English

Modular representations of $\mathrm{GL}_2({\mathbb F}_q)$ using calculus

Representation Theory 2024-11-27 v2 Number Theory

Abstract

We show that certain modular induced representations of GL2(Fq)\mathrm{GL}_2({\mathbb F}_q) can be written as cokernels of operators acting on symmetric power representations of GL2(Fq)\mathrm{GL}_2({\mathbb F}_q). When the induction is from the Borel subgroup, respectively the anisotropic torus, the operators involve multiplication by newly defined twisted Dickson polynomials, respectively, twisted Serre operators. Our isomorphisms are explicitly defined using differential operators. As a corollary, we improve some periodicity results for quotients in the theta filtration.

Keywords

Cite

@article{arxiv.2308.10246,
  title  = {Modular representations of $\mathrm{GL}_2({\mathbb F}_q)$ using calculus},
  author = {Eknath Ghate and Arindam Jana},
  journal= {arXiv preprint arXiv:2308.10246},
  year   = {2024}
}

Comments

To appear in Forum Mathematicum

R2 v1 2026-06-28T11:59:44.535Z