Approximate Triangle Counting via Sampling and Fast Matrix Multiplication

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There is a simple (equation presented) time algorithm for 1±ϵ-approximate triangle counting where T is the number of triangles in the graph and n the number of vertices. At the same time, one may count triangles exactly using fast matrix multiplication in time Õ(nω). Is it possible to get a negative dependency on the number of triangles T while retaining the state-of-the-art nω dependency on n? We answer this question positively by providing an algorithm which runs in time (equation presented). This is optimal in the sense that as long as the exponent of T is independent of n, T, it cannot be improved while retaining the dependency on n. Our algorithm improves upon the state of the art when T ≫ 1 and T ≪ n. We also consider the problem of approximate triangle counting in sparse graphs, parameterized by the number of edges m. The best known algorithm runs in time (equation presented) [Eden et al., SIAM Journal on Computing, 2017]. An algorithm by Alon et al. [JACM, 1995] for exact triangle counting that runs in time (equation presented). We again get an algorithm whose complexity has a state-of-the-art dependency on m while having negative dependency on T. Specifically, our algorithm runs in time (equation presented). This is again optimal in the sense that no better constant exponent of T is possible without worsening the dependency on m. This algorithm improves upon the state of the art when T ≫ 1 and T ≪ √m. In both cases, algorithms with time complexity matching query complexity lower bounds were known on some range of parameters. While those algorithms have optimal query complexity for the whole range of T, the time complexity departs from the query complexity and is no longer optimal (as we show) for T ≪ n and T ≪ √m, respectively. We focus on the time complexity in this range of T. To the best of our knowledge, this is the first paper considering the discrepancy between query and time complexity in graph parameter estimation.

Original languageEnglish
Title of host publication49th EATCS International Conference on Automata, Languages, and Programming, ICALP 2022
EditorsMikolaj Bojanczyk, Emanuela Merelli, David P. Woodruff
Number of pages20
PublisherSchloss Dagstuhl- Leibniz-Zentrum fur Informatik GmbH, Dagstuhl Publishing
Publication date2022
Article number107
ISBN (Electronic)9783959772358
DOIs
Publication statusPublished - 2022
Event49th EATCS International Conference on Automata, Languages, and Programming, ICALP 2022 - Paris, France
Duration: 4 Jul 20228 Jul 2022

Conference

Conference49th EATCS International Conference on Automata, Languages, and Programming, ICALP 2022
LandFrance
ByParis
Periode04/07/202208/07/2022
SponsorCNRS, Inria, Nomadic Lab, Université Paris Cité
SeriesLeibniz International Proceedings in Informatics, LIPIcs
Volume229
ISSN1868-8969

Bibliographical note

Publisher Copyright:
© Jakub Tětek; licensed under Creative Commons License CC-BY 4.0

    Research areas

  • Approximate triangle counting, Fast matrix multiplication, Sampling

ID: 342672660