Ulrich elements in normal simplicial affine semigroups

Jürgen Herzog, Raheleh Jafari, Dumitru I. Stamate

Let $H\subseteq {\mathbb{N}}^d$ be a normal affine semigroup, $R=K[H]$ its semigroup ring over the field $K$ and ${\omega }_R$ its canonical module. The Ulrich elements for $H$ are those $h$…