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update in ground and delayed_updating
[helm.git] / matita / matita / contribs / lambdadelta / delayed_updating / syntax / path_head_structure.ma
index c97fbfb2ef1b7accfc843fd1d177f9f6b6b49c52..e1605752c28ca72d13532e6b2ac93a3f40cb9500 100644 (file)
 (*                                                                        *)
 (**************************************************************************)
 
-include "delayed_updating/syntax/path_head.ma".
-include "delayed_updating/syntax/path_structure.ma".
-include "delayed_updating/syntax/path_depth.ma".
+include "delayed_updating/syntax/path_head_depth.ma".
+include "delayed_updating/syntax/path_structure_labels.ma".
 
 (* HEAD FOR PATH ************************************************************)
 
 (* Constructions with structure *********************************************)
 
-axiom path_head_structure (p) (q):
-      ⊗p = ↳[♭⊗p]((⊗p)●q).
-(*
-#p elim p -p
-[ #q <path_head_zero //
-| * [ #n ] #p #IH #q
-  [ <structure_d_sn //
-  | <structure_m_sn //
-  | <structure_L_sn
-  | <structure_A_sn <list_append_lcons_sn 
-    <path_head_A_sn //
-  | <structure_S_sn //
-  ]
+lemma path_head_structure_height (p) (m):
+      ⊗↳[m]p = ↳[m+♯↳[m]p]⊗p.
+#p elim p -p //
+#l #p #IH #m @(nat_ind_succ … m) -m //
+#m #_ cases l [ #n ]
+[ <height_d_sn <structure_d_sn //
+| <structure_m_sn //
+| <structure_L_sn //
+| <height_A_sn <structure_A_sn <nplus_succ_sn <path_head_A_sn //
+| <height_S_sn <structure_S_sn <nplus_succ_sn <path_head_S_sn //
 ]
-*)
\ No newline at end of file
+qed.
+
+lemma path_head_structure_depth (p) (m):
+      ⊗↳[m]p = ↳[♭↳[m]p]⊗p.
+#p #m
+<path_head_depth //
+qed.