{ "id": "2002.12864", "version": "v1", "published": "2020-02-28T17:00:22.000Z", "updated": "2020-02-28T17:00:22.000Z", "title": "$C^\\ast$-blocks and crossed products for classical $p$-adic groups", "authors": [ "Alexandre Afgoustidis", "Anne-Marie Aubert" ], "comment": "35 pages", "categories": [ "math.RT", "math.OA" ], "abstract": "Let $G$ be a real or $p$-adic reductive group. We consider the tempered dual of $G$, and its connected components. For real groups, Wassermann proved in 1987, by noncommutative-geometric methods, that each connected component has a simple geometric structure which encodes the reducibility of induced representations. For $p$-adic groups, each connected component of the tempered dual comes with a compact torus equipped with a finite group action, and we prove that a version of Wassermann's theorem holds true under a certain geometric assumption on the structure of stabilizers for that action. We then focus on the case where $G$ is a quasi-split symplectic, orthogonal or unitary group, and explicitly determine the connected components for which the geometric assumption is satisfied.", "revisions": [ { "version": "v1", "updated": "2020-02-28T17:00:22.000Z" } ], "analyses": { "subjects": [ "22E50", "22D25" ], "keywords": [ "adic groups", "connected component", "crossed products", "wassermanns theorem holds true", "geometric assumption" ], "note": { "typesetting": "TeX", "pages": 35, "language": "en", "license": "arXiv", "status": "editable" } } }