diff -r 4939494ed791 -r ce654b0e6d69 src/HOL/MicroJava/JVM/JVMExec.thy
--- a/src/HOL/MicroJava/JVM/JVMExec.thy	Tue Feb 13 14:24:50 2018 +0100
+++ b/src/HOL/MicroJava/JVM/JVMExec.thy	Thu Feb 15 12:11:00 2018 +0100
@@ -25,7 +25,7 @@
 
 definition exec_all :: "[jvm_prog,jvm_state,jvm_state] => bool"
               ("_ \<turnstile> _ \<midarrow>jvm\<rightarrow> _" [61,61,61]60) where
-  "G \<turnstile> s \<midarrow>jvm\<rightarrow> t == (s,t) \<in> {(s,t). exec(G,s) = Some t}^*"
+  "G \<turnstile> s \<midarrow>jvm\<rightarrow> t == (s,t) \<in> {(s,t). exec(G,s) = Some t}\<^sup>*"
 
 
 text \<open>