Unavoidable patterns in complete simple topological graphs

Abstract

We show that every complete $n$-vertex simple topological graph contains a topological subgraph on at least $(\log n)^{1/4 - o(1)}$ vertices that is weakly isomorphic to the complete convex geometric graph or the complete twisted graph. This is the first improvement on the bound $\Omega(\log^{1/8}n)$ obtained in 2003 by Pach, Solymosi, and T\'oth. We also show that every complete $n$-vertex simple topological graph contains a plane path of length at least $(\log n)^{1 -o(1)}$.