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Autore principale: Zhao, Tianchen
Natura: Preprint
Pubblicazione: 2025
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Accesso online:https://arxiv.org/abs/2511.21648
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author Zhao, Tianchen
author_facet Zhao, Tianchen
contents Let $X$ be a K3 or Enriques surface with good reduction. Let $G$ be a finite group acting (not necessarily linearly) on $X$. We give a criterion for this group action to extend to a smooth model of $X$ in terms of the action of $G$ on the second $\ell$-adic cohomology groups. In particular, we generalize the result on the extendability of Galois actions on K3 surfaces by Chiarellotto, Lazda, and Liedtke. As an application, we prove that a symplectic linear group action is extendable if the residue characteristic does not divide its order. Lastly, we relate the good reduction of Enriques surfaces with that of their K3 double covers.
format Preprint
id arxiv_https___arxiv_org_abs_2511_21648
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Extendability of group actions on K3 or Enriques surfaces
Zhao, Tianchen
Number Theory
Algebraic Geometry
11G25
Let $X$ be a K3 or Enriques surface with good reduction. Let $G$ be a finite group acting (not necessarily linearly) on $X$. We give a criterion for this group action to extend to a smooth model of $X$ in terms of the action of $G$ on the second $\ell$-adic cohomology groups. In particular, we generalize the result on the extendability of Galois actions on K3 surfaces by Chiarellotto, Lazda, and Liedtke. As an application, we prove that a symplectic linear group action is extendable if the residue characteristic does not divide its order. Lastly, we relate the good reduction of Enriques surfaces with that of their K3 double covers.
title Extendability of group actions on K3 or Enriques surfaces
topic Number Theory
Algebraic Geometry
11G25
url https://arxiv.org/abs/2511.21648