diff -r 65d18005d802 -r 9e888d60d3e5 doc-src/TutorialI/Rules/Primes.thy
--- a/doc-src/TutorialI/Rules/Primes.thy	Fri Jan 05 18:32:33 2001 +0100
+++ b/doc-src/TutorialI/Rules/Primes.thy	Fri Jan 05 18:32:57 2001 +0100
@@ -84,7 +84,7 @@
   done;
 
 theorem gcd_greatest_iff [iff]: 
-        "k dvd gcd(m,n) = (k dvd m \<and> k dvd n)"
+        "(k dvd gcd(m,n)) = (k dvd m \<and> k dvd n)"
   apply (blast intro!: gcd_greatest intro: dvd_trans);
   done;