Rational singularities

Fuente: arXiv
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Main Author: Kovács, Sándor J
Format: Preprint
Published: 2017
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author Kovács, Sándor J
author_facet Kovács, Sándor J
contents A resolution-free definition of rational singularities is introduced, and it is proved that for a variety admitting a resolution of singularities, so in particular in characteristic zero, this is equivalent to the usual definition. It is also demonstrated that pseudo-rational singularities are rational. The main theorem, a Kempf-type criterion for rational singularities, is new even in characteristic zero contrasting an earlier result of Cutkosky that a similar result with slightly different assumptions could not hold. Several applications are included. In particular, an Elkik-type theorem, proving that Cohen-Macaulay dlt singularities are rational in arbitrary characteristic.
format Preprint
id arxiv_https___arxiv_org_abs_1703_02269
institution arXiv
publishDate 2017
record_format arxiv
spellingShingle Rational singularities
Kovács, Sándor J
Algebraic Geometry
A resolution-free definition of rational singularities is introduced, and it is proved that for a variety admitting a resolution of singularities, so in particular in characteristic zero, this is equivalent to the usual definition. It is also demonstrated that pseudo-rational singularities are rational. The main theorem, a Kempf-type criterion for rational singularities, is new even in characteristic zero contrasting an earlier result of Cutkosky that a similar result with slightly different assumptions could not hold. Several applications are included. In particular, an Elkik-type theorem, proving that Cohen-Macaulay dlt singularities are rational in arbitrary characteristic.
title Rational singularities
topic Algebraic Geometry
url https://arxiv.org/abs/1703.02269