The choice number versus the chromatic number for graphs embeddable on orientable surfaces (Q2121742)

Summary: We show that for loopless \(6\)-regular triangulations on the torus the gap between the choice number and chromatic number is at most \(2\). We also show that the largest gap for graphs embeddable in an orientable surface of genus \(g\) is of the order \(\Theta(\sqrt{g})\), and moreover for graphs with chromatic number of the order \(o(\sqrt{g}/\log_2(g))\) the largest gap is of the order \(o(\sqrt{g})\).