[ScottBurson]

> The article states a Bloom filter is "guaranteed to report correctly if it contains the item", however a Bloom filter cannot do this.

I think what's going on here is that you're reading "if" as meaning "whether". In fairness, this is common English usage: "I'll tell you tomorrow if I'm going" usually means "I'll tell you tomorrow whether I'm going".

That's not what the OP means. The correct reading is perhaps clarified with a comma:

> A Bloom filter is guaranteed to report correctly, if it contains the item.

or perhaps better

> If it contains the item, a Bloom filter is guaranteed to report correctly.

[magicalhippo]

Ah yes, that would be it.

IMO it is better to present the Bloom filter by asking/stating what one can be certain of given each return value of the Bloom filter.