diff -r 5ab1746186c7 -r 5b2a7caa855b src/HOL/Corec_Examples/Tests/Merge_D.thy
--- a/src/HOL/Corec_Examples/Tests/Merge_D.thy	Mon Mar 28 12:05:47 2016 +0200
+++ b/src/HOL/Corec_Examples/Tests/Merge_D.thy	Mon Mar 28 12:05:47 2016 +0200
@@ -6,7 +6,7 @@
 Tests theory merges.
 *)
 
-section {* Tests Theory Merges *}
+section \<open>Tests Theory Merges\<close>
 
 theory Merge_D
 imports Merge_B Merge_C