# Zhu, Xuding

## Bounding the on-line choice number in terms of the choice number ★★

Author(s): Zhu

\begin{question} Are there graphs for which $\text{ch}^{\text{OL}}-\text{ch}$ is arbitrarily large? \end{question}

Keywords: choosability; list coloring; on-line choosability

## Circular coloring triangle-free subcubic planar graphs ★★

\begin{problem} Does every triangle-free planar graph of maximum degree three have circular chromatic number at most $\frac{20}{7}$? \end{problem}

Keywords: circular coloring; planar graph; triangle free