Nearly Optimal Local Algorithms for Constructing Sparse Spanners of Clusterable Graphs

Reut Levi, Moti Medina, Omer Tubul

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

In this paper, we study the problem of locally constructing a sparse spanning subgraph (LSSG), introduced by Levi, Ron, and Rubinfeld (ALGO’20). In this problem, the goal is to locally decide for each e ∈ E if it is in G where G is a connected subgraph of G (determined only by G and the randomness of the algorithm). We provide an LSSG that receives as a parameter a lower bound, ϕ, on the conductance of G whose query complexity is Õ(√n/ϕ2). This is almost optimal when ϕ is a constant since Ω(√n) queries are necessary even when G is an expander. Furthermore, this improves the state of the art of Õ(n2/3) queries for ϕ = Ω(1/n1/12). We then extend our result for (k, ϕin, ϕout)-clusterable graphs and provide an algorithm whose query complexity is Õ(√n + ϕoutn) for constant k and ϕin. This bound is almost optimal when ϕout = O(1/√n).

Original languageEnglish
Title of host publicationApproximation, Randomization, and Combinatorial Optimization. Algorithms and Techniques, APPROX/RANDOM 2024
EditorsAmit Kumar, Noga Ron-Zewi
PublisherSchloss Dagstuhl- Leibniz-Zentrum fur Informatik GmbH, Dagstuhl Publishing
ISBN (Electronic)9783959773485
DOIs
StatePublished - Sep 2024
Event27th International Conference on Approximation Algorithms for Combinatorial Optimization Problems, APPROX 2024 and the 28th International Conference on Randomization and Computation, RANDOM 2024 - London, United Kingdom
Duration: 28 Aug 202430 Aug 2024

Publication series

NameLeibniz International Proceedings in Informatics, LIPIcs
Volume317
ISSN (Print)1868-8969

Conference

Conference27th International Conference on Approximation Algorithms for Combinatorial Optimization Problems, APPROX 2024 and the 28th International Conference on Randomization and Computation, RANDOM 2024
Country/TerritoryUnited Kingdom
CityLondon
Period28/08/2430/08/24

Bibliographical note

Publisher Copyright:
© Reut Levi, Moti Medina, and Omer Tubul.

Keywords

  • Clusterbale Graphs
  • Locally Computable Algorithms
  • Spanning Subgraphs
  • Sublinear algorithms

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