{ "id": "1509.03269", "version": "v1", "published": "2015-09-10T18:48:58.000Z", "updated": "2015-09-10T18:48:58.000Z", "title": "Categorical actions on unipotent representations I. Finite unitary groups", "authors": [ "Olivier Dudas", "Michela Varagnolo", "Eric Vasserot" ], "comment": "71 pages", "categories": [ "math.RT" ], "abstract": "Using Harish-Chandra induction and restriction, we construct a categorical action of a Kac-Moody algebra on the category of unipotent representations of finite unitary groups in non-defining characteristic. We show that the decategorified representation is naturally isomorphic to a direct sum of level 2 Fock spaces. From our construction we deduce that the Harish-Chandra branching graph coincide with the crystal graph of these Fock spaces, solving a recent conjecture of Gerber-Hiss-Jacon. We also obtain derived equivalences between blocks, yielding Brou\\'e's abelian defect groups conjecture for unipotent $\\ell$-blocks at linear primes $\\ell$.", "revisions": [ { "version": "v1", "updated": "2015-09-10T18:48:58.000Z" } ], "analyses": { "keywords": [ "finite unitary groups", "unipotent representations", "categorical action", "broues abelian defect groups conjecture", "fock spaces" ], "note": { "typesetting": "TeX", "pages": 71, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2015arXiv150903269D" } } }