #K1 #K2 #V #HK12 #HV #IH #f #Hf #J #Y1 #H
+]
+elim (drops_inv_bind1_isuni … H) -H [3,6: // |*: * -Hf ]
+[1,3: #Hf #H destruct -IH /3 width=3 by drops_refl, ex2_intro/
+|2,4:
+ #g #Hg #HK1 #H destruct
+ elim (IH … Hg … HK1) -K1 -Hg #Y2 #HY12 #HKY2
+ /3 width=3 by drops_drop, ex2_intro/
+]
+qed-.
+
+lemma jsx_fwd_drops_pair_sn (h) (b) (G):
+ ∀L1,L2. G ⊢ L1 ⊒[h] L2 →
+ ∀f. 𝐔⦃f⦄ → ∀I,K1,V. ⬇*[b,f]L1 ≘ K1.ⓑ{I}V →
+ ∨∨ ∃∃K2. G ⊢ K1 ⊒[h] K2 & ⬇*[b,f]L2 ≘ K2.ⓑ{I}V
+ | ∃∃K2. G ⊢ K1 ⊒[h] K2 & ⬇*[b,f]L2 ≘ K2.ⓧ & G ⊢ ⬈*[h,V] 𝐒⦃K2⦄.
+#h #b #G #L1 #L2 #H elim H -L1 -L2
+[ #f #_ #J #Y1 #X1 #H
+ lapply (drops_inv_atom1 … H) -H * #H #_ destruct
+| #I #K1 #K2 #HK12 #IH #f #Hf #J #Y1 #X1 #H
+| #I #K1 #K2 #V #HK12 #HV #IH #f #Hf #J #Y1 #X1 #H
+]
+elim (drops_inv_bind1_isuni … H) -H [3,6: // |*: * -Hf ]
+[1,3:
+ #Hf #H destruct -IH
+ /4 width=4 by drops_refl, ex3_intro, ex2_intro, or_introl, or_intror/
+|2,4:
+ #g #Hg #HK1 #H destruct
+ elim (IH … Hg … HK1) -K1 -Hg * #Y2 #HY12 #HKY2 [2,4: #HX1 ]
+ /4 width=4 by drops_drop, ex3_intro, ex2_intro, or_introl, or_intror/
+]
+qed-.