[foota]

I wonder... The comparison here is against a bloom filter, but is this actually more similar to a sketch?

Or... Actually this is sort of like a posting list (e.g., a list of places that a given document appears: https://en.m.wikipedia.org/wiki/Inverted_index)

[esafak]

It's a probabilistic associative array. A better benchmark is a Bloomier filter: https://en.wikipedia.org/wiki/Bloom_filter#Bloomier_filters