Description of the strong approximation locus using Brauer-Manin obstruction for homogeneous spaces with commutative stabilizers
Abstract
For a homogeneous space over a number field , the Brauer-Manin obstruction has been used to study strong approximation for away from a finite set of places, and known results state that is dense in the omitting- projection of the Brauer-Manin set , under certain assumptions. In order to completely understand the closure of in the set of -adelic points , we ask: (i) whether is closed in ; (ii) whether is dense in the closed subset of cut out by elements in which induce zero evaluation maps at all the places in . We also ask these questions considering only the algebraic Brauer group. We give answers to such questions for homogeneous spaces under semisimple simply connected groups with commutative stabilizers.
Keywords
Cite
@article{arxiv.2508.20652,
title = {Description of the strong approximation locus using Brauer-Manin obstruction for homogeneous spaces with commutative stabilizers},
author = {Victor de Vries and Haowen Zhang},
journal= {arXiv preprint arXiv:2508.20652},
year = {2025}
}
Comments
28 pages, comments welcome!