- basic_2: reaxiomatized snv with improved cpds and cpes simplifies preservation

[helm.git] / matita / matita / contribs / lambdadelta / alpha_1 / grammar / item.ma

diff --git a/matita/matita/contribs/lambdadelta/alpha_1/grammar/item.ma b/matita/matita/contribs/lambdadelta/alpha_1/grammar/item.ma
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+(**************************************************************************)
+(*       ___                                                              *)
+(*      ||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                  *)
+(*                                                                        *)
+(**************************************************************************)
+
+(* THE FORMAL SYSTEM α: MATITA SOURCE FILES
+ * Initial invocation : - Patience on me to gain peace and perfection! -
+ * Developed since    : 2014 July 25
+ *)
+
+include "ground_2/lib/bool.ma".
+include "ground_2/lib/arith.ma".
+
+(* ITEMS ********************************************************************)
+
+(* unary items *)
+inductive item1: Type[0] ≝
+   | Char: nat → item1 (* character: starting at 0 *)
+   | LRef: nat → item1 (* reference by index: starting at 0 *)
+   | GRef: nat → item1 (* reference by position: starting at 0 *)
+   | Decl:       item1 (* global abstraction *)
+.
+
+(* binary items *)
+inductive item2: Type[0] ≝
+   | Abst:        item2 (* local abstraction *)
+   | Abbr: bool → item2 (* local (Ⓣ) or global (Ⓕ) abbreviation *)
+   | Proj: bool → item2 (* local (Ⓣ) or global (Ⓕ) projection *)
+.