src/HOL/BNF_GFP.thy

--- a/src/HOL/BNF_GFP.thy	Mon Jan 20 18:59:53 2014 +0100
+++ b/src/HOL/BNF_GFP.thy	Mon Jan 20 19:05:25 2014 +0100
@@ -10,7 +10,7 @@
 header {* Greatest Fixed Point Operation on Bounded Natural Functors *}
 
 theory BNF_GFP
-imports BNF_FP_Base List_Prefix
+imports BNF_FP_Base List_Prefix String
 keywords
   "codatatype" :: thy_decl and
   "primcorecursive" :: thy_goal and