Pak–Stanley labeling for central graphical arrangements

Abstract

The original Pak-Stanley labeling was defined by Pak and Stanley as a bijective map from the set of regions of an extended Shi arrangement to the set of parking functions. This map was later generalized to other arrangements associated with graphs and directed multigraphs. In these more general cases the map is no longer bijective. However, it was shown Hopkins and Perkinson and then the first author that it is surjective to the set of the $G$-parking functions, where $G$ is the multigraph associated with the arrangement. This leads to a natural question: when is the generalized Pak-Stanley map bijective? In this paper we answer this question in the special case of centered hyperplane arrangements, i.e. the case when all the hyperplanes of the arrangement pass through a common point.