Eulerian quasisymmetric functions for the type B Coxeter group and other wreath product groups

TL;DR

This paper generalizes Eulerian quasisymmetric functions to colored permutations within wreath product groups, deriving new generating functions and distribution formulas that extend previous results for symmetric groups.

Contribution

It introduces colored Eulerian quasisymmetric functions for wreath product groups and derives their generating functions, extending prior work on symmetric groups.

Findings

Derived a generating function formula for colored Eulerian quasisymmetric functions.

Extended Shareshian and Wachs' q-analog formulas to wreath product groups.

Provided formulas for joint distributions of colored permutation statistics.

Abstract

Eulerian quasisymmetric functions were introduced by Shareshian and Wachs in order to obtain a q-analog of Euler's exponential generating function formula for the Eulerian numbers. They are defined via the symmetric group, and applying the stable and nonstable principal specializations yields formulas for joint distributions of permutation statistics. We consider the wreath product of the cyclic group with the symmetric group, also known as the group of colored permutations. We use this group to introduce colored Eulerian quasisymmetric functions, which are a generalization of Eulerian quasisymmetric functions. We derive a formula for the generating function of these colored Eulerian quasisymmetric functions, which reduces to a formula of Shareshian and Wachs for the Eulerian quasisymmetric functions. We show that applying the stable and nonstable principal specializations yields formulas for joint distributions of colored permutation statistics, which generalize the Shareshian-Wachs q-analog of Euler's formula, formulas of Foata and Han, and a formula of Chow and Gessel.