--- /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 "ground_2/relocation/trace_isid.ma".
+include "basic_2/notation/relations/rliftstar_3.ma".
+include "basic_2/grammar/term.ma".
+
+(* GENERIC TERM RELOCATION **************************************************)
+
+(* Basic_1: includes:
+ lift_sort lift_lref_lt lift_lref_ge lift_bind lift_flat
+ lifts_nil lifts_cons
+*)
+inductive lifts: trace → relation term ≝
+| lifts_sort: ∀k,t. lifts t (⋆k) (⋆k)
+| lifts_lref: ∀i1,i2,t. @⦃i1, t⦄ ≡ i2 → lifts t (#i1) (#i2)
+| lifts_gref: ∀p,t. lifts t (§p) (§p)
+| lifts_bind: ∀a,I,V1,V2,T1,T2,t.
+ lifts t V1 V2 → lifts (Ⓣ@t) T1 T2 →
+ lifts t (ⓑ{a,I}V1.T1) (ⓑ{a,I}V2.T2)
+| lifts_flat: ∀I,V1,V2,T1,T2,t.
+ lifts t V1 V2 → lifts t T1 T2 →
+ lifts t (ⓕ{I}V1.T1) (ⓕ{I}V2.T2)
+.
+
+interpretation "generic relocation (term)"
+ 'RLiftStar cs T1 T2 = (lifts cs T1 T2).
+
+(* Basic inversion lemmas ***************************************************)
+
+fact lifts_inv_sort1_aux: ∀X,Y,t. ⬆*[t] X ≡ Y → ∀k. X = ⋆k → Y = ⋆k.
+#X #Y #t * -X -Y -t //
+[ #i1 #i2 #t #_ #x #H destruct
+| #a #I #V1 #V2 #T1 #T2 #t #_ #_ #x #H destruct
+| #I #V1 #V2 #T1 #T2 #t #_ #_ #x #H destruct
+]
+qed-.
+
+(* Basic_1: was: lift1_sort *)
+(* Basic_2A1: includes: lift_inv_sort1 *)
+lemma lifts_inv_sort1: ∀Y,k,t. ⬆*[t] ⋆k ≡ Y → Y = ⋆k.
+/2 width=4 by lifts_inv_sort1_aux/ qed-.
+
+fact lifts_inv_lref1_aux: ∀X,Y,t. ⬆*[t] X ≡ Y → ∀i1. X = #i1 →
+ ∃∃i2. @⦃i1, t⦄ ≡ i2 & Y = #i2.
+#X #Y #t * -X -Y -t
+[ #k #t #x #H destruct
+| #i1 #i2 #t #Hi12 #x #H destruct /2 width=3 by ex2_intro/
+| #p #t #x #H destruct
+| #a #I #V1 #V2 #T1 #T2 #t #_ #_ #x #H destruct
+| #I #V1 #V2 #T1 #T2 #t #_ #_ #x #H destruct
+]
+qed-.
+
+(* Basic_1: was: lift1_lref *)
+(* Basic_2A1: includes: lift_inv_lref1 lift_inv_lref1_lt lift_inv_lref1_ge *)
+lemma lifts_inv_lref1: ∀Y,i1,t. ⬆*[t] #i1 ≡ Y →
+ ∃∃i2. @⦃i1, t⦄ ≡ i2 & Y = #i2.
+/2 width=3 by lifts_inv_lref1_aux/ qed-.
+
+fact lifts_inv_gref1_aux: ∀X,Y,t. ⬆*[t] X ≡ Y → ∀p. X = §p → Y = §p.
+#X #Y #t * -X -Y -t //
+[ #i1 #i2 #t #_ #x #H destruct
+| #a #I #V1 #V2 #T1 #T2 #t #_ #_ #x #H destruct
+| #I #V1 #V2 #T1 #T2 #t #_ #_ #x #H destruct
+]
+qed-.
+
+(* Basic_2A1: includes: lift_inv_gref1 *)
+lemma lifts_inv_gref1: ∀Y,p,t. ⬆*[t] §p ≡ Y → Y = §p.
+/2 width=4 by lifts_inv_gref1_aux/ qed-.
+
+fact lifts_inv_bind1_aux: ∀X,Y,t. ⬆*[t] X ≡ Y →
+ ∀a,I,V1,T1. X = ⓑ{a,I}V1.T1 →
+ ∃∃V2,T2. ⬆*[t] V1 ≡ V2 & ⬆*[Ⓣ@t] T1 ≡ T2 &
+ Y = ⓑ{a,I}V2.T2.
