Essential dimension of cohomology classes via valuation theory

Fuente: arXiv
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Autores principales: Ofek, Danny, Reichstein, Zinovy
Formato: Preprint
Publicado: 2024
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author Ofek, Danny
Reichstein, Zinovy
author_facet Ofek, Danny
Reichstein, Zinovy
contents We give a formula for the essential dimension of a cohomology class $α$ in $H^d(K, \mathbb{Q}_p/\mathbb{Z}_p (d))$ when $K$ is a strictly Henselian field. This formula is particularly explicit in the case, where $α$ is a Brauer class (for $d = 2$). As an application of our bound with $d = 3$, we study the essential dimension of exceptional groups by examining the image of the Rost invariant.
format Preprint
id arxiv_https___arxiv_org_abs_2401_08532
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Essential dimension of cohomology classes via valuation theory
Ofek, Danny
Reichstein, Zinovy
Group Theory
Commutative Algebra
K-Theory and Homology
12G05, 12J20, 16K50, 19C30
We give a formula for the essential dimension of a cohomology class $α$ in $H^d(K, \mathbb{Q}_p/\mathbb{Z}_p (d))$ when $K$ is a strictly Henselian field. This formula is particularly explicit in the case, where $α$ is a Brauer class (for $d = 2$). As an application of our bound with $d = 3$, we study the essential dimension of exceptional groups by examining the image of the Rost invariant.
title Essential dimension of cohomology classes via valuation theory
topic Group Theory
Commutative Algebra
K-Theory and Homology
12G05, 12J20, 16K50, 19C30
url https://arxiv.org/abs/2401.08532