Bounded powers of edge ideals: Gorenstein toric rings

Let $S=K[x_1,\dots ,x_n]$ denote the polynomial ring in $n$ variables over a field $K$ and $I\subset S$ a monomial ideal. Given a vector $\mathfrak{c}\in {\mathbb{N}}^n$, the ideal $I_{\mathfrak{c}}$ is the ideal generated by those monomials belonging to $I$ whose exponent vectors are componentwise bounded above by $\mathfrak{c}$. Let ${\delta }_{\mathfrak{c}}(I)$ be the largest integer $q$ for which $(I^q{)}_{\mathfrak{c}}\mathrm{\ne }0$. For a finite graph $G$, its edge ideal is denoted by $I(G)$. Let $\mathcal{B}(\mathfrak{c},G)$ be the toric ring which is generated by the monomials belonging to the minimal system of monomial generators of $(I(G{)}^{{\delta }_{\mathfrak{c}}(I)}{)}_{\mathfrak{c}}$. In a previous work, the authors proved that $(I(G{)}^{{\delta }_{\mathfrak{c}}(I)}{)}_{\mathfrak{c}}$ is a polymatroidal ideal. It follows that $\mathcal{B}(\mathfrak{c},G)$ is a normal Cohen–Macaulay domain. In this paper, we study the Gorenstein property of $\mathcal{B}(\mathfrak{c},G)$.