diff -r 6e2479089226 -r cecd7a941885 ProgTutorial/Recipes/USTypes.thy
--- a/ProgTutorial/Recipes/USTypes.thy	Tue May 14 16:59:53 2019 +0200
+++ b/ProgTutorial/Recipes/USTypes.thy	Tue May 14 17:10:47 2019 +0200
@@ -4,7 +4,7 @@
 begin
 
 
-section {* User Space Type-Systems (TBD) *}
+section \<open>User Space Type-Systems (TBD)\<close>