include "delayed_updating/notation/functions/m_hook_1.ma".
include "delayed_updating/notation/functions/hash_1.ma".
include "delayed_updating/notation/functions/tau_2.ma".
+include "delayed_updating/notation/functions/tau_3.ma".
include "delayed_updating/notation/functions/lamda_1.ma".
include "delayed_updating/notation/functions/at_2.ma".
"inner variable reference by depth (prototerm)"
'Tau k t = (prototerm_node_1_2 (label_d k) label_m t).
+interpretation
+ "inner variable reference by depth with offset (prototerm)"
+ 'Tau k d t = (prototerm_node_1_2 (label_d2 k d) label_m t).
+
interpretation
"name-free functional abstraction (prototerm)"
'Lamda t = (prototerm_node_1 label_L t).
q ϵ t → 𝗱k◗𝗺◗q ϵ 𝛕k.t.
/2 width=3 by ex2_intro/ qed.
+lemma in_comp_iref2 (t) (q) (k) (d):
+ q ϵ t → 𝗱❨k,d❩◗𝗺◗q ϵ 𝛕❨k,d❩.t.
+/2 width=3 by ex2_intro/ qed.
+
(* Basic inversions *********************************************************)
lemma in_comp_inv_iref (t) (p) (k):
/2 width=3 by ex2_intro/
qed-.
+lemma in_comp_inv_iref2 (t) (p) (k) (d):
+ p ϵ 𝛕❨k,d❩.t →
+ ∃∃q. 𝗱❨k,d❩◗𝗺◗q = p & q ϵ t.
+#t #p #k #d * #q #Hq #Hp
+/2 width=3 by ex2_intro/
+qed-.
+
(* COMMENT
lemma prototerm_in_root_inv_lcons_oref:
∀p,l,n. l◗p ϵ ▵#n →