+#X #Y #t * -X -Y -t
+[ #k #t #b #J #W1 #U1 #H destruct
+| #i1 #i2 #t #_ #b #J #W1 #U1 #H destruct
+| #p #t #b #J #W1 #U1 #H destruct
+| #a #I #V1 #V2 #T1 #T2 #t #HV12 #HT12 #b #J #W1 #U1 #H destruct /2 width=5 by ex3_2_intro/
+| #I #V1 #V2 #T1 #T2 #t #_ #_ #b #J #W1 #U1 #H destruct
+]
+qed-.
+
+(* Basic_1: was: lift1_bind *)
+(* Basic_2A1: includes: lift_inv_bind1 *)
+lemma lifts_inv_bind1: ∀a,I,V1,T1,Y,t. ⬆*[t] ⓑ{a,I}V1.T1 ≡ Y →
+ ∃∃V2,T2. ⬆*[t] V1 ≡ V2 & ⬆*[Ⓣ@t] T1 ≡ T2 &
+ Y = ⓑ{a,I}V2.T2.
+/2 width=3 by lifts_inv_bind1_aux/ qed-.
+
+fact lifts_inv_flat1_aux: ∀X,Y,t. ⬆*[t] X ≡ Y →
+ ∀I,V1,T1. X = ⓕ{I}V1.T1 →
+ ∃∃V2,T2. ⬆*[t] V1 ≡ V2 & ⬆*[t] T1 ≡ T2 &
+ Y = ⓕ{I}V2.T2.
+#X #Y #t * -X -Y -t
+[ #k #t #J #W1 #U1 #H destruct
+| #i1 #i2 #t #_ #J #W1 #U1 #H destruct
+| #p #t #J #W1 #U1 #H destruct
+| #a #I #V1 #V2 #T1 #T2 #t #_ #_ #J #W1 #U1 #H destruct
+| #I #V1 #V2 #T1 #T2 #t #HV12 #HT12 #J #W1 #U1 #H destruct /2 width=5 by ex3_2_intro/
+]
+qed-.
+
+(* Basic_1: was: lift1_flat *)
+(* Basic_2A1: includes: lift_inv_flat1 *)
+lemma lifts_inv_flat1: ∀I,V1,T1,Y,t. ⬆*[t] ⓕ{I}V1.T1 ≡ Y →
+ ∃∃V2,T2. ⬆*[t] V1 ≡ V2 & ⬆*[t] T1 ≡ T2 &
+ Y = ⓕ{I}V2.T2.
+/2 width=3 by lifts_inv_flat1_aux/ qed-.
+
+fact lifts_inv_sort2_aux: ∀X,Y,t. ⬆*[t] X ≡ Y → ∀k. Y = ⋆k → X = ⋆k.
+#X #Y #t * -X -Y -t //
+[ #i1 #i2 #t #_ #x #H destruct
+| #a #I #V1 #V2 #T1 #T2 #t #_ #_ #x #H destruct
+| #I #V1 #V2 #T1 #T2 #t #_ #_ #x #H destruct
+]
+qed-.
+
+(* Basic_1: includes: lift_gen_sort *)
+(* Basic_2A1: includes: lift_inv_sort2 *)
+lemma lifts_inv_sort2: ∀X,k,t. ⬆*[t] X ≡ ⋆k → X = ⋆k.
+/2 width=4 by lifts_inv_sort2_aux/ qed-.
+
+fact lifts_inv_lref2_aux: ∀X,Y,t. ⬆*[t] X ≡ Y → ∀i2. Y = #i2 →
+ ∃∃i1. @⦃i1, t⦄ ≡ i2 & X = #i1.
+#X #Y #t * -X -Y -t
+[ #k #t #x #H destruct
+| #i1 #i2 #t #Hi12 #x #H destruct /2 width=3 by ex2_intro/
+| #p #t #x #H destruct
+| #a #I #V1 #V2 #T1 #T2 #t #_ #_ #x #H destruct
+| #I #V1 #V2 #T1 #T2 #t #_ #_ #x #H destruct
+]
+qed-.
