(* *)
(**************************************************************************)
+include "lambda-delta/substitution/lift_lift.ma".
include "lambda-delta/substitution/drop.ma".
(* DROPPING *****************************************************************)
(* Main properties **********************************************************)
-lemma drop_conf_ge: ∀d1,e1,L,L1. ↓[d1, e1] L ≡ L1 →
- ∀e2,L2. ↓[0, e2] L ≡ L2 → d1 + e1 ≤ e2 →
- ↓[0, e2 - e1] L1 ≡ L2.
+theorem drop_mono: ∀d,e,L,L1. ↓[d, e] L ≡ L1 →
+ ∀L2. ↓[d, e] L ≡ L2 → L1 = L2.
+#d #e #L #L1 #H elim H -H d e L L1
+[ #d #e #L2 #H
+ >(drop_inv_sort1 … H) -H L2 //
+| #K1 #K2 #I #V #HK12 #_ #L2 #HL12
+ <(drop_inv_refl … HK12) -HK12 K2
+ <(drop_inv_refl … HL12) -HL12 L2 //
+| #L #K #I #V #e #_ #IHLK #L2 #H
+ lapply (drop_inv_drop1 … H ?) -H /2/
+| #L #K1 #I #T #V1 #d #e #_ #HVT1 #IHLK1 #X #H
+ elim (drop_inv_skip1 … H ?) -H // <minus_plus_m_m #K2 #V2 #HLK2 #HVT2 #H destruct -X
+ >(lift_inj … HVT1 … HVT2) -HVT1 HVT2
+ >(IHLK1 … HLK2) -IHLK1 HLK2 //
+]
+qed.
+
+theorem drop_conf_ge: ∀d1,e1,L,L1. ↓[d1, e1] L ≡ L1 →
+ ∀e2,L2. ↓[0, e2] L ≡ L2 → d1 + e1 ≤ e2 →
+ ↓[0, e2 - e1] L1 ≡ L2.
#d1 #e1 #L #L1 #H elim H -H d1 e1 L L1
[ #d #e #e2 #L2 #H
>(drop_inv_sort1 … H) -H L2 //
| #L #K #I #V1 #V2 #d #e #_ #_ #IHLK #e2 #L2 #H #Hdee2
lapply (transitive_le 1 … Hdee2) // #He2
lapply (drop_inv_drop1 … H ?) -H // -He2 #HL2
- lapply (transitive_le (1+e) … Hdee2) // #Hee2
+ lapply (transitive_le (1 + e) … Hdee2) // #Hee2
@drop_drop_lt >minus_minus_comm /3/ (**) (* explicit constructor *)
]
qed.
-lemma drop_conf_lt: ∀d1,e1,L,L1. ↓[d1, e1] L ≡ L1 →
- ∀e2,K2,I,V2. ↓[0, e2] L ≡ K2. 𝕓{I} V2 →
- e2 < d1 → let d ≝ d1 - e2 - 1 in
- ∃∃K1,V1. ↓[0, e2] L1 ≡ K1. 𝕓{I} V1 &
- ↓[d, e1] K2 ≡ K1 & ↑[d, e1] V1 ≡ V2.
+theorem drop_conf_lt: ∀d1,e1,L,L1. ↓[d1, e1] L ≡ L1 →
+ ∀e2,K2,I,V2. ↓[0, e2] L ≡ K2. 𝕓{I} V2 →
+ e2 < d1 → let d ≝ d1 - e2 - 1 in
+ ∃∃K1,V1. ↓[0, e2] L1 ≡ K1. 𝕓{I} V1 &
+ ↓[d, e1] K2 ≡ K1 & ↑[d, e1] V1 ≡ V2.
#d1 #e1 #L #L1 #H elim H -H d1 e1 L L1
[ #d #e #e2 #K2 #I #V2 #H
lapply (drop_inv_sort1 … H) -H #H destruct
]
qed.
-lemma drop_trans_le: ∀d1,e1,L1,L. ↓[d1, e1] L1 ≡ L →
- ∀e2,L2. ↓[0, e2] L ≡ L2 → e2 ≤ d1 →
- ∃∃L0. ↓[0, e2] L1 ≡ L0 & ↓[d1 - e2, e1] L0 ≡ L2.
+theorem drop_trans_le: ∀d1,e1,L1,L. ↓[d1, e1] L1 ≡ L →
+ ∀e2,L2. ↓[0, e2] L ≡ L2 → e2 ≤ d1 →
+ ∃∃L0. ↓[0, e2] L1 ≡ L0 & ↓[d1 - e2, e1] L0 ≡ L2.
#d1 #e1 #L1 #L #H elim H -H d1 e1 L1 L
[ #d #e #e2 #L2 #H
>(drop_inv_sort1 … H) -H L2 /2/
]
qed.
-lemma drop_trans_ge: ∀d1,e1,L1,L. ↓[d1, e1] L1 ≡ L →
- ∀e2,L2. ↓[0, e2] L ≡ L2 → d1 ≤ e2 → ↓[0, e1 + e2] L1 ≡ L2.
+theorem drop_trans_ge: ∀d1,e1,L1,L. ↓[d1, e1] L1 ≡ L →
+ ∀e2,L2. ↓[0, e2] L ≡ L2 → d1 ≤ e2 → ↓[0, e1 + e2] L1 ≡ L2.
#d1 #e1 #L1 #L #H elim H -H d1 e1 L1 L
[ #d #e #e2 #L2 #H
>(drop_inv_sort1 … H) -H L2 //
]
qed.
-lemma drop_trans_ge_comm: ∀d1,e1,e2,L1,L2,L.
- ↓[d1, e1] L1 ≡ L → ↓[0, e2] L ≡ L2 → d1 ≤ e2 →
- ↓[0, e2 + e1] L1 ≡ L2.
+theorem drop_trans_ge_comm: ∀d1,e1,e2,L1,L2,L.
+ ↓[d1, e1] L1 ≡ L → ↓[0, e2] L ≡ L2 → d1 ≤ e2 →
+ ↓[0, e2 + e1] L1 ≡ L2.
#e1 #e1 #e2 >commutative_plus /2 width=5/
qed.