{ "id": "1805.08902", "version": "v1", "published": "2018-05-22T23:11:14.000Z", "updated": "2018-05-22T23:11:14.000Z", "title": "On Picard groups of blocks of finite groups", "authors": [ "Robert Boltje", "Radha Kessar", "Markus Linckelmann" ], "categories": [ "math.RT", "math.GR" ], "abstract": "We show that the subgroup of the Picard group of a $p$-block of a finite group given by bimodules with endopermutation sources modulo the automorphism group of a source algebra is determined locally in terms of the fusion system on a defect group. We show that the Picard group of a block over the a complete discrete valuation ring ${\\mathcal O}$ of characteristic zero with an algebraic closure $k$ of ${\\mathbb F}_p$ as residue field is a colimit of finite Picard groups of blocks over $p$-adic subrings of ${\\mathcal O}$. We apply the results to blocks with an abelian defect group and Frobenius inertial quotient, and specialise this further to blocks with cyclic or Klein four defect groups.", "revisions": [ { "version": "v1", "updated": "2018-05-22T23:11:14.000Z" } ], "analyses": { "subjects": [ "20C20", "20C11" ], "keywords": [ "finite group", "abelian defect group", "finite picard groups", "frobenius inertial quotient", "endopermutation sources modulo" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }