On Picard groups of blocks of finite groups

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 a complete discrete valuation ring O of characteristic zero with an algebraic closure k of F-p as residue field is a colimit of finite Picard groups of blocks over p-adic subrings of 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. (C) 2019 Elsevier Inc. All rights reserved.