{ "id": "1412.7685", "version": "v1", "published": "2014-12-24T15:21:54.000Z", "updated": "2014-12-24T15:21:54.000Z", "title": "Cohomology of absolute Galois groups", "authors": [ "Claudio Quadrelli" ], "comment": "Ph.D. thesis at Western University (Canada) and Universit\\`a di Milano-Bicocca (Italy), 103 pages, 1 figure", "categories": [ "math.GR", "math.NT" ], "abstract": "The main problem this thesis deals with is the characterization of profinite groups which are realizable as absolute Galois groups of fields: this is currently one of the major problems in Galois theory. Usually one reduces the problem to the pro-$p$ case, i.e., one would like to know which pro-$p$ groups occur as maximal pro-$p$ Galois groups, i.e., maximal pro-$p$ quotients of absolute Galois groups. Indeed, pro-$p$ groups are easier to deal with than general profinite groups, yet they carry a lot of information on the whole absolute Galois group. We define a new class of pro-$p$ groups, called Bloch-Kato pro-$p$ group, whose Galois cohomology satisfies the consequences of the Bloch-Kato conjecture. Also we introduce the notion of cyclotomic orientation for a pro-$p$ group. With this approach, we are able to recover new substantial information about the structure of maximal pro-$p$ Galois groups, and in particular on $\\theta$-abelian pro-$p$ groups, which represent the \"upper bound\" of such groups. Also, we study the restricted Lie algebra and the universal envelope induced by the Zassenhaus filtration of a maximal pro-$p$ Galois group, and their relations with Galois cohomology via Koszul duality. Altogether, this thesis provides a rather new approach to maximal pro-$p$ Galois groups, besides new substantial results.", "revisions": [ { "version": "v1", "updated": "2014-12-24T15:21:54.000Z" } ], "analyses": { "subjects": [ "12G05", "20J06", "20E18", "12F10" ], "keywords": [ "absolute galois group", "general profinite groups", "galois cohomology satisfies", "bloch-kato conjecture", "substantial results" ], "tags": [ "dissertation" ], "note": { "typesetting": "TeX", "pages": 103, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2014arXiv1412.7685Q" } } }