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diff --git a/matita/matita/contribs/lambdadelta/basic_2/relocation/lifts.ma b/matita/matita/contribs/lambdadelta/basic_2/relocation/lifts.ma
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-
-(**************************************************************************)
-(*       ___                                                              *)
-(*      ||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/nstream_after.ma".
-include "basic_2/notation/relations/rliftstar_3.ma".
-include "basic_2/syntax/term.ma".
-
-(* GENERIC RELOCATION FOR TERMS *********************************************)
-
-(* Basic_1: includes:
-            lift_sort lift_lref_lt lift_lref_ge lift_bind lift_flat
-            lifts_nil lifts_cons
-*)
-inductive lifts: rtmap → relation term ≝
-| lifts_sort: ∀f,s. lifts f (⋆s) (⋆s)
-| lifts_lref: ∀f,i1,i2. @⦃i1, f⦄ ≘ i2 → lifts f (#i1) (#i2)
-| lifts_gref: ∀f,l. lifts f (§l) (§l)
-| lifts_bind: ∀f,p,I,V1,V2,T1,T2.
-              lifts f V1 V2 → lifts (⫯f) T1 T2 →
-              lifts f (ⓑ{p,I}V1.T1) (ⓑ{p,I}V2.T2)
-| lifts_flat: ∀f,I,V1,V2,T1,T2.
-              lifts f V1 V2 → lifts f T1 T2 →
-              lifts f (ⓕ{I}V1.T1) (ⓕ{I}V2.T2)
-.
-
-interpretation "uniform relocation (term)"
-   'RLiftStar i T1 T2 = (lifts (uni i) T1 T2).
-
-interpretation "generic relocation (term)"
-   'RLiftStar f T1 T2 = (lifts f T1 T2).
-
-definition liftable2_sn: predicate (relation term) ≝
-                         λR. ∀T1,T2. R T1 T2 → ∀f,U1. ⬆*[f] T1 ≘ U1 → 
-                         ∃∃U2. ⬆*[f] T2 ≘ U2 & R U1 U2.
-
-definition deliftable2_sn: predicate (relation term) ≝
-                           λR. ∀U1,U2. R U1 U2 → ∀f,T1. ⬆*[f] T1 ≘ U1 →
-                           ∃∃T2. ⬆*[f] T2 ≘ U2 & R T1 T2.
-
-definition liftable2_bi: predicate (relation term) ≝
-                         λR. ∀T1,T2. R T1 T2 → ∀f,U1. ⬆*[f] T1 ≘ U1 → 
-                         ∀U2. ⬆*[f] T2 ≘ U2 → R U1 U2.
-
-definition deliftable2_bi: predicate (relation term) ≝
-                           λR. ∀U1,U2. R U1 U2 → ∀f,T1. ⬆*[f] T1 ≘ U1 →
-                           ∀T2. ⬆*[f] T2 ≘ U2 → R T1 T2.
-
-(* Basic inversion lemmas ***************************************************)
-
-fact lifts_inv_sort1_aux: ∀f,X,Y. ⬆*[f] X ≘ Y → ∀s. X = ⋆s → Y = ⋆s.
-#f #X #Y * -f -X -Y //
-[ #f #i1 #i2 #_ #x #H destruct
-| #f #p #I #V1 #V2 #T1 #T2 #_ #_ #x #H destruct
-| #f #I #V1 #V2 #T1 #T2 #_ #_ #x #H destruct
-]
-qed-.
-
-(* Basic_1: was: lift1_sort *)
-(* Basic_2A1: includes: lift_inv_sort1 *)
-lemma lifts_inv_sort1: ∀f,Y,s. ⬆*[f] ⋆s ≘ Y → Y = ⋆s.
-/2 width=4 by lifts_inv_sort1_aux/ qed-.
