[magicalhippo]

The article states a Bloom filter is "guaranteed to report correctly if it contains the item", however a Bloom filter cannot do this. The bits set by the various hash functions could very well be set due to some other key. What the Bloom filter _can_ say, is that if none of the bits are set, then clearly the key was never inserted.

[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.

[kata]

I think it might just be a strangely formed sentence where the part "if it contains the item" is not the subject of the report, but a condition:

If it contains the item -> reports that it contains the item (correctly)

If it doesn't contain the item -> may report that it contains the item (incorrectly)

[kakarot]

Nothing wrong with being pedantic when dealing with definitions.

[egocentric]

Since we're on the topic of being pedantic, "well, you know, that's just, like... your opinion, man". I'd argue that there's nothing excessive about arguing if A may, in fact, be the opposite of A :)

[kakarot]

Certainly not, I'm all for some arguing on the internet.

[magicalhippo]

The logic you wrote is exactly the _opposite_ of what a Bloom filter does.