diff -r c02171c5fb20 -r 59570adf2d3c src/HOL/HOL.ML
--- a/src/HOL/HOL.ML	Thu Oct 19 21:20:07 2000 +0200
+++ b/src/HOL/HOL.ML	Thu Oct 19 21:20:53 2000 +0200
@@ -32,6 +32,6 @@
 end;
 
 AddXIs [equal_intr_rule, disjI1, disjI2, ext];
-AddXEs [ex1_implies_ex, someI_ex];
+AddXEs [ex1_implies_ex, someI_ex, sym];
 
 open HOL;