Quotient singularities in the Grothendieck ring of varieties

Fuente: arXiv
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Autori principali: Esser, Louis, Scavia, Federico
Natura: Preprint
Pubblicazione: 2022
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author Esser, Louis
Scavia, Federico
author_facet Esser, Louis
Scavia, Federico
contents Let $G$ be a finite group, $X$ be a smooth complex projective variety with a faithful $G$-action, and $Y$ be a resolution of singularities of $X/G$. Larsen and Lunts asked whether $[X/G]-[Y]$ is divisible by $[\mathbb{A}^1]$ in the Grothendieck ring of varieties. We show that the answer is negative if $BG$ is not stably rational and affirmative if $G$ is abelian. The case when $X=Z^n$ for some smooth projective variety $Z$ and $G=S_n$ acts by permutation of the factors is of particular interest. We make progress on it by showing that $[Z^n/S_n]-[Z\langle n\rangle / S_n]$ is divisible by $[\mathbb{A}^1]$, where $Z\langle n\rangle$ is Ulyanov's polydiagonal compactification of the $n$-th configuration space of $Z$.
format Preprint
id arxiv_https___arxiv_org_abs_2208_14313
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Quotient singularities in the Grothendieck ring of varieties
Esser, Louis
Scavia, Federico
Algebraic Geometry
14L30, 14E05, 14M20
Let $G$ be a finite group, $X$ be a smooth complex projective variety with a faithful $G$-action, and $Y$ be a resolution of singularities of $X/G$. Larsen and Lunts asked whether $[X/G]-[Y]$ is divisible by $[\mathbb{A}^1]$ in the Grothendieck ring of varieties. We show that the answer is negative if $BG$ is not stably rational and affirmative if $G$ is abelian. The case when $X=Z^n$ for some smooth projective variety $Z$ and $G=S_n$ acts by permutation of the factors is of particular interest. We make progress on it by showing that $[Z^n/S_n]-[Z\langle n\rangle / S_n]$ is divisible by $[\mathbb{A}^1]$, where $Z\langle n\rangle$ is Ulyanov's polydiagonal compactification of the $n$-th configuration space of $Z$.
title Quotient singularities in the Grothendieck ring of varieties
topic Algebraic Geometry
14L30, 14E05, 14M20
url https://arxiv.org/abs/2208.14313