English

Disjoint edges in topological graphs and the tangled-thrackle conjecture

Combinatorics 2015-08-25 v2 Computational Geometry

Abstract

It is shown that for a constant tNt\in \mathbb{N}, every simple topological graph on nn vertices has O(n)O(n) edges if it has no two sets of tt edges such that every edge in one set is disjoint from all edges of the other set (i.e., the complement of the intersection graph of the edges is Kt,tK_{t,t}-free). As an application, we settle the \emph{tangled-thrackle} conjecture formulated by Pach, Radoi\v{c}i\'c, and T\'oth: Every nn-vertex graph drawn in the plane such that every pair of edges have precisely one point in common, where this point is either a common endpoint, a crossing, or a point of tangency, has at most O(n)O(n) edges.

Keywords

Cite

@article{arxiv.1406.2726,
  title  = {Disjoint edges in topological graphs and the tangled-thrackle conjecture},
  author = {Andres J. Ruiz-Vargas and Andrew Suk and Csaba D. Tóth},
  journal= {arXiv preprint arXiv:1406.2726},
  year   = {2015}
}