--- a/CookBook/Solutions.thy	Fri Mar 13 16:57:16 2009 +0100
+++ b/CookBook/Solutions.thy	Sat Mar 14 00:48:22 2009 +0100
@@ -79,7 +79,7 @@
 
 text {* The setup for the simproc is *}
 
-simproc_setup add_sp ("t1 + t2") = {* K add_sp_aux *}
+simproc_setup %gray add_sp ("t1 + t2") = {* K add_sp_aux *}
  
 text {* and a test case is the lemma *}