English

Maximal independent sets in clique-free graphs

Combinatorics 2021-08-17 v1

Abstract

Nielsen proved that the maximum number of maximal independent sets (MIS's) of size kk in an nn-vertex graph is asymptotic to (n/k)k(n/k)^k, with the extremal construction a disjoint union of kk cliques with sizes as close to n/kn/k as possible. In this paper we study how many MIS's of size kk an nn-vertex graph GG can have if GG does not contain a clique KtK_t. We prove for all fixed kk and tt that there exist such graphs with n(t2)kt1o(1)n^{\lfloor\frac{(t-2)k}{t-1}\rfloor-o(1)} MIS's of size kk by utilizing recent work of Gowers and B. Janzer on a generalization of the Ruzsa-Szemer\'edi problem. We prove that this bound is essentially best possible for triangle-free graphs when k4k\le 4.

Keywords

Cite

@article{arxiv.2108.06359,
  title  = {Maximal independent sets in clique-free graphs},
  author = {Xiaoyu He and Jiaxi Nie and Sam Spiro},
  journal= {arXiv preprint arXiv:2108.06359},
  year   = {2021}
}

Comments

18 pages

R2 v1 2026-06-24T05:06:15.580Z