  Dvorak (2013) gave a bound on the minimum size of a distance r dominating set
in the terms of the maximum size of a distance 2r independent set and
generalized coloring numbers, thus obtaining a constant factor approximation
algorithm for the parameters in any class of graphs with bounded expansion. We
improve and clarify this dependence using an LP-based argument inspired by the
work of Bansal and Umboh (2017).
