1) (⫯f)@(1) = 1
2) f@❨d-n❩ = k → n <= d → (f∘𝐮❨n❩)@❨d❩ = k
3) f@❨d-1❩ = k-1 → 1 < d → 1 < k → (⫯f)@❨d❩ = k
+
+
+lemma pr_pat_after_uni_tls (i2) (i1):
+ ∀f2. @❨i1, f2❩ ≘ i2 →
+ ∀f. 𝐮❨i2❩ ⊚ ⫰*[i2] f2 ≘ f → f2 ⊚ 𝐮❨i1❩ ≘ f.
include "delayed_updating/reduction/dfr.ma".
include "delayed_updating/reduction/ifr.ma".
include "delayed_updating/substitution/fsubst_lift.ma".
+include "delayed_updating/substitution/fsubst_eq.ma".
+include "delayed_updating/substitution/lift_constructors.ma".
include "delayed_updating/substitution/lift_structure_depth.ma".
include "delayed_updating/syntax/prototerm_proper_constructors.ma".
include "delayed_updating/syntax/path_structure_depth.ma".
@(subset_eq_trans … Ht2) -t2
@(subset_eq_trans … (lift_fsubst …))
[ <structure_append <structure_A_sn <structure_append <structure_L_sn
+ @fsubst_eq_repl [ // ]
+ @(subset_eq_trans … (lift_iref …))
| //
| /2 width=2 by ex_intro/
| //
--- /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 "delayed_updating/substitution/fsubst.ma".
+include "delayed_updating/syntax/prototerm_equivalence.ma".
+
+(* Constructions with subset_equivalence ************************************)
+
+lemma subset_inclusion_fsubst_bi (t1) (t2) (u1) (u2) (p):
+ t1 ⊆ t2 → u1 ⊆ u2 → t1[⋔p←u1] ⊆ t2[⋔p←u2].
+#t1 #t2 #u1 #u2 #p #Ht #Hu #q * *
+[ #r #Hr #H0 destruct
+ /4 width=3 by ex2_intro, or_introl/
+| /4 width=2 by or_intror, conj/
+]
+qed.
+
+lemma fsubst_eq_repl (t1) (t2) (u1) (u2) (p):
+ t1 ⇔ t2 → u1 ⇔ u2 → t1[⋔p←u1] ⇔ t2[⋔p←u2].
+#t1 #t2 #u1 #u2 #p * #H1t #H2t * #H1u #H2u
+/3 width=5 by conj, subset_inclusion_fsubst_bi/
+qed.
--- /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/lib/subset_equivalence.ma".
+include "delayed_updating/syntax/preterm.ma".
+include "delayed_updating/substitution/lift_structure.ma".
+include "delayed_updating/substitution/lift_prototerm.ma".
+
+(* LIFT FOR PRETERM *********************************************************)
+
+(* Constructions with subset_equivalence ************************************)
+
+lemma lift_grafted_S_sn (f) (t) (p):
+ ↑[↑[p]f](t⋔(p◖𝗦)) ⊆ (↑[f]t)⋔((⊗p)◖𝗦).
+#f #t #p #q * #r #Hr #H0 destruct
+@(ex2_intro … Hr) -Hr
+<list_append_rcons_sn <list_append_rcons_sn
+<lift_append_proper_dx //
+qed-.
+
+lemma lift_grafted_S_dx (f) (t) (p): p ϵ ▵t → t ϵ 𝐓 →
+ (↑[f]t)⋔((⊗p)◖𝗦) ⊆ ↑[↑[p]f](t⋔(p◖𝗦)).
+#f #t #p #Hp #Ht #q * #r #Hr
+<list_append_rcons_sn #H0
+elim (lift_inv_append_proper_dx … (sym_eq … H0)) -H0 //
+#p0 #q0 #Hp0 #Hq0 #H0 destruct
+<(Ht … Hp0) [|*: /2 width=2 by ex_intro/ ] -p
+elim (lift_path_inv_S_sn … (sym_eq … Hq0)) -Hq0
+#r1 #r2 #Hr1 #Hr2 #H0 destruct
+lapply (preterm_in_root_append_inv_structure_empty_dx … p0 … Ht Hr1)
+[ /2 width=2 by ex_intro/ ] -Hr1 #Hr1 destruct
+/2 width=1 by in_comp_lift_bi/
+qed-.
+
+lemma lift_grafted_S (f) (t) (p): p ϵ ▵t → t ϵ 𝐓 →
+ ↑[↑[p]f](t⋔(p◖𝗦)) ⇔ (↑[f]t)⋔((⊗p)◖𝗦).
+/3 width=1 by lift_grafted_S_sn, conj, lift_grafted_S_dx/ qed.
| @subset_inclusion_ext_f1_compose
| @subset_equivalence_ext_f1_exteq /2 width=5/
]
-qed.
+qed.
interpretation
"preterm (prototerm)"
'ClassT = (structure_injective).
+
+(* Basic inversions *********************************************************)
+
+lemma preterm_in_root_append_inv_structure_empty_dx (t) (p) (r):
+ p●r ϵ ▵t → t ϵ 𝐓 → 𝐞 = ⊗r → 𝐞 = r.
+#t #p #r #Hpr #Ht #Hr
+lapply (Ht p ?? Hpr ?)
+[ <structure_append //
+| /2 width=2 by prototerm_in_root_append_des_sn/
+| /2 width=3 by eq_inv_list_append_dx_sn_refl/
+]
+qed-.
p ϵ t → p ϵ ▵t.
/2 width=2 by ex_intro/
qed.
+
+(* Basic destructions *******************************************************)
+
+lemma prototerm_in_root_append_des_sn (t) (p) (q):
+ p●q ϵ ▵t → p ϵ ▵t.
+#t #p #q * #r #Hr
+/2 width=2 by ex_intro/
+qed-.
]
qed-.
+(* Advanced inversions ******************************************************)
+
+lemma eq_inv_list_append_dx_sn_refl (A) (l1) (l2):
+ l1 = l1⨁{A}l2 → ⓔ = l2.
+#A #l1 elim l1 -l1 [ // ]
+#a1 #l1 #IH #l2 <list_append_lcons_sn #H0 destruct -H0
+/2 width=1 by/
+qed-.
+
(* Advanced eliminations ****************************************************)
lemma list_ind_append_dx (A) (Q:predicate …):