English

Point-curve incidences in the complex plane

Combinatorics 2018-07-18 v4

Abstract

We prove an incidence theorem for points and curves in the complex plane. Given a set of mm points in R2{\mathbb R}^2 and a set of nn curves with kk degrees of freedom, Pach and Sharir proved that the number of point-curve incidences is O(mk2k1n2k22k1+m+n)O\big(m^{\frac{k}{2k-1}}n^{\frac{2k-2}{2k-1}}+m+n\big). We establish the slightly weaker bound Oε(mk2k1+εn2k22k1+m+n)O_\varepsilon\big(m^{\frac{k}{2k-1}+\varepsilon}n^{\frac{2k-2}{2k-1}}+m+n\big) on the number of incidences between mm points and nn (complex) algebraic curves in C2{\mathbb C}^2 with kk degrees of freedom. We combine tools from algebraic geometry and differential geometry to prove a key technical lemma that controls the number of complex curves that can be contained inside a real hypersurface. This lemma may be of independent interest to other researchers proving incidence theorems over C{\mathbb C}.

Keywords

Cite

@article{arxiv.1502.07003,
  title  = {Point-curve incidences in the complex plane},
  author = {Adam Sheffer and Endre Szabó and Joshua Zahl},
  journal= {arXiv preprint arXiv:1502.07003},
  year   = {2018}
}

Comments

The proof was significantly simplified, and now relies on the Picard-Lindelof theorem, rather than on foliations

R2 v1 2026-06-22T08:37:10.785Z