A $4$-choosable graph that is not $(8:2)$-choosable

Abstract

In 1980, Erdős, Rubin and Taylor asked whether for all positive integers $a$, $b$, and $m$, every $(a:b)$-choosable graph is also $(am:bm)$-choosable. We provide a negative answer by exhibiting a $4$-choosable graph that is not $(8:2)$-choosable.

References in corpus (1)

• Some results on (a:b)-choosability

Cited by in corpus (5)

• Fractional coloring with local demands and applications to degree-sequence bounds on the independence number
• Strong fractional choice number of series-parallel graphs
• Multiple list colouring of $3$-choice critical graphs
• A Note on Fractional DP-Coloring of Graphs
• Multiple list colouring triangle-free planar graphs