{ "id": "2410.06217", "version": "v2", "published": "2024-10-08T17:24:22.000Z", "updated": "2024-12-03T01:06:14.000Z", "title": "On Brauer groups of tame stacks", "authors": [ "Niven Achenjang" ], "comment": "57 pages, including ~11 pages of examples at the end. Comments are very welcome! v2: added some new results about Brauer groups of proper stacky curves (Section 7.2)", "categories": [ "math.AG", "math.NT" ], "abstract": "We develop some general tools for computing the Brauer group of a tame algebraic stack $\\mathscr X$ by studying the difference between it and the Brauer group of the coarse space $X$ of $\\mathscr X$. It is our hope that these tools will be used to simplify future computations of Brauer groups of stacks. Informally, we show that $\\operatorname{Br}\\mathscr X$ is often built from $\\operatorname{Br} X$ and \"information about the Picard groups of the fibers of $\\mathscr X\\to X$''. Along these lines, we compute, for example, the Brauer group of the moduli stack $\\mathscr Y(1)_S$ of elliptic curves, over any regular noetherian $\\mathbb Z[1/2]$-scheme $S$ as well as the Brauer groups of (many) stacky curves (allowing generic stabilizers) over algebraically closed fields.", "revisions": [ { "version": "v2", "updated": "2024-12-03T01:06:14.000Z" } ], "analyses": { "subjects": [ "14F22", "14D23", "14A20" ], "keywords": [ "brauer group", "tame stacks", "tame algebraic stack", "coarse space", "general tools" ], "note": { "typesetting": "TeX", "pages": 57, "language": "en", "license": "arXiv", "status": "editable" } } }