sum_below moved here from Arith

--- a/src/HOL/UNITY/AllocBase.thy	Thu May 25 15:14:39 2000 +0200
+++ b/src/HOL/UNITY/AllocBase.thy	Thu May 25 15:15:22 2000 +0200
@@ -21,4 +21,10 @@
   "tokens [] = 0"
   "tokens (x#xs) = x + tokens xs"
 
+(*Or could be setsum...(lessThan n)*)
+consts sum_below :: "[nat=>'a, nat] => ('a::plus_ac0)"
+primrec 
+  sum_below_0    "sum_below f 0 = 0"
+  sum_below_Suc  "sum_below f (Suc n) = f(n) + sum_below f n"
+
 end