{ "id": "1703.02187", "version": "v1", "published": "2017-03-07T02:49:55.000Z", "updated": "2017-03-07T02:49:55.000Z", "title": "Degree and the Brauer-Manin obstruction", "authors": [ "Brendan Creutz", "Bianca Viray" ], "comment": "22 pages", "categories": [ "math.NT", "math.AG" ], "abstract": "Let X be a smooth variety over a number field k embedded as a degree d subvariety of $\\mathbb{P}^n$ and suppose that X is a counterexample to the Hasse principle explained by the Brauer-Manin obstruction. We consider the question of whether the obstruction is given by the d-primary subgroup of the Brauer group, which would have both theoretic and algorithmic implications. We prove that this question has a positive answer in the case of torsors under abelian varieties, Kummer varieties and (conditional on finiteness of Tate-Shafarevich groups) bielliptic surfaces. In the case of Kummer varieties we show, more specifically, that the obstruction is already given by the 2-primary torsion. We construct a conic bundle over an elliptic curve that shows that, in general, the answer is no.", "revisions": [ { "version": "v1", "updated": "2017-03-07T02:49:55.000Z" } ], "analyses": { "subjects": [ "14G05", "11G35", "14F22" ], "keywords": [ "brauer-manin obstruction", "kummer varieties", "algorithmic implications", "conic bundle", "number field" ], "note": { "typesetting": "TeX", "pages": 22, "language": "en", "license": "arXiv", "status": "editable" } } }