-
-fact lifts_inv_lref1_aux: ∀f,X,Y. ⬆*[f] X ≘ Y → ∀i1. X = #i1 →
-                          ∃∃i2. @⦃i1, f⦄ ≘ i2 & Y = #i2.
-#f #X #Y * -f -X -Y
-[ #f #s #x #H destruct
-| #f #i1 #i2 #Hi12 #x #H destruct /2 width=3 by ex2_intro/
-| #f #l #x #H destruct
-| #f #p #I #V1 #V2 #T1 #T2 #_ #_ #x #H destruct
-| #f #I #V1 #V2 #T1 #T2 #_ #_ #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: ∀f,Y,i1. ⬆*[f] #i1 ≘ Y →
-                       ∃∃i2. @⦃i1, f⦄ ≘ i2 & Y = #i2.
-/2 width=3 by lifts_inv_lref1_aux/ qed-.
-
-fact lifts_inv_gref1_aux: ∀f,X,Y. ⬆*[f] X ≘ Y → ∀l. X = §l → Y = §l.
-#f #X #Y * -f -X -Y //
-[ #f #i1 #i2 #_ #x #H destruct
-| #f #p #I #V1 #V2 #T1 #T2 #_ #_ #x #H destruct
-| #f #I #V1 #V2 #T1 #T2 #_ #_ #x #H destruct
-]
-qed-.
-
-(* Basic_2A1: includes: lift_inv_gref1 *)
-lemma lifts_inv_gref1: ∀f,Y,l. ⬆*[f] §l ≘ Y → Y = §l.
-/2 width=4 by lifts_inv_gref1_aux/ qed-.
-
-fact lifts_inv_bind1_aux: ∀f,X,Y. ⬆*[f] X ≘ Y →
-                          ∀p,I,V1,T1. X = ⓑ{p,I}V1.T1 →
-                          ∃∃V2,T2. ⬆*[f] V1 ≘ V2 & ⬆*[⫯f] T1 ≘ T2 &
-                                   Y = ⓑ{p,I}V2.T2.
-#f #X #Y * -f -X -Y
-[ #f #s #q #J #W1 #U1 #H destruct
-| #f #i1 #i2 #_ #q #J #W1 #U1 #H destruct
-| #f #l #b #J #W1 #U1 #H destruct
-| #f #p #I #V1 #V2 #T1 #T2 #HV12 #HT12 #q #J #W1 #U1 #H destruct /2 width=5 by ex3_2_intro/
-| #f #I #V1 #V2 #T1 #T2 #_ #_ #q #J #W1 #U1 #H destruct
-]
-qed-.
-
-(* Basic_1: was: lift1_bind *)
-(* Basic_2A1: includes: lift_inv_bind1 *)
-lemma lifts_inv_bind1: ∀f,p,I,V1,T1,Y. ⬆*[f] ⓑ{p,I}V1.T1 ≘ Y →
-                       ∃∃V2,T2. ⬆*[f] V1 ≘ V2 & ⬆*[⫯f] T1 ≘ T2 &
-                                Y = ⓑ{p,I}V2.T2.
-/2 width=3 by lifts_inv_bind1_aux/ qed-.
-
-fact lifts_inv_flat1_aux: ∀f:rtmap. ∀X,Y. ⬆*[f] X ≘ Y →
-                          ∀I,V1,T1. X = ⓕ{I}V1.T1 →
-                          ∃∃V2,T2. ⬆*[f] V1 ≘ V2 & ⬆*[f] T1 ≘ T2 &
-                                   Y = ⓕ{I}V2.T2.
-#f #X #Y * -f -X -Y
-[ #f #s #J #W1 #U1 #H destruct
-| #f #i1 #i2 #_ #J #W1 #U1 #H destruct
-| #f #l #J #W1 #U1 #H destruct
-| #f #p #I #V1 #V2 #T1 #T2 #_ #_ #J #W1 #U1 #H destruct
-| #f #I #V1 #V2 #T1 #T2 #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: ∀f:rtmap. ∀I,V1,T1,Y. ⬆*[f] ⓕ{I}V1.T1 ≘ Y →
-                       ∃∃V2,T2. ⬆*[f] V1 ≘ V2 & ⬆*[f] T1 ≘ T2 &
-                                Y = ⓕ{I}V2.T2.
