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[helm.git] / helm / matita / contribs / LAMBDA-TYPES / tlt_defs.ma

diff --git a/helm/matita/contribs/LAMBDA-TYPES/tlt_defs.ma b/helm/matita/contribs/LAMBDA-TYPES/tlt_defs.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                  *)
+(*                                                                        *)
+(**************************************************************************)
+
+set "baseuri" "cic:/matita/LAMBDA-TYPES/tlt_defs".
+
+include "terms_defs.ma".
+
+definition wadd: (nat \to nat) \to nat \to (nat \to nat) \def 
+   \lambda map,w,n.
+   match n with [
+        O     \Rightarrow w
+      | (S m) \Rightarrow (map m)
+   ].
+
+let rec weight_map (A:Set) (N:Set) (map:nat \to nat) (t:T A N) on t : nat \def 
+   match t with [
+        (TSort y k)     \Rightarrow O
+      | (TLRef y i)     \Rightarrow (map i)
+      | (TWag y z w u) \Rightarrow
+         match z with [
+              (Bind b) \Rightarrow
+                 match b with [
+                      Abbr \Rightarrow
+                        (S ((weight_map A N map w) + (weight_map A N (wadd map (S (weight_map A N map w))) u)))
+                    | Abst \Rightarrow 
+                        (S ((weight_map A N map w) + (weight_map A N (wadd map O) u)))
+                    | Void \Rightarrow 
+                        (S ((weight_map A N map w) + (weight_map A N (wadd map O) u)))
+                 ]
+            | (Flat a) \Rightarrow
+                 (S ((weight_map A N map w) + (weight_map A N map u)))
+         ]
+      | (TGRef y n)     \Rightarrow O
+  ].
+
+definition weight: \forall A,N. T A N \to nat \def 
+   \lambda A,N. 
+   (weight_map A N (\lambda _.O)).
+
+definition tlt: \forall A,N. T A N \to T A N \to Prop \def 
+   \lambda A,N,t1,t2. 
+   weight A N t1 < weight A N t2.