Measuring the non-Gorenstein locus of Hibi rings and normal affine semigroup rings
arXiv:1903.05847 · doi:10.1016/j.jalgebra.2019.08.028
Abstract
The trace of the canonical module of a Cohen-Macaulay ring describes its non-Gorenstein locus. We study the trace of the canonical module of a Segre product of algebras, and we apply our results to compute the non-Gorenstein locus of toric rings. We provide several sufficient and necessary conditions for Hibi rings and normal semigroup rings to be Gorenstein on the punctured spectrum.