include "basic_2/unfold/tpss.ma".
-(* DELIFT ON TERMS **********************************************************)
+(* INVERSE BASIC TERM RELOCATION *******************************************)
definition delift: nat → nat → lenv → relation term ≝
- λd,e,L,T1,T2. ∃∃T. L ⊢ T1 [d, e] ▶* T & ⇧[d, e] T2 ≡ T.
+ λd,e,L,T1,T2. ∃∃T. L ⊢ T1 ▶* [d, e] T & ⇧[d, e] T2 ≡ T.
-interpretation "delift (term)"
+interpretation "inverse basic relocation (term)"
'TSubst L T1 d e T2 = (delift d e L T1 T2).
(* Basic properties *********************************************************)
+lemma lift_delift: ∀T1,T2,d,e. ⇧[d, e] T1 ≡ T2 →
+ ∀L. L ⊢ T2 [d, e] ≡ T1.
+/2 width=3/ qed.
+
+lemma delift_refl_O2: ∀L,T,d. L ⊢ T [d, 0] ≡ T.
+/2 width=3/ qed.
+
lemma delift_lsubs_conf: ∀L1,T1,T2,d,e. L1 ⊢ T1 [d, e] ≡ T2 →
- ∀L2. L1 [d, e] ≼ L2 → L2 ⊢ T1 [d, e] ≡ T2.
+ ∀L2. L1 ≼ [d, e] L2 → L2 ⊢ T1 [d, e] ≡ T2.
#L1 #T1 #T2 #d #e * /3 width=3/
qed.
+lemma delift_sort: ∀L,d,e,k. L ⊢ ⋆k [d, e] ≡ ⋆k.
+/2 width=3/ qed.
+
+lemma delift_lref_lt: ∀L,d,e,i. i < d → L ⊢ #i [d, e] ≡ #i.
+/3 width=3/ qed.
+
+lemma delift_lref_ge: ∀L,d,e,i. d + e ≤ i → L ⊢ #i [d, e] ≡ #(i - e).
+/3 width=3/ qed.
+
+lemma delift_gref: ∀L,d,e,p. L ⊢ §p [d, e] ≡ §p.
+/2 width=3/ qed.
+
lemma delift_bind: ∀I,L,V1,V2,T1,T2,d,e.
L ⊢ V1 [d, e] ≡ V2 → L. ⓑ{I} V2 ⊢ T1 [d+1, e] ≡ T2 →
L ⊢ ⓑ{I} V1. T1 [d, e] ≡ ⓑ{I} V2. T2.
#I #L #V1 #V2 #T1 #T2 #d #e * #V #HV1 #HV2 * /3 width=5/
qed.
-(* Basic forward lemmas *****************************************************)
+(* Basic inversion lemmas ***************************************************)
-lemma delift_fwd_sort1: ∀L,U2,d,e,k. L ⊢ ⋆k [d, e] ≡ U2 → U2 = ⋆k.
+lemma delift_inv_sort1: ∀L,U2,d,e,k. L ⊢ ⋆k [d, e] ≡ U2 → U2 = ⋆k.
#L #U2 #d #e #k * #U #HU
>(tpss_inv_sort1 … HU) -HU #HU2
>(lift_inv_sort2 … HU2) -HU2 //
qed-.
-lemma delift_fwd_gref1: ∀L,U2,d,e,p. L ⊢ §p [d, e] ≡ U2 → U2 = §p.
+lemma delift_inv_gref1: ∀L,U2,d,e,p. L ⊢ §p [d, e] ≡ U2 → U2 = §p.
#L #U #d #e #p * #U #HU
>(tpss_inv_gref1 … HU) -HU #HU2
>(lift_inv_gref2 … HU2) -HU2 //
qed-.
-lemma delift_fwd_bind1: ∀I,L,V1,T1,U2,d,e. L ⊢ ⓑ{I} V1. T1 [d, e] ≡ U2 →
+lemma delift_inv_bind1: ∀I,L,V1,T1,U2,d,e. L ⊢ ⓑ{I} V1. T1 [d, e] ≡ U2 →
∃∃V2,T2. L ⊢ V1 [d, e] ≡ V2 &
L. ⓑ{I} V2 ⊢ T1 [d+1, e] ≡ T2 &
U2 = ⓑ{I} V2. T2.
lapply (tpss_lsubs_conf … HT1 (L. ⓑ{I} V2) ?) -HT1 /2 width=1/ /3 width=5/
qed-.
-lemma delift_fwd_flat1: ∀I,L,V1,T1,U2,d,e. L ⊢ ⓕ{I} V1. T1 [d, e] ≡ U2 →
+lemma delift_inv_flat1: ∀I,L,V1,T1,U2,d,e. L ⊢ ⓕ{I} V1. T1 [d, e] ≡ U2 →
∃∃V2,T2. L ⊢ V1 [d, e] ≡ V2 &
L ⊢ T1 [d, e] ≡ T2 &
U2 = ⓕ{I} V2. T2.
elim (lift_inv_flat2 … HU2) -HU2 /3 width=5/
qed-.
-(* Basic Inversion lemmas ***************************************************)
-
lemma delift_inv_refl_O2: ∀L,T1,T2,d. L ⊢ T1 [d, 0] ≡ T2 → T1 = T2.
#L #T1 #T2 #d * #T #HT1
>(tpss_inv_refl_O2 … HT1) -HT1 #HT2