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1 (**************************************************************************)
2 (*       ___                                                              *)
3 (*      ||M||                                                             *)
4 (*      ||A||       A project by Andrea Asperti                           *)
5 (*      ||T||                                                             *)
6 (*      ||I||       Developers:                                           *)
7 (*      ||T||         The HELM team.                                      *)
8 (*      ||A||         http://helm.cs.unibo.it                             *)
9 (*      \   /                                                             *)
10 (*       \ /        This file is distributed under the terms of the       *)
11 (*        v         GNU General Public License Version 2                  *)
12 (*                                                                        *)
13 (**************************************************************************)
14
15 (* THE FORMAL SYSTEM α: MATITA SOURCE FILES
16  * Initial invocation : - Patience on me to gain peace and perfection! -
17  * Developed since    : 2014 July 25
18  *)
19
20 include "ground_2/lib/bool.ma".
21 include "ground_2/lib/arith.ma".
22
23 (* ITEMS ********************************************************************)
24
25 (* unary items *)
26 inductive item1: Type[0] ≝
27    | Char: nat → item1 (* character: starting at 0 *)
28    | LRef: nat → item1 (* reference by index: starting at 0 *)
29    | GRef: nat → item1 (* reference by position: starting at 0 *)
30    | Decl:       item1 (* global abstraction *)
31 .
32
33 (* binary items *)
34 inductive item2: Type[0] ≝
35    | Abst:        item2 (* local abstraction *)
36    | Abbr: bool → item2 (* local (Ⓣ) or global (Ⓕ) abbreviation *)
37    | Proj: bool → item2 (* local (Ⓣ) or global (Ⓕ) projection *)
38 .