diff -r 6f012a209dac -r c8a9eaaa2f59 src/HOL/Decision_Procs/Commutative_Ring.thy
--- a/src/HOL/Decision_Procs/Commutative_Ring.thy	Fri Oct 22 23:45:20 2010 +0200
+++ b/src/HOL/Decision_Procs/Commutative_Ring.thy	Sun Oct 24 20:19:00 2010 +0200
@@ -266,7 +266,7 @@
     proof cases
       assume "even l"
       then have "Suc l div 2 = l div 2"
-        by (simp add: nat_number even_nat_plus_one_div_two)
+        by (simp add: eval_nat_numeral even_nat_plus_one_div_two)
       moreover
       from Suc have "l < k" by simp
       with 1 have "\<And>P. Ipol ls (pow l P) = Ipol ls P ^ l" by simp