English

Isotypic blocks of finite groups algebras that are not $p$-permutation equivalent

Representation Theory 2025-06-05 v1 Group Theory

Abstract

We show that Kessar's isotypy between Galois conjugate blocks of finite group algebras does not always lift to a pp-permutation equivalence. We also provide examples of Galois conjugate blocks which are isotypic but not pp-permutation equivalent. These results help to clarify the distinction between a pp-permutation equivalence and an isotypy, and may be useful in determining necessary and sufficient conditions for when an isotypy lifts to a pp-permutation equivalence.

Keywords

Cite

@article{arxiv.2506.03446,
  title  = {Isotypic blocks of finite groups algebras that are not $p$-permutation equivalent},
  author = {John Revere McHugh},
  journal= {arXiv preprint arXiv:2506.03446},
  year   = {2025}
}