-/2 width=3 by lifts_inv_flat1_aux/ qed-.
-
-fact lifts_inv_sort2_aux: ∀f,X,Y. ⬆*[f] X ≘ Y → ∀s. Y = ⋆s → X = ⋆s.
-#f #X #Y * -f -X -Y //
-[ #f #i1 #i2 #_ #x #H destruct
-| #f #p #I #V1 #V2 #T1 #T2 #_ #_ #x #H destruct
-| #f #I #V1 #V2 #T1 #T2 #_ #_ #x #H destruct
-]
-qed-.
-
-(* Basic_1: includes: lift_gen_sort *)
-(* Basic_2A1: includes: lift_inv_sort2 *)
-lemma lifts_inv_sort2: ∀f,X,s. ⬆*[f] X ≘ ⋆s → X = ⋆s.
-/2 width=4 by lifts_inv_sort2_aux/ qed-.
-
-fact lifts_inv_lref2_aux: ∀f,X,Y. ⬆*[f] X ≘ Y → ∀i2. Y = #i2 →
-                          ∃∃i1. @⦃i1, f⦄ ≘ i2 & X = #i1.
-#f #X #Y * -f -X -Y
-[ #f #s #x #H destruct
-| #f #i1 #i2 #Hi12 #x #H destruct /2 width=3 by ex2_intro/
-| #f #l #x #H destruct
-| #f #p #I #V1 #V2 #T1 #T2 #_ #_ #x #H destruct
-| #f #I #V1 #V2 #T1 #T2 #_ #_ #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: ∀f,X,i2. ⬆*[f] X ≘ #i2 →
-                       ∃∃i1. @⦃i1, f⦄ ≘ i2 & X = #i1.
-/2 width=3 by lifts_inv_lref2_aux/ qed-.
-
-fact lifts_inv_gref2_aux: ∀f,X,Y. ⬆*[f] X ≘ Y → ∀l. Y = §l → X = §l.
-#f #X #Y * -f -X -Y //
-[ #f #i1 #i2 #_ #x #H destruct
-| #f #p #I #V1 #V2 #T1 #T2 #_ #_ #x #H destruct
-| #f #I #V1 #V2 #T1 #T2 #_ #_ #x #H destruct
-]
-qed-.
-
-(* Basic_2A1: includes: lift_inv_gref1 *)
-lemma lifts_inv_gref2: ∀f,X,l. ⬆*[f] X ≘ §l → X = §l.
-/2 width=4 by lifts_inv_gref2_aux/ qed-.
-
-fact lifts_inv_bind2_aux: ∀f,X,Y. ⬆*[f] X ≘ Y →
-                          ∀p,I,V2,T2. Y = ⓑ{p,I}V2.T2 →
-                          ∃∃V1,T1. ⬆*[f] V1 ≘ V2 & ⬆*[⫯f] T1 ≘ T2 &
-                                   X = ⓑ{p,I}V1.T1.
-#f #X #Y * -f -X -Y
-[ #f #s #q #J #W2 #U2 #H destruct
-| #f #i1 #i2 #_ #q #J #W2 #U2 #H destruct
-| #f #l #q #J #W2 #U2 #H destruct
-| #f #p #I #V1 #V2 #T1 #T2 #HV12 #HT12 #q #J #W2 #U2 #H destruct /2 width=5 by ex3_2_intro/
-| #f #I #V1 #V2 #T1 #T2 #_ #_ #q #J #W2 #U2 #H destruct
-]
-qed-.
