> 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

> 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.