include "delayed_updating/substitution/fsubst.ma".
include "delayed_updating/substitution/lift_prototerm_eq.ma".
-(*
-include "delayed_updating/syntax/preterm.ma".
-include "delayed_updating/syntax/prototerm_proper.ma".
-*)
+
(* FOCALIZED SUBSTITUTION ***************************************************)
(* Constructions with lift for preterm **************************************)
lemma lift_term_fsubst_sn (f) (t) (u) (p):
- (↑[f]t)[⋔(↑[f]p)←↑[↑[p]f]u] ⊆ ↑[f](t[⋔p←u]).
+ (🠡[f]t)[⋔(🠡[f]p)←🠡[🠢[f]p]u] ⊆ 🠡[f](t[⋔p←u]).
#f #t #u #p #ql * *
[ #rl * #r #Hr #H1 #H2 destruct
>lift_path_append
qed-.
lemma lift_term_fsubst_dx (f) (t) (u) (p):
- ↑[f](t[⋔p←u]) ⊆ (↑[f]t)[⋔(↑[f]p)←↑[↑[p]f]u].
+ 🠡[f](t[⋔p←u]) ⊆ (🠡[f]t)[⋔(🠡[f]p)←🠡[🠢[f]p]u].
#f #t #u #p #ql * #q * *
[ #r #Hu #H1 #H2 destruct
@or_introl @ex2_intro
/2 width=3 by ex2_intro/
| #Hq #H0 #H1 destruct
@or_intror @conj [ /2 width=1 by in_comp_lift_path_term/ ] -Hq #r #Hr
- elim (lift_path_inv_append_dx … Hr) -Hr #s1 #s2 #Hs1 #_ #H1 destruct
+ elim (lift_path_inv_append_sn … Hr) -Hr #s1 #s2 #Hs1 #_ #H1 destruct
lapply (lift_path_inj … Hs1) -Hs1 #H1 destruct
/2 width=2 by/
]
qed-.
lemma lift_term_fsubst (f) (t) (u) (p):
- (↑[f]t)[⋔(↑[f]p)←↑[↑[p]f]u] ⇔ ↑[f](t[⋔p←u]).
+ (🠡[f]t)[⋔(🠡[f]p)←🠡[🠢[f]p]u] ⇔ 🠡[f](t[⋔p←u]).
/3 width=1 by lift_term_fsubst_sn, conj, lift_term_fsubst_dx/ qed.