Midrange crossing constants for graphs classes

Abstract

For positive integers $n$ and $e$, let $\kappa (n,e)$ be the minimum crossing number (the standard planar crossing number) taken over all graphs with $n$ vertices and at least $e$ edges. Pach, Spencer and Tóth [Discrete and Computational Geometry 24 623--644, (2000)] showed that $\kappa (n,e)n^2/e^3$ tends to a positive constant (called midrange crossing constant) as $n\to \infty$ and $n\ll e\ll n^2$, proving a conjecture of Erdős and Guy. In this note, we extend their proof to show that the midrange crossing constant exists for graph classes that satisfy a certain set of graph properties. As a corollary, we show that the the midrange crossing constant exists for the family of bipartite graphs. All these results have their analogues for rectilinear crossing numbers.