+
+(* Basic_1: includes: lift_gen_lref lift_gen_lref_lt lift_gen_lref_false lift_gen_lref_ge *)
+(* Basic_2A1: includes: lift_inv_lref2 lift_inv_lref2_lt lift_inv_lref2_be lift_inv_lref2_ge lift_inv_lref2_plus *)
+lemma lifts_inv_lref2: ∀X,i2,t. ⬆*[t] X ≡ #i2 →
+ ∃∃i1. @⦃i1, t⦄ ≡ i2 & X = #i1.
+/2 width=3 by lifts_inv_lref2_aux/ qed-.
+
+fact lifts_inv_gref2_aux: ∀X,Y,t. ⬆*[t] X ≡ Y → ∀p. Y = §p → X = §p.
+#X #Y #t * -X -Y -t //
+[ #i1 #i2 #t #_ #x #H destruct
+| #a #I #V1 #V2 #T1 #T2 #t #_ #_ #x #H destruct
+| #I #V1 #V2 #T1 #T2 #t #_ #_ #x #H destruct
+]
+qed-.
+
+(* Basic_2A1: includes: lift_inv_gref1 *)
+lemma lifts_inv_gref2: ∀X,p,t. ⬆*[t] X ≡ §p → X = §p.
+/2 width=4 by lifts_inv_gref2_aux/ qed-.
+
+fact lifts_inv_bind2_aux: ∀X,Y,t. ⬆*[t] X ≡ Y →
+ ∀a,I,V2,T2. Y = ⓑ{a,I}V2.T2 →
+ ∃∃V1,T1. ⬆*[t] V1 ≡ V2 & ⬆*[Ⓣ@t] T1 ≡ T2 &
+ X = ⓑ{a,I}V1.T1.
+#X #Y #t * -X -Y -t
+[ #k #t #b #J #W2 #U2 #H destruct
+| #i1 #i2 #t #_ #b #J #W2 #U2 #H destruct
+| #p #t #b #J #W2 #U2 #H destruct
+| #a #I #V1 #V2 #T1 #T2 #t #HV12 #HT12 #b #J #W2 #U2 #H destruct /2 width=5 by ex3_2_intro/
+| #I #V1 #V2 #T1 #T2 #t #_ #_ #b #J #W2 #U2 #H destruct
+]
+qed-.
+
+(* Basic_1: includes: lift_gen_bind *)
+(* Basic_2A1: includes: lift_inv_bind2 *)
+lemma lifts_inv_bind2: ∀a,I,V2,T2,X,t. ⬆*[t] X ≡ ⓑ{a,I}V2.T2 →
+ ∃∃V1,T1. ⬆*[t] V1 ≡ V2 & ⬆*[Ⓣ@t] T1 ≡ T2 &
+ X = ⓑ{a,I}V1.T1.
+/2 width=3 by lifts_inv_bind2_aux/ qed-.
+
+fact lifts_inv_flat2_aux: ∀X,Y,t. ⬆*[t] X ≡ Y →
+ ∀I,V2,T2. Y = ⓕ{I}V2.T2 →
+ ∃∃V1,T1. ⬆*[t] V1 ≡ V2 & ⬆*[t] T1 ≡ T2 &
+ X = ⓕ{I}V1.T1.
+#X #Y #t * -X -Y -t
+[ #k #t #J #W2 #U2 #H destruct
+| #i1 #i2 #t #_ #J #W2 #U2 #H destruct
+| #p #t #J #W2 #U2 #H destruct
+| #a #I #V1 #V2 #T1 #T2 #t #_ #_ #J #W2 #U2 #H destruct
+| #I #V1 #V2 #T1 #T2 #t #HV12 #HT12 #J #W2 #U2 #H destruct /2 width=5 by ex3_2_intro/
+]
+qed-.
+
+(* Basic_1: includes: lift_gen_flat *)
+(* Basic_2A1: includes: lift_inv_flat2 *)
+lemma lifts_inv_flat2: ∀I,V2,T2,X,t. ⬆*[t] X ≡ ⓕ{I}V2.T2 →
+ ∃∃V1,T1. ⬆*[t] V1 ≡ V2 & ⬆*[t] T1 ≡ T2 &
+ X = ⓕ{I}V1.T1.
+/2 width=3 by lifts_inv_flat2_aux/ qed-.
+
+(* Basic_2A1: includes: lift_inv_pair_xy_x *)
+lemma lifts_inv_pair_xy_x: ∀I,V,T,t. ⬆*[t] ②{I}V.T ≡ V → ⊥.
