--- /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/substitution/ltps.ma".
+
+(* PARALLEL SUBSTITUTION ON LOCAL ENVIRONMENTS ******************************)
+
+lemma ltps_drop_conf_ge: ∀L0,L1,d1,e1. L0 [d1, e1] ≫ L1 →
+ ∀L2,e2. ↓[0, e2] L0 ≡ L2 →
+ d1 + e1 ≤ e2 → ↓[0, e2] L1 ≡ L2.
+#L0 #L1 #d1 #e1 #H elim H -H L0 L1 d1 e1
+[ #d1 #e1 #L2 #e2 #H >(drop_inv_atom1 … H) -H //
+| //
+| normalize #K0 #K1 #I #V0 #V1 #e1 #_ #_ #IHK01 #L2 #e2 #H #He12
+ lapply (plus_le_weak … He12) #He2
+ lapply (drop_inv_drop1 … H ?) -H // #HK0L2
+ lapply (IHK01 … HK0L2 ?) -IHK01 HK0L2 /2/
+| #K0 #K1 #I #V0 #V1 #d1 #e1 >plus_plus_comm_23 #_ #_ #IHK01 #L2 #e2 #H #Hd1e2
+ lapply (plus_le_weak … Hd1e2) #He2
+ lapply (drop_inv_drop1 … H ?) -H // #HK0L2
+ lapply (IHK01 … HK0L2 ?) -IHK01 HK0L2 /2/
+]
+qed.
+
+lemma ltps_drop_trans_ge: ∀L1,L0,d1,e1. L1 [d1, e1] ≫ L0 →
+ ∀L2,e2. ↓[0, e2] L0 ≡ L2 →
+ d1 + e1 ≤ e2 → ↓[0, e2] L1 ≡ L2.
+#L1 #L0 #d1 #e1 #H elim H -H L1 L0 d1 e1
+[ #d1 #e1 #L2 #e2 #H >(drop_inv_atom1 … H) -H //
+| //
+| normalize #K1 #K0 #I #V1 #V0 #e1 #_ #_ #IHK10 #L2 #e2 #H #He12
+ lapply (plus_le_weak … He12) #He2
+ lapply (drop_inv_drop1 … H ?) -H // #HK0L2
+ lapply (IHK10 … HK0L2 ?) -IHK10 HK0L2 /2/
+| #K0 #K1 #I #V1 #V0 #d1 #e1 >plus_plus_comm_23 #_ #_ #IHK10 #L2 #e2 #H #Hd1e2
+ lapply (plus_le_weak … Hd1e2) #He2
+ lapply (drop_inv_drop1 … H ?) -H // #HK0L2
+ lapply (IHK10 … HK0L2 ?) -IHK10 HK0L2 /2/
+]
+qed.
+
+lemma ltps_drop_conf_be: ∀L0,L1,d1,e1. L0 [d1, e1] ≫ L1 →
+ ∀L2,e2. ↓[0, e2] L0 ≡ L2 → d1 ≤ e2 → e2 ≤ d1 + e1 →
+ ∃∃L. L2 [0, d1 + e1 - e2] ≫ L & ↓[0, e2] L1 ≡ L.
+#L0 #L1 #d1 #e1 #H elim H -H L0 L1 d1 e1
+[ #d1 #e1 #L2 #e2 #H >(drop_inv_atom1 … H) -H /2/
+| normalize #L #I #V #L2 #e2 #HL2 #_ #He2
+ lapply (le_n_O_to_eq … He2) -He2 #H destruct -e2;
+ lapply (drop_inv_refl … HL2) -HL2 #H destruct -L2 /2/
+| normalize #K0 #K1 #I #V0 #V1 #e1 #HK01 #HV01 #IHK01 #L2 #e2 #H #_ #He21
+ lapply (drop_inv_O1 … H) -H * * #He2 #HK0L2
+ [ destruct -IHK01 He21 e2 L2 <minus_n_O /3/
+ | -HK01 HV01 <minus_le_minus_minus_comm //
+ elim (IHK01 … HK0L2 ? ?) -IHK01 HK0L2 /3/
+ ]
+| #K0 #K1 #I #V0 #V1 #d1 #e1 >plus_plus_comm_23 #_ #_ #IHK01 #L2 #e2 #H #Hd1e2 #He2de1
+ lapply (plus_le_weak … Hd1e2) #He2
+ <minus_le_minus_minus_comm //
+ lapply (drop_inv_drop1 … H ?) -H // #HK0L2
+ elim (IHK01 … HK0L2 ? ?) -IHK01 HK0L2 /3/
+]
+qed.
