{ "id": "1503.06504", "version": "v1", "published": "2015-03-23T01:29:41.000Z", "updated": "2015-03-23T01:29:41.000Z", "title": "Coassembly and the $K$-theory of finite groups", "authors": [ "Cary Malkiewich" ], "comment": "49 pages", "categories": [ "math.AT", "math.KT" ], "abstract": "We study the $K$-theory and Swan theory of the group ring $R[G]$, when $G$ is a finite group and $R$ is any discrete ring or ring spectrum. In this setting, the well-known assembly map for $K(R[G])$ has a lesser-known companion called the coassembly map. We prove that their composite is the equivariant norm of $K(R)$. As a result, we get a splitting of both assembly and coassembly after $K(n)$-localization, and an apparently new map from the Whitehead torsion group of $G$ over $R$ to the Tate cohomology of $BG$ with coefficients in $K(R)$.", "revisions": [ { "version": "v1", "updated": "2015-03-23T01:29:41.000Z" } ], "analyses": { "subjects": [ "18F25", "19D10", "55R12", "55R70" ], "keywords": [ "finite group", "whitehead torsion group", "tate cohomology", "equivariant norm", "swan theory" ], "note": { "typesetting": "TeX", "pages": 49, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2015arXiv150306504M" } } }