+++ /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/unwind/unwind2_rmap.ma".
-include "delayed_updating/syntax/path_structure.ma".
-include "delayed_updating/notation/functions/black_downtriangle_2.ma".
-
-(* TAILED UNWIND FOR PATH ***************************************************)
-
-definition unwind2_path (f) (p): path ≝
-match p with
-[ list_empty ⇒ (𝐞)
-| list_lcons l q ⇒
- match l with
- [ label_d k ⇒ (⊗q)◖𝗱(▶[f]q@⧣❨k❩)
- | label_m ⇒ ⊗p
- | label_L ⇒ ⊗p
- | label_A ⇒ ⊗p
- | label_S ⇒ ⊗p
- ]
-].
-
-interpretation
- "tailed unwind (path)"
- 'BlackDownTriangle f p = (unwind2_path f p).
-
-(* Basic constructions ******************************************************)
-
-lemma unwind2_path_empty (f):
- (𝐞) = ▼[f]𝐞.
-// qed.
-
-lemma unwind2_path_d_dx (f) (p) (k) :
- (⊗p)◖𝗱((▶[f]p)@⧣❨k❩) = ▼[f](p◖𝗱k).
-// qed.
-
-lemma unwind2_path_m_dx (f) (p):
- ⊗p = ▼[f](p◖𝗺).
-// qed.
-
-lemma unwind2_path_L_dx (f) (p):
- (⊗p)◖𝗟 = ▼[f](p◖𝗟).
-// qed.
-
-lemma unwind2_path_A_dx (f) (p):
- (⊗p)◖𝗔 = ▼[f](p◖𝗔).
-// qed.
-
-lemma unwind2_path_S_dx (f) (p):
- (⊗p)◖𝗦 = ▼[f](p◖𝗦).
-// qed.
-
-(* Constructions with structure *********************************************)
-
-lemma structure_unwind2_path (f) (p):
- ⊗p = ⊗▼[f]p.
-#f * // * [ #k ] #p //
-qed.
-
-lemma unwind2_path_structure (f) (p):
- ⊗p = ▼[f]⊗p.
-#f #p elim p -p // * [ #k ] #p #IH //
-[ <structure_L_dx <unwind2_path_L_dx //
-| <structure_A_dx <unwind2_path_A_dx //
-| <structure_S_dx <unwind2_path_S_dx //
-]
-qed.
-
-lemma unwind2_path_root (f) (p):
- ∃∃r. 𝐞 = ⊗r & ⊗p●r = ▼[f]p.
-#f * [| * [ #k ] #p ]
-/2 width=3 by ex2_intro/
-<unwind2_path_d_dx <structure_d_dx
-/2 width=3 by ex2_intro/
-qed-.
-
-(* Destructions with structure **********************************************)
-
-lemma unwind2_path_des_structure (f) (q) (p):
- ⊗q = ▼[f]p → ⊗q = ⊗p.
-// qed-.
-
-(* Basic inversions *********************************************************)
-
-lemma eq_inv_d_dx_unwind2_path (f) (q) (p) (h):
- q◖𝗱h = ▼[f]p →
- ∃∃r,k. q = ⊗r & h = ▶[f]r@⧣❨k❩ & r◖𝗱k = p.
-#f #q * [| * [ #k ] #p ] #h
-[ <unwind2_path_empty #H0 destruct
-| <unwind2_path_d_dx #H0 destruct
- /2 width=5 by ex3_2_intro/
-| <unwind2_path_m_dx #H0
- elim (eq_inv_d_dx_structure … H0)
-| <unwind2_path_L_dx #H0 destruct
-| <unwind2_path_A_dx #H0 destruct
-| <unwind2_path_S_dx #H0 destruct
-]
-qed-.
-
-lemma eq_inv_m_dx_unwind2_path (f) (q) (p):
- q◖𝗺 = ▼[f]p → ⊥.
-#f #q * [| * [ #k ] #p ]
-[ <unwind2_path_empty #H0 destruct
-| <unwind2_path_d_dx #H0 destruct
-| <unwind2_path_m_dx #H0
- elim (eq_inv_m_dx_structure … H0)
-| <unwind2_path_L_dx #H0 destruct
-| <unwind2_path_A_dx #H0 destruct
-| <unwind2_path_S_dx #H0 destruct
-]
-qed-.
-
-lemma eq_inv_L_dx_unwind2_path (f) (q) (p):
- q◖𝗟 = ▼[f]p →
- ∃∃r1,r2. q = ⊗r1 & ∀g. 𝐞 = ▼[g]r2 & r1●𝗟◗r2 = p.
-#f #q * [| * [ #k ] #p ]
-[ <unwind2_path_empty #H0 destruct
-| <unwind2_path_d_dx #H0 destruct
-| <unwind2_path_m_dx #H0
- elim (eq_inv_L_dx_structure … H0) -H0 #r1 #r2 #H1 #H2 #H3 destruct
- /2 width=5 by ex3_2_intro/
-| <unwind2_path_L_dx #H0 destruct
- /2 width=5 by ex3_2_intro/
-| <unwind2_path_A_dx #H0 destruct
-| <unwind2_path_S_dx #H0 destruct
-]
-qed-.
-
-lemma eq_inv_A_dx_unwind2_path (f) (q) (p):
- q◖𝗔 = ▼[f]p →
- ∃∃r1,r2. q = ⊗r1 & ∀g. 𝐞 = ▼[g]r2 & r1●𝗔◗r2 = p.
-#f #q * [| * [ #k ] #p ]
-[ <unwind2_path_empty #H0 destruct
-| <unwind2_path_d_dx #H0 destruct
-| <unwind2_path_m_dx #H0
- elim (eq_inv_A_dx_structure … H0) -H0 #r1 #r2 #H1 #H2 #H3 destruct
- /2 width=5 by ex3_2_intro/
-| <unwind2_path_L_dx #H0 destruct
-| <unwind2_path_A_dx #H0 destruct
- /2 width=5 by ex3_2_intro/
-| <unwind2_path_S_dx #H0 destruct
-]
-qed-.
-
-lemma eq_inv_S_dx_unwind2_path (f) (q) (p):
- q◖𝗦 = ▼[f]p →
- ∃∃r1,r2. q = ⊗r1 & ∀g. 𝐞 = ▼[g]r2 & r1●𝗦◗r2 = p.
-#f #q * [| * [ #k ] #p ]
-[ <unwind2_path_empty #H0 destruct
-| <unwind2_path_d_dx #H0 destruct
-| <unwind2_path_m_dx #H0
- elim (eq_inv_S_dx_structure … H0) -H0 #r1 #r2 #H1 #H2 #H3 destruct
- /2 width=5 by ex3_2_intro/
-| <unwind2_path_L_dx #H0 destruct
-| <unwind2_path_A_dx #H0 destruct
-| <unwind2_path_S_dx #H0 destruct
- /2 width=5 by ex3_2_intro/
-]
-qed-.