+++ /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/syntax/path.ma".
-include "delayed_updating/notation/functions/nec_r_1.ma".
-
-(* REVERSE FOR PATH *********************************************************)
-
-rec definition reverse (p) on p: path ≝
-match p with
-[ list_empty ⇒ 𝐞
-| list_lcons l q ⇒ (reverse q)◖l
-].
-
-interpretation
- "reverse (path)"
- 'NEcR p = (reverse p).
-
-(* Basic constructions ******************************************************)
-
-lemma reverse_empty: 𝐞 = 𝐞ᴿ.
-// qed.
-
-lemma reverse_lcons (p) (l): pᴿ◖l = (l◗p)ᴿ.
-// qed.
-
-(* Main constructions *******************************************************)
-
-theorem reverse_append (p1) (p2):
- (p2ᴿ)●(p1ᴿ) = (p1●p2)ᴿ.
-#p1 elim p1 -p1 //
-#l1 #p1 #IH #p2
-<list_append_lcons_sn <reverse_lcons <reverse_lcons //
-qed.
-
-(* Constructions with list_rcons ********************************************)
-
-lemma reverse_rcons (p) (l):
- l◗(pᴿ) = (p◖l)ᴿ.
-#p #l
-<reverse_append //
-qed.
-
-(* Main constructions *******************************************************)
-
-theorem reverse_reverse (p):
- p = pᴿᴿ.
-#p elim p -p //
-#l #p #IH
-<reverse_lcons <reverse_rcons //
-qed.