+#J #V elim V -V
+[ * #i #U #t #H
+ [ lapply (lifts_inv_sort2 … H) -H #H destruct
+ | elim (lifts_inv_lref2 … H) -H
+ #x #_ #H destruct
+ | lapply (lifts_inv_gref2 … H) -H #H destruct
+ ]
+| * [ #a ] #I #V2 #T2 #IHV2 #_ #U #t #H
+ [ elim (lifts_inv_bind2 … H) -H #V1 #T1 #HV12 #_ #H destruct /2 width=3 by/
+ | elim (lifts_inv_flat2 … H) -H #V1 #T1 #HV12 #_ #H destruct /2 width=3 by/
+ ]
+]
+qed-.
+
+(* Basic_1: includes: thead_x_lift_y_y *)
+(* Basic_2A1: includes: lift_inv_pair_xy_y *)
+lemma lifts_inv_pair_xy_y: ∀I,T,V,t. ⬆*[t] ②{I}V.T ≡ T → ⊥.
+#J #T elim T -T
+[ * #i #W #t #H
+ [ lapply (lifts_inv_sort2 … H) -H #H destruct
+ | elim (lifts_inv_lref2 … H) -H
+ #x #_ #H destruct
+ | lapply (lifts_inv_gref2 … H) -H #H destruct
+ ]
+| * [ #a ] #I #V2 #T2 #_ #IHT2 #W #t #H
+ [ elim (lifts_inv_bind2 … H) -H #V1 #T1 #_ #HT12 #H destruct /2 width=4 by/
+ | elim (lifts_inv_flat2 … H) -H #V1 #T1 #_ #HT12 #H destruct /2 width=4 by/
+ ]
+]
+qed-.
+
+(* Basic forward lemmas *****************************************************)
+
+(* Basic_2A1: includes: lift_inv_O2 *)
+lemma lifts_fwd_isid: ∀T1,T2,t. ⬆*[t] T1 ≡ T2 → 𝐈⦃t⦄ → T1 = T2.
+#T1 #T2 #t #H elim H -T1 -T2 -t /4 width=3 by isid_inv_at, eq_f2, eq_f/
+qed-.
+
+(* Basic_2A1: includes: lift_fwd_pair1 *)
+lemma lifts_fwd_pair1: ∀I,V1,T1,Y,t. ⬆*[t] ②{I}V1.T1 ≡ Y →
+ ∃∃V2,T2. ⬆*[t] V1 ≡ V2 & Y = ②{I}V2.T2.
+* [ #a ] #I #V1 #T1 #Y #t #H
+[ elim (lifts_inv_bind1 … H) -H /2 width=4 by ex2_2_intro/
+| elim (lifts_inv_flat1 … H) -H /2 width=4 by ex2_2_intro/
+]
+qed-.
+
+(* Basic_2A1: includes: lift_fwd_pair2 *)
+lemma lifts_fwd_pair2: ∀I,V2,T2,X,t. ⬆*[t] X ≡ ②{I}V2.T2 →
+ ∃∃V1,T1. ⬆*[t] V1 ≡ V2 & X = ②{I}V1.T1.
+* [ #a ] #I #V2 #T2 #X #t #H
+[ elim (lifts_inv_bind2 … H) -H /2 width=4 by ex2_2_intro/
+| elim (lifts_inv_flat2 … H) -H /2 width=4 by ex2_2_intro/
+]
+qed-.
+
+(* Basic properties *********************************************************)
+
+(* Basic_1: includes: lift_free (right to left) *)
+(* Basic_2A1: includes: lift_split *)
+lemma lifts_split_trans: ∀T1,T2,t. ⬆*[t] T1 ≡ T2 →
+ ∀t1,t2. t2 ⊚ t1 ≡ t →
+ ∃∃T. ⬆*[t1] T1 ≡ T & ⬆*[t2] T ≡ T2.
+#T1 #T2 #t #H elim H -T1 -T2 -t
+[ /3 width=3 by lifts_sort, ex2_intro/
+| #i1 #i2 #t #Hi #t1 #t2 #Ht elim (after_at_fwd … Ht … Hi) -Ht -Hi
+ /3 width=3 by lifts_lref, ex2_intro/
+| /3 width=3 by lifts_gref, ex2_intro/
+| #a #I #V1 #V2 #T1 #T2 #t #_ #_ #IHV #IHT #t1 #t2 #Ht
+ elim (IHV … Ht) elim (IHT (Ⓣ@t1) (Ⓣ@t2)) -IHV -IHT
+ /3 width=5 by lifts_bind, after_true, ex2_intro/
+| #I #V1 #V2 #T1 #T2 #t #_ #_ #IHV #IHT #t1 #t2 #Ht
+ elim (IHV … Ht) elim (IHT … Ht) -IHV -IHT -Ht
+ /3 width=5 by lifts_flat, ex2_intro/
+]
+qed-.
