On the Density of non-Simple 3-Planar Graphs

Michael A. Bekos, Michael Kaufmann, Chrysanthi N. Raftopoulou

A \emph{$k$-planar graph} is a graph that can be drawn in the plane such that every edge is crossed at most $k$ times. For $k\le 4$, Pach and Tóth proved a bound of $(k+3)(n-2)$…