English

A note on large Kakeya sets

Combinatorics 2020-03-20 v1

Abstract

A Kakeya set K\mathcal{K} in an affine plane of order qq is the point set covered by a set L\mathcal{L} of q+1q+1 pairwise non-parallel lines. Large Kakeya sets were studied by Dover and Mellinger; in [6] they showed that Kakeya sets with size at least q23q+9q^2-3q+9 contain a large knot (a point of K\mathcal{K} lying on many lines of L\mathcal{L}). In this paper, we improve on this result by showing that Kakeya set of size at least q2qq+32q\approx q^2-q\sqrt{q}+\frac{3}{2}q contain a large knot. Furthermore, we obtain a sharp result for planes of square order containing a Baer subplane.

Keywords

Cite

@article{arxiv.2003.08480,
  title  = {A note on large Kakeya sets},
  author = {Maarten De Boeck and Geertrui Van de Voorde},
  journal= {arXiv preprint arXiv:2003.08480},
  year   = {2020}
}

Comments

To appear in Advances in Geometry