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Bibliographic Details
Main Author: Monnet, Sebastian
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2502.08723
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author Monnet, Sebastian
author_facet Monnet, Sebastian
contents Let $X$ be a K3 surface defined over a number field $k$, with principal complex multiplication by a CM field $E$. We find explicit bounds, in terms of $k$ and $E$, on the size of the transcendental Brauer group $\operatorname{Br}(X)/\operatorname{Br}_1(X)$ of $X$. Bounding the size of this group is important for computing the Brauer--Manin obstruction, which is conjectured by Skorobogatov to be the only obstruction to the Hasse principle for K3 surfaces. Our methods are built on top of earlier work by Valloni, who related the group $\operatorname{Br}(X)/\operatorname{Br}_1(X)$ to the arithmetic structure of the CM field $E$. It is from this arithmetic structure that we deduce our bounds.
format Preprint
id arxiv_https___arxiv_org_abs_2502_08723
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Explicit bounds on the transcendental Brauer group of K3 surfaces with principal complex multiplication
Monnet, Sebastian
Number Theory
Let $X$ be a K3 surface defined over a number field $k$, with principal complex multiplication by a CM field $E$. We find explicit bounds, in terms of $k$ and $E$, on the size of the transcendental Brauer group $\operatorname{Br}(X)/\operatorname{Br}_1(X)$ of $X$. Bounding the size of this group is important for computing the Brauer--Manin obstruction, which is conjectured by Skorobogatov to be the only obstruction to the Hasse principle for K3 surfaces. Our methods are built on top of earlier work by Valloni, who related the group $\operatorname{Br}(X)/\operatorname{Br}_1(X)$ to the arithmetic structure of the CM field $E$. It is from this arithmetic structure that we deduce our bounds.
title Explicit bounds on the transcendental Brauer group of K3 surfaces with principal complex multiplication
topic Number Theory
url https://arxiv.org/abs/2502.08723