{ "id": "1005.1662", "version": "v6", "published": "2010-05-10T20:18:14.000Z", "updated": "2011-05-31T08:45:55.000Z", "title": "Some properties of Lubin-Tate cohomology for classifying spaces of finite groups", "authors": [ "Andrew Baker", "Birgit Richter" ], "comment": "Minor changes, section on Frobenius algebra structure removed. Final version: to appear in Central European Journal of Mathematics under title `Galois theory and Lubin-Tate cochains on classifying spaces'", "categories": [ "math.AT", "math.RA" ], "abstract": "We consider brave new cochain extensions $F(BG_+,R)\\to F(EG_+,R)$, where $R$ is either a Lubin-Tate spectrum $E_n$ or the related 2-periodic Morava K-theory $K_n$, and $G$ is a finite group. When $R$ is an Eilenberg-Mac Lane spectrum, in some good cases such an extension is a $G$-Galois extension in the sense of John Rognes, but not always faithful. We prove that for $E_n$ and $K_n$ these extensions are always faithful in the $K_n$ local category. However, for a cyclic $p$-group $C_{p^r}$, the cochain extension $F({BC_{p^r}}_+,E_n) \\to F({EC_{p^r}}_+,E_n)$ is not a Galois extensions because it ramifies. As a consequence, it follows that the $E_n$-theory Eilenberg-Moore spectral sequence for $G$ and $BG$ does not always converge to its expected target.", "revisions": [ { "version": "v6", "updated": "2011-05-31T08:45:55.000Z" } ], "analyses": { "subjects": [ "55P43", "13B05", "55N22", "55P60" ], "keywords": [ "finite group", "lubin-tate cohomology", "classifying spaces", "galois extension", "cochain extension" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2010arXiv1005.1662B" } } }