-
-(* Basic_1: includes: lift_gen_bind *)
-(* Basic_2A1: includes: lift_inv_bind2 *)
-lemma lifts_inv_bind2: ∀f,p,I,V2,T2,X. ⬆*[f] X ≘ ⓑ{p,I}V2.T2 →
-                       ∃∃V1,T1. ⬆*[f] V1 ≘ V2 & ⬆*[⫯f] T1 ≘ T2 &
-                                X = ⓑ{p,I}V1.T1.
-/2 width=3 by lifts_inv_bind2_aux/ qed-.
-
-fact lifts_inv_flat2_aux: ∀f:rtmap. ∀X,Y. ⬆*[f] X ≘ Y →
-                          ∀I,V2,T2. Y = ⓕ{I}V2.T2 →
-                          ∃∃V1,T1. ⬆*[f] V1 ≘ V2 & ⬆*[f] T1 ≘ T2 &
-                                   X = ⓕ{I}V1.T1.
-#f #X #Y * -f -X -Y
-[ #f #s #J #W2 #U2 #H destruct
-| #f #i1 #i2 #_ #J #W2 #U2 #H destruct
-| #f #l #J #W2 #U2 #H destruct
-| #f #p #I #V1 #V2 #T1 #T2 #_ #_ #J #W2 #U2 #H destruct
-| #f #I #V1 #V2 #T1 #T2 #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: ∀f:rtmap. ∀I,V2,T2,X. ⬆*[f] X ≘ ⓕ{I}V2.T2 →
-                       ∃∃V1,T1. ⬆*[f] V1 ≘ V2 & ⬆*[f] T1 ≘ T2 &
-                                X = ⓕ{I}V1.T1.
-/2 width=3 by lifts_inv_flat2_aux/ qed-.
-
-(* Advanced inversion lemmas ************************************************)
-
-lemma lifts_inv_atom1: ∀f,I,Y. ⬆*[f] ⓪{I} ≘ Y →
-                       ∨∨ ∃∃s. I = Sort s & Y = ⋆s
-                        | ∃∃i,j. @⦃i, f⦄ ≘ j & I = LRef i & Y = #j
-                        | ∃∃l. I = GRef l & Y = §l.
-#f * #n #Y #H
-[ lapply (lifts_inv_sort1 … H)
-| elim (lifts_inv_lref1 … H)
-| lapply (lifts_inv_gref1 … H)
-] -H /3 width=5 by or3_intro0, or3_intro1, or3_intro2, ex3_2_intro, ex2_intro/
-qed-.
-
-lemma lifts_inv_atom2: ∀f,I,X. ⬆*[f] X ≘ ⓪{I} →
-                       ∨∨ ∃∃s. X = ⋆s & I = Sort s
-                        | ∃∃i,j. @⦃i, f⦄ ≘ j & X = #i & I = LRef j
-                        | ∃∃l. X = §l & I = GRef l.
-#f * #n #X #H
-[ lapply (lifts_inv_sort2 … H)
-| elim (lifts_inv_lref2 … H)
-| lapply (lifts_inv_gref2 … H)
-] -H /3 width=5 by or3_intro0, or3_intro1, or3_intro2, ex3_2_intro, ex2_intro/
-qed-.
-
-(* Basic_2A1: includes: lift_inv_pair_xy_x *)
-lemma lifts_inv_pair_xy_x: ∀f,I,V,T. ⬆*[f] ②{I}V.T ≘ V → ⊥.
-#f #J #V elim V -V
-[ * #i #U #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
-  ]
-| * [ #p ] #I #V2 #T2 #IHV2 #_ #U #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,f. ⬆*[f] ②{I}V.T ≘ T → ⊥.
-#J #T elim T -T
-[ * #i #W #f #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
-  ]
-| * [ #p ] #I #V2 #T2 #_ #IHT2 #W #f #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-.
-
-(* Inversion lemmas with uniform relocations ********************************)
-
-lemma lifts_inv_lref1_uni: ∀l,Y,i. ⬆*[l] #i ≘ Y → Y = #(l+i).
