Toward the Rectilinear Crossing Number of $K_n$: New Drawings, Upper Bounds, and Asymptotics

TL;DR

This paper advances understanding of the rectilinear crossing number of complete graphs by constructing optimal and near-optimal drawings, providing new bounds, asymptotic results, and discussing open problems in graph embedding.

Contribution

It introduces new rectilinear drawings of K_n with minimal crossings, improves upper bounds, and explores asymptotic behavior and open problems in the field.

Findings

Constructed rectilinear drawings with minimal crossings

Established improved asymptotic bounds for K_n

Presented new infinite families of drawings with good properties

Abstract

Scheinerman and Wilf (1994) assert that `an important open problem in the study of graph embeddings is to determine the rectilinear crossing number of the complete graph K_n.' A rectilinear drawing of K_n is an arrangement of n vertices in the plane, every pair of which is connected by an edge that is a line segment. We assume that no three vertices are collinear, and that no three edges intersect in a point unless that point is an endpoint of all three. The rectilinear crossing number of K_n is the fewest number of edge crossings attainable over all rectilinear drawings of K_n. For each n we construct a rectilinear drawing of K_n that has the fewest number of edge crossings and the best asymptotics known to date. Moreover, we give some alternative infinite families of drawings of K_n with good asymptotics. Finally, we mention some old and new open problems.