Abstracts for the Seminar
 Discrete Geometry and Combinatorics
 Spring 2022

Speaker:  Jesse Selover, UMass Amherst
Title: On the Newton Polytopes of Chromatic Symmetric Functions
Time: 2:30 PM, Monday, April 18, 2022
Place:  Zoom

Abstract: The chromatic symmetric function, introduced by Stanley, is a well-studied generalization of the chromatic polynomial of a graph. Chromatic symmetric functions of (3+1)-free incomparability graphs (in particular, incomparability graphs of unit interval orders) are of particular interest. Motivated by the Stanley-Stembridge conjecture that such chromatic functions are e-positive, we show that the allowable coloring weights for such a graph are the lattice points of a permutahedron, and give a formula for the dominant coloring weight. We also give conjectures about convexity properties of these symmetric functions, and prove that they are Lorentzian in the abelian case. This is joint work with Alejandro Morales and Jacob Matherne.

Back to main seminar page.