+
+lemma ltps_drop_trans_be: ∀L1,L0,d1,e1. L1 [d1, e1] ≫ L0 →
+ ∀L2,e2. ↓[0, e2] L0 ≡ L2 → d1 ≤ e2 → e2 ≤ d1 + e1 →
+ ∃∃L. L [0, d1 + e1 - e2] ≫ L2 & ↓[0, e2] L1 ≡ L.
+#L1 #L0 #d1 #e1 #H elim H -H L1 L0 d1 e1
+[ #d1 #e1 #L2 #e2 #H >(drop_inv_atom1 … H) -H /2/
+| normalize #L #I #V #L2 #e2 #HL2 #_ #He2
+ lapply (le_n_O_to_eq … He2) -He2 #H destruct -e2;
+ lapply (drop_inv_refl … HL2) -HL2 #H destruct -L2 /2/
+| normalize #K1 #K0 #I #V1 #V0 #e1 #HK10 #HV10 #IHK10 #L2 #e2 #H #_ #He21
+ lapply (drop_inv_O1 … H) -H * * #He2 #HK0L2
+ [ destruct -IHK10 He21 e2 L2 <minus_n_O /3/
+ | -HK10 HV10 <minus_le_minus_minus_comm //
+ elim (IHK10 … HK0L2 ? ?) -IHK10 HK0L2 /3/
+ ]
+| #K1 #K0 #I #V1 #V0 #d1 #e1 >plus_plus_comm_23 #_ #_ #IHK10 #L2 #e2 #H #Hd1e2 #He2de1
+ lapply (plus_le_weak … Hd1e2) #He2
+ <minus_le_minus_minus_comm //
+ lapply (drop_inv_drop1 … H ?) -H // #HK0L2
+ elim (IHK10 … HK0L2 ? ?) -IHK10 HK0L2 /3/
+]
+qed.
+
+lemma ltps_drop_conf_le: ∀L0,L1,d1,e1. L0 [d1, e1] ≫ L1 →
+ ∀L2,e2. ↓[0, e2] L0 ≡ L2 → e2 ≤ d1 →
+ ∃∃L. L2 [d1 - e2, e1] ≫ L & ↓[0, e2] L1 ≡ L.
+#L0 #L1 #d1 #e1 #H elim H -H L0 L1 d1 e1
+[ #d1 #e1 #L2 #e2 #H >(drop_inv_atom1 … H) -H /2/
+| /2/
+| normalize #K0 #K1 #I #V0 #V1 #e1 #HK01 #HV01 #_ #L2 #e2 #H #He2
+ lapply (le_n_O_to_eq … He2) -He2 #He2 destruct -e2;
+ lapply (drop_inv_refl … H) -H #H destruct -L2 /3/
+| #K0 #K1 #I #V0 #V1 #d1 #e1 #HK01 #HV01 #IHK01 #L2 #e2 #H #He2d1
+ lapply (drop_inv_O1 … H) -H * * #He2 #HK0L2
+ [ destruct -IHK01 He2d1 e2 L2 <minus_n_O /3/
+ | -HK01 HV01 <minus_le_minus_minus_comm //
+ elim (IHK01 … HK0L2 ?) -IHK01 HK0L2 /3/
+ ]
+]
+qed.
+
+lemma ltps_drop_trans_le: ∀L1,L0,d1,e1. L1 [d1, e1] ≫ L0 →
+ ∀L2,e2. ↓[0, e2] L0 ≡ L2 → e2 ≤ d1 →
+ ∃∃L. L [d1 - e2, e1] ≫ L2 & ↓[0, e2] L1 ≡ L.
+#L1 #L0 #d1 #e1 #H elim H -H L1 L0 d1 e1
+[ #d1 #e1 #L2 #e2 #H >(drop_inv_atom1 … H) -H /2/
+| /2/
+| normalize #K1 #K0 #I #V1 #V0 #e1 #HK10 #HV10 #_ #L2 #e2 #H #He2
+ lapply (le_n_O_to_eq … He2) -He2 #He2 destruct -e2;
+ lapply (drop_inv_refl … H) -H #H destruct -L2 /3/
+| #K1 #K0 #I #V1 #V0 #d1 #e1 #HK10 #HV10 #IHK10 #L2 #e2 #H #He2d1
+ lapply (drop_inv_O1 … H) -H * * #He2 #HK0L2
+ [ destruct -IHK10 He2d1 e2 L2 <minus_n_O /3/
+ | -HK10 HV10 <minus_le_minus_minus_comm //
+ elim (IHK10 … HK0L2 ?) -IHK10 HK0L2 /3/
+ ]
+]
+qed.
+*)