Succinct filters for sets of unknown sizes

Mingmou Liu, Yitong Yin, Huacheng Yu

Research output: Chapter in Book/Report/Conference proceedingConference contribution

9 Scopus citations


The membership problem asks to maintain a set S ⊆ [u], supporting insertions and membership queries, i.e., testing if a given element is in the set. A data structure that computes exact answers is called a dictionary. When a (small) false positive rate ε is allowed, the data structure is called a filter. The space usages of the standard dictionaries or filters usually depend on the upper bound on the size of S, while the actual set can be much smaller. Pagh, Segev and Wieder [28] were the first to study filters with varying space usage based on the current |S|. They showed in order to match the space with the current set size n = |S|, any filter data structure must use (1 − o(1))n(log(1/ε) + (1 − O(ε)) log log n) bits, in contrast to the well-known lower bound of N log(1/ε) bits, where N is an upper bound on |S|. They also presented a data structure with almost optimal space of (1 + o(1))n(log(1/ε) + O(log log n)) bits provided that n > u0.001, with expected amortized constant insertion time and worst-case constant lookup time. In this work, we present a filter data structure with improvements in two aspects: it has constant worst-case time for all insertions and lookups with high probability; it uses space (1 + o(1))n(log(1/ε) + log log n) bits when n > u0.001, achieving optimal leading constant for all ε = o(1). We also present a dictionary that uses (1 + o(1))n log(u/n) bits of space, matching the optimal space in terms of the current size, and performs all operations in constant time with high probability.

Original languageEnglish (US)
Title of host publication47th International Colloquium on Automata, Languages, and Programming, ICALP 2020
EditorsArtur Czumaj, Anuj Dawar, Emanuela Merelli
PublisherSchloss Dagstuhl- Leibniz-Zentrum fur Informatik GmbH, Dagstuhl Publishing
ISBN (Electronic)9783959771382
StatePublished - Jun 1 2020
Event47th International Colloquium on Automata, Languages, and Programming, ICALP 2020 - Virtual, Online, Germany
Duration: Jul 8 2020Jul 11 2020

Publication series

NameLeibniz International Proceedings in Informatics, LIPIcs
ISSN (Print)1868-8969


Conference47th International Colloquium on Automata, Languages, and Programming, ICALP 2020
CityVirtual, Online

All Science Journal Classification (ASJC) codes

  • Software


  • Approximate set membership
  • Bloom filters
  • Data structures
  • Dictionaries


Dive into the research topics of 'Succinct filters for sets of unknown sizes'. Together they form a unique fingerprint.

Cite this