1 (**************************************************************************)
4 (* ||A|| A project by Andrea Asperti *)
6 (* ||I|| Developers: *)
7 (* ||T|| The HELM team. *)
8 (* ||A|| http://helm.cs.unibo.it *)
10 (* \ / This file is distributed under the terms of the *)
11 (* v GNU General Public License Version 2 *)
13 (**************************************************************************)
15 include "ground/lib/list_rcons.ma".
16 include "ground/notation/functions/element_e_0.ma".
17 include "ground/notation/functions/black_circle_2.ma".
18 include "ground/notation/functions/black_halfcircleright_2.ma".
19 include "ground/notation/functions/black_halfcircleleft_2.ma".
20 include "delayed_updating/syntax/label.ma".
22 (* PATH *********************************************************************)
24 (* Note: a path is a list of labels *)
25 (* Note: constructed from the leaf (right end) to the root (left end) *)
26 definition path ≝ list label.
30 'ElementE = (list_empty label).
34 'BlackHalfCircleLeft p l = (list_lcons label l p).
38 'BlackCircle p q = (list_append label q p).
42 'BlackHalfCircleRight l p = (list_append label p (list_lcons label l (list_empty label))).