--- a/src/HOL/HOLCF/ex/Letrec.thy Wed Jan 13 23:02:28 2016 +0100
+++ b/src/HOL/HOLCF/ex/Letrec.thy Wed Jan 13 23:07:06 2016 +0100
@@ -2,7 +2,7 @@
Author: Brian Huffman
*)
-section {* Recursive let bindings *}
+section \<open>Recursive let bindings\<close>
theory Letrec
imports HOLCF