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/arith/nat.ma".
16 include "static_2/notation/functions/uparrow_1_0.ma".
18 (* SORT HIERARCHY ***********************************************************)
20 (* sort hierarchy specification *)
21 record sh: Type[0] ≝ {
22 sh_next: nat → nat (* next sort in the hierarchy *)
25 interpretation "next sort (sort hierarchy)"
26 'UpArrow_1_0 h = (sh_next h).
28 definition sh_is_next (h): relation nat ≝