diff -r 2c585bb9560c -r 995162143ef4 src/Pure/General/linear_set.scala
--- a/src/Pure/General/linear_set.scala	Thu Feb 20 14:17:28 2014 +0100
+++ b/src/Pure/General/linear_set.scala	Thu Feb 20 14:36:17 2014 +0100
@@ -8,6 +8,7 @@
 
 package isabelle
 
+
 import scala.collection.SetLike
 import scala.collection.generic.{ImmutableSetFactory, CanBuildFrom,
   GenericSetTemplate, GenericCompanion}