diff -r 98fc47533342 -r 47c9aff07725 src/HOL/Semiring_Normalization.thy
--- a/src/HOL/Semiring_Normalization.thy	Sun Aug 18 17:00:10 2013 +0200
+++ b/src/HOL/Semiring_Normalization.thy	Sun Aug 18 18:49:45 2013 +0200
@@ -107,7 +107,7 @@
   "(x ^ p) * (x ^ q) = x ^ (p + q)"
   "x * (x ^ q) = x ^ (Suc q)"
   "(x ^ q) * x = x ^ (Suc q)"
-  "x * x = x ^ 2"
+  "x * x = x\<^sup>2"
   "(x * y) ^ q = (x ^ q) * (y ^ q)"
   "(x ^ p) ^ q = x ^ (p * q)"
   "x ^ 0 = 1"