+
+(* Note: apparently, this was missing in Basic_2A1 *)
+lemma lifts_split_div: ∀T1,T2,t1. ⬆*[t1] T1 ≡ T2 →
+ ∀t2,t. t2 ⊚ t1 ≡ t →
+ ∃∃T. ⬆*[t2] T2 ≡ T & ⬆*[t] T1 ≡ T.
+#T1 #T2 #t1 #H elim H -T1 -T2 -t1
+[ /3 width=3 by lifts_sort, ex2_intro/
+| #i1 #i2 #t1 #Hi #t2 #t #Ht elim (after_at1_fwd … Ht … Hi) -Ht -Hi
+ /3 width=3 by lifts_lref, ex2_intro/
+| /3 width=3 by lifts_gref, ex2_intro/
+| #a #I #V1 #V2 #T1 #T2 #t1 #_ #_ #IHV #IHT #t2 #t #Ht
+ elim (IHV … Ht) elim (IHT (Ⓣ@t2) (Ⓣ@t)) -IHV -IHT
+ /3 width=5 by lifts_bind, after_true, ex2_intro/
+| #I #V1 #V2 #T1 #T2 #t1 #_ #_ #IHV #IHT #t2 #t #Ht
+ elim (IHV … Ht) elim (IHT … Ht) -IHV -IHT -Ht
+ /3 width=5 by lifts_flat, ex2_intro/
+]
+qed-.
+
+(* Basic_1: includes: dnf_dec2 dnf_dec *)
+(* Basic_2A1: includes: is_lift_dec *)
+lemma is_lifts_dec: ∀T2,t. Decidable (∃T1. ⬆*[t] T1 ≡ T2).
+#T1 elim T1 -T1
+[ * [1,3: /3 width=2 by lifts_sort, lifts_gref, ex_intro, or_introl/ ]
+ #i2 #t elim (is_at_dec t i2)
+ [ * /4 width=3 by lifts_lref, ex_intro, or_introl/
+ | #H @or_intror *
+ #X #HX elim (lifts_inv_lref2 … HX) -HX
+ /3 width=2 by ex_intro/
+ ]
+| * [ #a ] #I #V2 #T2 #IHV2 #IHT2 #t
+ [ elim (IHV2 t) -IHV2
+ [ * #V1 #HV12 elim (IHT2 (Ⓣ@t)) -IHT2
+ [ * #T1 #HT12 @or_introl /3 width=2 by lifts_bind, ex_intro/
+ | -V1 #HT2 @or_intror * #X #H
+ elim (lifts_inv_bind2 … H) -H /3 width=2 by ex_intro/
+ ]
+ | -IHT2 #HV2 @or_intror * #X #H
+ elim (lifts_inv_bind2 … H) -H /3 width=2 by ex_intro/
+ ]
+ | elim (IHV2 t) -IHV2
+ [ * #V1 #HV12 elim (IHT2 t) -IHT2
+ [ * #T1 #HT12 /4 width=2 by lifts_flat, ex_intro, or_introl/
+ | -V1 #HT2 @or_intror * #X #H
+ elim (lifts_inv_flat2 … H) -H /3 width=2 by ex_intro/
+ ]
+ | -IHT2 #HV2 @or_intror * #X #H
+ elim (lifts_inv_flat2 … H) -H /3 width=2 by ex_intro/
+ ]
+ ]
+]
+qed-.
+
+(* Basic_2A1: removed theorems 17:
+ lifts_inv_nil lifts_inv_cons lifts_total
+ lift_inv_Y1 lift_inv_Y2 lift_inv_lref_Y1 lift_inv_lref_Y2 lift_lref_Y lift_Y1
+ lift_lref_lt_eq lift_lref_ge_eq lift_lref_plus lift_lref_pred
+ lift_lref_ge_minus lift_lref_ge_minus_eq lift_total lift_refl
+*)
+(* Basic_1: removed theorems 8:
+ lift_lref_gt
+ lift_head lift_gen_head
+ lift_weight_map lift_weight lift_weight_add lift_weight_add_O
+ lift_tlt_dx
+*)