Graphs with Two Crossings Are 5-Choosable
Zdenĕk Dvořák, Bernard Lidický, Riste Škrekovski · SIAM Journal on Discrete Mathematics · 2011
A graph G is k-choosable if G can be properly colored whenever every vertex has a list of at least k available colors. Thomassen's theorem states that every planar graph is 5-choosable. We extend the result by showing that every graph with at most two crossings is 5-choosable.