Chromatic Quasisymmetric Function Evaluated at q=-1

Abstract

Shareshian and Wachs have shown that the chromatic quasisymmetric function of the natural unit interval graph is symmetric (Shareshian--Wachs, 2016). In this thesis, we prove that the chromatic quasisymmetric function of any unit interval graph is symmetric at q=-1, and present a combinatorial interpretation of it in the Schur expansion.