English

Block theory and Brauer's first main theorem for profinite groups

Representation Theory 2021-10-11 v3

Abstract

We develop the local-global theory of blocks for profinite groups. Given a field kk of characteristic pp and a profinite group GG, one may express the completed group algebra k[[G]]k[[G]] as a product iIBi\prod_{i\in I}B_i of closed indecomposable algebras, called the blocks of GG. To each block BB of GG we associate a pro-pp subgroup of GG, called the defect group of BB, unique up to conjugacy in GG. We give several characterizations of the defect group in analogy with defect groups of blocks of finite groups. Our main theorem is a Brauer correspondence between the blocks of GG with defect group DD and the blocks of the normalizer NG(D)N_G(D) with defect group DD.

Keywords

Cite

@article{arxiv.2105.10964,
  title  = {Block theory and Brauer's first main theorem for profinite groups},
  author = {Ricardo J. Franquiz Flores and John W. MacQuarrie},
  journal= {arXiv preprint arXiv:2105.10964},
  year   = {2021}
}

Comments

25 pages. Final version, to be published in Advances in Mathematics

R2 v1 2026-06-24T02:23:11.982Z