{ "id": "0711.3023", "version": "v2", "published": "2007-11-19T21:47:31.000Z", "updated": "2008-08-04T13:56:17.000Z", "title": "Stacky Abelianization of an Algebraic Group", "authors": [ "Masoud Kamgarpour" ], "comment": "22 Pages", "categories": [ "math.AG" ], "abstract": "Let G be a connected algebraic group and let [G,G] be its commutator subgroup. We prove a conjecture of Drinfeld about the existence of a connected etale group cover H of [G,G], characterized by the following properties: every central extension of G, by a finite etale group scheme, splits over H, and the commutator map of G lifts to H. We prove, moreover, that the quotient stack of G by the natural action of H is the universal Deligne-Mumford Picard stack to which G maps.", "revisions": [ { "version": "v2", "updated": "2008-08-04T13:56:17.000Z" } ], "analyses": { "keywords": [ "algebraic group", "stacky abelianization", "universal deligne-mumford picard stack", "finite etale group scheme", "connected etale group cover" ], "note": { "typesetting": "TeX", "pages": 22, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2007arXiv0711.3023K" } } }