Best possible lower bounds on the coefficients of Ehrhart polynomials

Abstract

For an integral convex polytope $\mathcal{P} \subset \mathbb{R}^d$, we recall $L_\mathcal{P}(n)=|n\mathcal{P} \cap \mathbb{Z}^d|$ the Ehrhart polynomial of $\mathcal{P}$. Let $g_r(\mathcal{P})$ be the $r$th coefficients of $L_\mathcal{P}(n)$ for $r=0,\ldots,d$. Martin Henk and Makoto Tagami gave lower bounds on the coefficients $g_r(\mathcal{P})$ in terms of the volume of $\mathcal{P}$. They proved that these bounds are best possible for $r \in \{1,2,d-2\}$. We show that these bounds are also optimal for $r=3$ and $d-r$ even and we give a new best possible bound for $r=d-3$.