English

Conjectural invariance with respect to the fusion system of an almost-source algebra

Representation Theory 2021-03-04 v1

Abstract

We show that, given an almost-source algebra AA of a pp-block of a finite group GG, then the unit group of AA contains a basis stabilized by the left and right multiplicative action of the defect group if and only if, in a sense to be made precise, certain relative multiplicities of local pointed groups are invariant with respect to the fusion system. We also show that, when GG is pp-solvable, those two equivalent conditions hold for some almost-source algebra of the given pp-block. One motive lies in the fact that, by a theorem of Linckelmann, if the two equivalent conditions hold for AA, then any stable basis for AA is semicharacteristic for the fusion system.

Keywords

Cite

@article{arxiv.2103.02426,
  title  = {Conjectural invariance with respect to the fusion system of an almost-source algebra},
  author = {Laurence Barker and Matthew Gelvin},
  journal= {arXiv preprint arXiv:2103.02426},
  year   = {2021}
}