diff -r c9f2e0c7359a -r 59addced5e2a CollectionUtils.m
--- a/CollectionUtils.m	Tue Apr 15 18:02:40 2008 -0700
+++ b/CollectionUtils.m	Fri May 02 12:49:43 2008 -0700
@@ -161,7 +161,9 @@
 
 
 
+
 @implementation NSSet (MYUtils)
+
 + (NSSet*) my_unionOfSet: (NSSet*)set1 andSet: (NSSet*)set2
 {
     if( set1 == set2 || set2.count==0 )
@@ -175,6 +177,19 @@
     }
 }
 
++ (NSSet*) my_intersectionOfSet: (NSSet*)set1 andSet: (NSSet*)set2
+{
+    if( set1 == set2 || set1.count==0 )
+        return set1;
+    else if( set2.count==0 )
+        return set2;
+    else {
+        NSMutableSet *result = [set1 mutableCopy];
+        [result intersectSet: set2];
+        return [result autorelease];
+    }
+}
+
 + (NSSet*) my_differenceOfSet: (NSSet*)set1 andSet: (NSSet*)set2
 {
     if( set1.count==0 || set2.count==0 )
@@ -187,6 +202,7 @@
         return [result autorelease];
     }
 }
+
 @end