English

Finding cliques and dense subgraphs using edge queries

Combinatorics 2024-07-12 v2 Discrete Mathematics

Abstract

We consider the problem of finding a large clique in an Erd\H{o}s--R\'enyi random graph where we are allowed unbounded computational time but can only query a limited number of edges. Recall that the largest clique in GG(n,1/2)G \sim G(n,1/2) has size roughly 2log2n2\log_{2} n. Let α(δ,)\alpha_{\star}(\delta,\ell) be the supremum over α\alpha such that there exists an algorithm that makes nδn^{\delta} queries in total to the adjacency matrix of GG, in a constant \ell number of rounds, and outputs a clique of size αlog2n\alpha \log_{2} n with high probability. We give improved upper bounds on α(δ,)\alpha_{\star}(\delta,\ell) for every δ[1,2)\delta \in [1,2) and 3\ell \geq 3. We also study analogous questions for finding subgraphs with density at least η\eta for a given η\eta, and prove corresponding impossibility results.

Keywords

Cite

@article{arxiv.2310.06826,
  title  = {Finding cliques and dense subgraphs using edge queries},
  author = {Endre Csóka and András Pongrácz},
  journal= {arXiv preprint arXiv:2310.06826},
  year   = {2024}
}

Comments

19 pp, 5 figures, Focused Workshop on Networks and Their Limits held at the Erd\H{o}s Center, Budapest, Hungary in July 2023

R2 v1 2026-06-28T12:46:12.544Z