{ "id": "1210.1564", "version": "v3", "published": "2012-10-04T19:57:56.000Z", "updated": "2013-08-06T12:06:46.000Z", "title": "Group cohomology and control of p-fusion", "authors": [ "David Benson", "Jesper Grodal", "Ellen Henke" ], "comment": "15 pages; v3: title and exposition shortened, and a short section on Lannes' T-functor removed, following comments by referees. Final version, to appear in Invent. Math", "doi": "10.1007/s00222-013-0489-5", "categories": [ "math.AT", "math.GR" ], "abstract": "We show that if an inclusion of finite groups H < G of index prime to p induces a homeomorphism of mod p cohomology varieties, or equivalently an F-isomorphism in mod p cohomology, then H controls p-fusion in G, if p is odd. This generalizes classical results of Quillen who proved this when H is a Sylow p-subgroup, and furthermore implies a hitherto difficult result of Mislin about cohomology isomorphisms. For p=2 we give analogous results, at the cost of replacing mod p cohomology with higher chromatic cohomology theories. The results are consequences of a general algebraic theorem we prove, that says that isomorphisms between p-fusion systems over the same finite p-group are detected on elementary abelian p-groups if p odd and abelian 2-groups of exponent at most 4 if p=2.", "revisions": [ { "version": "v3", "updated": "2013-08-06T12:06:46.000Z" } ], "analyses": { "subjects": [ "20J06", "20D20", "20J05", "55P60" ], "keywords": [ "group cohomology", "higher chromatic cohomology theories", "elementary abelian p-groups", "general algebraic theorem", "cohomology varieties" ], "tags": [ "journal article" ], "note": { "typesetting": "TeX", "pages": 15, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2012arXiv1210.1564B" } } }