The \'{e}tale Brauer-Manin obstruction for classifying stacks
Number Theory
2026-04-17 v2 Algebraic Geometry
Abstract
We study the strong approximation for classifying stacks , where is a linear algebraic group over a number field . More specifically, we prove that the \'etale Brauer-Manin obstruction is the only obstruction to strong approximation for . To prove the result, we formulate the theory of torsors and Galois twists for algebraic stacks.
Keywords
Cite
@article{arxiv.2512.01014,
title = {The \'{e}tale Brauer-Manin obstruction for classifying stacks},
author = {Ajneet Dhillon and Nicole Lemire and Jonathan Martin and Yidi Wang},
journal= {arXiv preprint arXiv:2512.01014},
year = {2026}
}
Comments
15 pages; minor changes in Section 3. Comments welcome!