--- /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 "static_2/static/lsubr.ma".
+
+(* RESTRICTED REFINEMENT FOR LOCAL ENVIRONMENTS *****************************)
+
+(* Forward lemmas with generic slicing for local environments ***************)
+
+(* Basic_2A1: includes: lsubr_fwd_drop2_pair *)
+lemma lsubr_fwd_drops2_bind: âL1,L2. L1 ⍠L2 â
+ âb,f,I,K2. đâŚf⌠â âŹ*[b, f] L2 â K2.â{I} â
+ â¨â¨ ââK1. K1 ⍠K2 & âŹ*[b, f] L1 â K1.â{I}
+ | ââK1,W,V. K1 ⍠K2 & âŹ*[b, f] L1 â K1.ââW.V & I = BPair Abst W
+ | ââJ1,J2,K1,V. K1 ⍠K2 & âŹ*[b, f] L1 â K1.â{J1}V & I = BUnit J2.
+#L1 #L2 #H elim H -L1 -L2
+[ #b #f #I #K2 #_ #H
+ elim (drops_inv_atom1 ⌠H) -H #H destruct
+| #J #L1 #L2 | #L1 #L2 #V #W | #I1 #I2 #L1 #L2 #V1
+]
+#HL12 #IH #b #f #I #K2 #Hf #H
+elim (drops_inv_bind1_isuni ⌠Hf H) -Hf -H *
+[1,3,5: #Hf #H destruct -IH
+ /4 width=6 by drops_refl, or3_intro0, or3_intro1, or3_intro2, ex3_4_intro, ex3_3_intro, ex2_intro/
+|2,4,6: #g #Hg #HLK2 #H destruct -HL12
+ elim (IH ⌠Hg HLK2) -IH -Hg -HLK2 *
+ /4 width=6 by drops_drop, or3_intro0, or3_intro1, or3_intro2, ex3_4_intro, ex3_3_intro, ex2_intro/
+]
+qed-.
+
+(* Basic_2A1: includes: lsubr_fwd_drop2_abbr *)
+lemma lsubr_fwd_drops2_abbr: âL1,L2. L1 ⍠L2 â
+ âb,f,K2,V. đâŚf⌠â âŹ*[b, f] L2 â K2.âV â
+ ââK1. K1 ⍠K2 & âŹ*[b, f] L1 â K1.âV.
+#L1 #L2 #HL12 #b #f #K2 #V #Hf #HLK2
+elim (lsubr_fwd_drops2_bind ⌠HL12 ⌠Hf HLK2) -L2 -Hf // *
+[ #K1 #W #V #_ #_ #H destruct
+| #I1 #I2 #K1 #V #_ #_ #H destruct
+]
+qed-.