English

Lifting polynomial representations of $\mathrm{SL}_2(p^r)$ from $\mathbb{F}_p$ to $\mathbb{Z}/p^s\mathbb{Z}$

Representation Theory 2025-11-24 v2 Group Theory

Abstract

We describe all of the irreducible polynomial FpSL2(pr)\mathbb{F}_p\mathrm{SL}_2(p^r) representations which lift to (Z/psZ)SL2(pr)(\mathbb{Z}/p^s\mathbb{Z})\mathrm{SL}_2(p^r) representations for s>1s>1, observing that they almost never do. We also show that two related indecomposable FpSL2(pr)\mathbb{F}_p \mathrm{SL}_2(p^r) representations cannot be lifted to Z/psZ\mathbb{Z}/p^s\mathbb{Z} representations for s>1s>1.

Keywords

Cite

@article{arxiv.2411.16379,
  title  = {Lifting polynomial representations of $\mathrm{SL}_2(p^r)$ from $\mathbb{F}_p$ to $\mathbb{Z}/p^s\mathbb{Z}$},
  author = {Chris Parker and Martin van Beek},
  journal= {arXiv preprint arXiv:2411.16379},
  year   = {2025}
}