-#l #Y #i1 #H elim (lifts_inv_lref1 … H) -H /4 width=4 by at_mono, eq_f/
-qed-.
-
-lemma lifts_inv_lref2_uni: ∀l,X,i2. ⬆*[l] X ≘ #i2 →
-                           ∃∃i1. X = #i1 & i2 = l + i1.
-#l #X #i2 #H elim (lifts_inv_lref2 … H) -H
-/3 width=3 by at_inv_uni, ex2_intro/
-qed-.
-
-lemma lifts_inv_lref2_uni_ge: ∀l,X,i. ⬆*[l] X ≘ #(l + i) → X = #i.
-#l #X #i2 #H elim (lifts_inv_lref2_uni … H) -H
-#i1 #H1 #H2 destruct /4 width=2 by injective_plus_r, eq_f, sym_eq/
-qed-.
-
-lemma lifts_inv_lref2_uni_lt: ∀l,X,i. ⬆*[l] X ≘ #i → i < l → ⊥.
-#l #X #i2 #H elim (lifts_inv_lref2_uni … H) -H
-#i1 #_ #H1 #H2 destruct /2 width=4 by lt_le_false/
-qed-.
-
-(* Basic forward lemmas *****************************************************)
-
-(* Basic_2A1: includes: lift_inv_O2 *)
-lemma lifts_fwd_isid: ∀f,T1,T2. ⬆*[f] T1 ≘ T2 → 𝐈⦃f⦄ → T1 = T2.
-#f #T1 #T2 #H elim H -f -T1 -T2
-/4 width=3 by isid_inv_at_mono, isid_push, eq_f2, eq_f/
-qed-.
-
-(* Basic_2A1: includes: lift_fwd_pair1 *)
-lemma lifts_fwd_pair1: ∀f:rtmap. ∀I,V1,T1,Y. ⬆*[f] ②{I}V1.T1 ≘ Y →
-                       ∃∃V2,T2. ⬆*[f] V1 ≘ V2 & Y = ②{I}V2.T2.
-#f * [ #p ] #I #V1 #T1 #Y #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: ∀f:rtmap. ∀I,V2,T2,X. ⬆*[f] X ≘ ②{I}V2.T2 →
-                       ∃∃V1,T1. ⬆*[f] V1 ≘ V2 & X = ②{I}V1.T1.
-#f * [ #p ] #I #V2 #T2 #X #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 *********************************************************)
-
-lemma lifts_eq_repl_back: ∀T1,T2. eq_repl_back … (λf. ⬆*[f] T1 ≘ T2).
-#T1 #T2 #f1 #H elim H -T1 -T2 -f1
-/4 width=5 by lifts_flat, lifts_bind, lifts_lref, at_eq_repl_back, eq_push/
-qed-.
-
-lemma lifts_eq_repl_fwd: ∀T1,T2. eq_repl_fwd … (λf. ⬆*[f] T1 ≘ T2).
-#T1 #T2 @eq_repl_sym /2 width=3 by lifts_eq_repl_back/ (**) (* full auto fails *)
-qed-.
-
-(* Basic_1: includes: lift_r *)
-(* Basic_2A1: includes: lift_refl *)
-lemma lifts_refl: ∀T,f. 𝐈⦃f⦄ → ⬆*[f] T ≘ T.
-#T elim T -T *
-/4 width=3 by lifts_flat, lifts_bind, lifts_lref, isid_inv_at, isid_push/
-qed.
-
-(* Basic_2A1: includes: lift_total *)
-lemma lifts_total: ∀T1,f. ∃T2. ⬆*[f] T1 ≘ T2.
-#T1 elim T1 -T1 *
-/3 width=2 by lifts_lref, lifts_sort, lifts_gref, ex_intro/
-[ #p ] #I #V1 #T1 #IHV1 #IHT1 #f
-elim (IHV1 f) -IHV1 #V2 #HV12
-[ elim (IHT1 (⫯f)) -IHT1 /3 width=2 by lifts_bind, ex_intro/
-| elim (IHT1 f) -IHT1 /3 width=2 by lifts_flat, ex_intro/
-]
-qed-.
