Abstract
We give a geometric description of the set of holes in a non-normal affine monoid Q. The set of holes turns out to be related to the non-trivial graded components of the local cohomology of \({\mathbb{K}[Q]}\). From this, we see how various properties of \({\mathbb{K}[Q]}\) like local normality and Serre’s conditions (R 1) and (S 2) are encoded in the geometry of the holes. A combinatorial upper bound for the depth the monoid algebra \({\mathbb{K}[Q]}\) is obtained which in some cases can be used to compute its depth.
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This work was supported by the DAAD.
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Katthän, L. Non-normal affine monoid algebras. manuscripta math. 146, 223–233 (2015). https://doi.org/10.1007/s00229-014-0685-7
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DOI: https://doi.org/10.1007/s00229-014-0685-7