Arash Partow wrote:

Phil Endecott wrote:

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Sorry Arash but I don't understand your reply; what exactly is correct?

My point was that you are correct, the "and" does not provide anything of value. Only "or" and "xor" are practical for non-counting bloom filters.

Well no, that's not what I said. For clarity, I believe that: 1. Bitwise OR of two bloom filters achieves the set union without any side effects. 2. Bitwise AND of two bloom filters achieves the set intersection, but it will introduce additional false positives, which may or may not be acceptable since they are already inherent in bloom filters. 3. Bitwise XOR of two bloom filters achieves something like the set symetric difference, but will introduce false negatives, which probably are not acceptable because bloom filters do not otherwise suffer from them.

I'm not sure what you mean by overlapping hashes

I simply mean the case where two distinct values have the same hash for some of the hash functions. Regards, Phil.