-
-lemma lift_lref_uni: ∀l,i. ⬆*[l] #i ≘ #(l+i).
-#l elim l -l /2 width=1 by lifts_lref/
-qed.
-
-(* Basic_1: includes: lift_free (right to left) *)
-(* Basic_2A1: includes: lift_split *)
-lemma lifts_split_trans: ∀f,T1,T2. ⬆*[f] T1 ≘ T2 →
-                         ∀f1,f2. f2 ⊚ f1 ≘ f →
-                         ∃∃T. ⬆*[f1] T1 ≘ T & ⬆*[f2] T ≘ T2.
-#f #T1 #T2 #H elim H -f -T1 -T2
-[ /3 width=3 by lifts_sort, ex2_intro/
-| #f #i1 #i2 #Hi #f1 #f2 #Ht elim (after_at_fwd … Hi … Ht) -Hi -Ht
-  /3 width=3 by lifts_lref, ex2_intro/
-| /3 width=3 by lifts_gref, ex2_intro/
-| #f #p #I #V1 #V2 #T1 #T2 #_ #_ #IHV #IHT #f1 #f2 #Ht
-  elim (IHV … Ht) elim (IHT (⫯f1) (⫯f2)) -IHV -IHT
-  /3 width=5 by lifts_bind, after_O2, ex2_intro/
-| #f #I #V1 #V2 #T1 #T2 #_ #_ #IHV #IHT #f1 #f2 #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: ∀f1,T1,T2. ⬆*[f1] T1 ≘ T2 →
-                       ∀f2,f. f2 ⊚ f1 ≘ f →
-                       ∃∃T. ⬆*[f2] T2 ≘ T & ⬆*[f] T1 ≘ T.
-#f1 #T1 #T2 #H elim H -f1 -T1 -T2
-[ /3 width=3 by lifts_sort, ex2_intro/
-| #f1 #i1 #i2 #Hi #f2 #f #Ht elim (after_at1_fwd … Hi … Ht) -Hi -Ht
-  /3 width=3 by lifts_lref, ex2_intro/
-| /3 width=3 by lifts_gref, ex2_intro/
-| #f1 #p #I #V1 #V2 #T1 #T2 #_ #_ #IHV #IHT #f2 #f #Ht
-  elim (IHV … Ht) elim (IHT (⫯f2) (⫯f)) -IHV -IHT
-  /3 width=5 by lifts_bind, after_O2, ex2_intro/
-| #f1 #I #V1 #V2 #T1 #T2 #_ #_ #IHV #IHT #f2 #f #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,f. Decidable (∃T1. ⬆*[f] T1 ≘ T2).
-#T1 elim T1 -T1
-[ * [1,3: /3 width=2 by lifts_sort, lifts_gref, ex_intro, or_introl/ ]
-  #i2 #f elim (is_at_dec f 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/
-  ]
-| * [ #p ] #I #V2 #T2 #IHV2 #IHT2 #f
-  [ elim (IHV2 f) -IHV2
-    [ * #V1 #HV12 elim (IHT2 (⫯f)) -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 f) -IHV2
-    [ * #V1 #HV12 elim (IHT2 f) -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-.
-
-(* Properties with uniform relocation ***************************************)
-
-lemma lifts_uni: ∀n1,n2,T,U. ⬆*[𝐔❴n1❵∘𝐔❴n2❵] T ≘ U → ⬆*[n1+n2] T ≘ U.
-/3 width=4 by lifts_eq_repl_back, after_inv_total/ qed.
-
-(* Basic_2A1: removed theorems 14:
-              lifts_inv_nil lifts_inv_cons
-              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
-*)
-(* 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
-*)