English

Incidences between points and lines in R^4

Combinatorics 2015-03-26 v2

Abstract

We show that the number of incidences between mm distinct points and nn distinct lines in R4{\mathbb R}^4 is O(2clogm(m2/5n4/5+m)+m1/2n1/2q1/4+m2/3n1/3s1/3+n)O\left(2^{c\sqrt{\log m}} (m^{2/5}n^{4/5}+m) + m^{1/2}n^{1/2}q^{1/4} + m^{2/3}n^{1/3}s^{1/3} + n\right), for a suitable absolute constant cc, provided that no 2-plane contains more than ss input lines, and no hyperplane or quadric contains more than qq lines. The bound holds without the factor 2clogm2^{c\sqrt{\log m}} when mn6/7m \le n^{6/7} or mn5/3m \ge n^{5/3}. Except for this factor, the bound is tight in the worst case.

Keywords

Cite

@article{arxiv.1411.0777,
  title  = {Incidences between points and lines in R^4},
  author = {Micha Sharir and Noam Solomon},
  journal= {arXiv preprint arXiv:1411.0777},
  year   = {2015}
}
R2 v1 2026-06-22T06:47:02.130Z