English

There are many 5-holes

Combinatorics 2026-03-20 v1

Abstract

Given a set P of points on the plane, a polygon with vertices in P is said to be empty if it contains no element of P in its interior. We show that every set of n points in general position on the plane determines at least Ω(n20/11)\Omega(n^{20/11}) empty convex pentagons (also known as 5-holes). This result improves upon the previous bound of Ω(n(logn)4/5)\Omega(n\cdot(\log n)^{4/5}) obtained by Aicholzer et al. [JCT A, 2020], and significantly narrows the gap with respect to the conjectured Ω(n2)\Omega(n^2) lower bound (which, if true, would be tight). Unlike some of the other works in this line of research, our proof does not require computer assistance.

Keywords

Cite

@article{arxiv.2603.18484,
  title  = {There are many 5-holes},
  author = {Omar Astudillo-Marbán and Oriol Solé-Pi},
  journal= {arXiv preprint arXiv:2603.18484},
  year   = {2026}
}

Comments

17 pages, 11 figures

R2 v1 2026-07-01T11:27:27.889Z