English

Projective smooth representations in natural characteristic

Number Theory 2024-11-21 v1 Representation Theory

Abstract

We investigate under which circumstances there exists nonzero {\it{projective}} smooth \field[G]\field[G]-modules, where \field\field is a field of characteristic pp and GG is a locally pro-pp group. We prove the non-existence of (non-trivial) projective objects for so-called {\it{fair}} groups -- a family including G(F)\bf{G}(\frak{F}) for a connected reductive group G\bf{G} defined over a non-archimedean local field F\frak{F}. This was proved in \cite{SS24} for finite extensions F/Qp\frak{F}/\Bbb{Q}_p. The argument we present in this note has the benefit of being completely elementary and, perhaps more importantly, adaptable to F=Fq( ⁣(t) ⁣)\frak{F}=\Bbb{F}_q(\!(t)\!). Finally, we elucidate the fairness condition via a criterion in the Chabauty space of GG.

Keywords

Cite

@article{arxiv.2411.12867,
  title  = {Projective smooth representations in natural characteristic},
  author = {Amit Ophir and Claus Sorensen},
  journal= {arXiv preprint arXiv:2411.12867},
  year   = {2024}
}

Comments

12 pages

R2 v1 2026-06-28T20:05:36.041Z