Open Access Publications from the University of California

## Symmetric edge polytopes and matching generating polynomials

• Author(s): Ohsugi, Hidefumi;
• Tsuchiya, Akiyoshi
• et al.

## Published Web Location

https://doi.org/10.5070/C61055371
Abstract

Symmetric edge polytopes $\mathcal{A}_G$ of type A are lattice polytopes arising from the root system $A_n$ and finite simple graphs $G$. There is a connection between $\mathcal{A}_G$ and the Kuramoto synchronization model in physics. In particular, the normalized volume of $\mathcal{A}_G$ plays a central role. In the present paper, we focus on a particular class of graphs. In fact, for any cactus graph $G$, we give a formula for the $h^*$-polynomial of $\mathcal{A}_{\widehat{G}}$ by using matching generating polynomials, where $\widehat{G}$ is the suspension of $G$. This gives also a formula for the normalized volume of $\mathcal{A}_{\widehat{G}}$. Moreover, via methods from chemical graph theory, we show that for any cactus graph $G$, the $h^*$-polynomial of $\mathcal{A}_{\widehat{G}}$ is real-rooted. Finally, we extend the discussion to symmetric edge polytopes of type $B$, which are lattice polytopes arising from the root system $B_n$ and finite simple graphs.

Keywords: Symmetric edge polytope, $h^*$-polynomial, interior polynomial, matching generating polynomial, $\mu$-polynomial, real-rooted, $\gamma$-positive.

Mathematics Subject Classifications: 05A15, 05C31, 13P10, 52B12, 52B20