English

An Indicator Formula for the Hopf Algebra $k^{S_{n-1}}\#kC_n$

Rings and Algebras 2022-09-28 v3

Abstract

The semisimple bismash product Hopf algebra Jn=kSn1#kCnJ_n=k^{S_{n-1}}\#kC_n for an algebraically closed field kk is constructed using the matched pair actions of CnC_n and Sn1S_{n-1} on each other. In this work, we reinterpret these actions and use an understanding of the involutions of Sn1S_{n-1} to derive a new Froebnius-Schur indicator formula for irreps of JnJ_n and show that for nn odd, all indicators of JnJ_n are nonnegative. We also derive a variety of counting formulas including Theorem 6.2.2 which fully describes the indicators of all 22-dimensional irreps of JnJ_n and Theorem 6.1.2 which fully describes the indicators of all odd-dimensional irreps of JnJ_n and use these formulas to show that nonzero indicators become rare for large nn.

Keywords

Cite

@article{arxiv.2208.12714,
  title  = {An Indicator Formula for the Hopf Algebra $k^{S_{n-1}}\#kC_n$},
  author = {Kayla Orlinsky},
  journal= {arXiv preprint arXiv:2208.12714},
  year   = {2022}
}