Extremal structure in dense arrangements of $k$-intersecting curves
Combinatorics
2026-05-21 v1
Abstract
Let be a set of points in the plane, and let be a collection of simple -intersecting curves, meaning that every two distinct curves of meet in at most points. A classical theorem of Pach and Sharir from 1998 gives the upper bound . We prove that this bound can be improved when one excludes a complete local incidence pattern. More precisely, for any fixed integers , if there do not exist points of such that every -tuple among them is contained in a distinct curve of , then . In the special case of pseudo-segments, this extends Solymosi's theorem on dense point-line arrangements to dense arrangements of pseudo-segments.
Keywords
Cite
@article{arxiv.2605.20705,
title = {Extremal structure in dense arrangements of $k$-intersecting curves},
author = {Andrew Suk and Su Zhou},
journal= {arXiv preprint arXiv:2605.20705},
year = {2026}
}