English

Totally Ramified Maximal Tori and Bruhat-Tits theory

Representation Theory 2024-09-17 v2 Group Theory

Abstract

Suppose kk is a nonarchimedean local field, KK is a maximally unramified extension of kk, and G\mathbf{G} is a connected reductive kk-group. If T\mathbf{T} is a KK-minisotropic maximal kk-torus in G\mathbf{G}, then we use Bruhat-Tits theory to describe the stable classes in the G\mathbf{G}-orbit of T\mathbf{T}, the rational classes in the G\mathbf{G}-orbit of T\mathbf{T}, and the kk-embeddings, up to rational conjugacy, into G\mathbf{G} of T\mathbf{T}. We also provide, via Bruhat-Tits theory, a complete and explicit description of: the rational conjugacy classes of KK-minisotropic maximal tame kk-tori in G\mathbf{G}; the stable classes of KK-minisotropic maximal tame kk-tori in G\mathbf{G}; and the kk-embeddings, up to rational conjugacy, into G\mathbf{G} of a KK-minisotropic maximal tame kk-torus of G\mathbf{G}.

Keywords

Cite

@article{arxiv.2309.09049,
  title  = {Totally Ramified Maximal Tori and Bruhat-Tits theory},
  author = {Stephen DeBacker},
  journal= {arXiv preprint arXiv:2309.09049},
  year   = {2024}
}

Comments

Comments welcome! Appendices by Ram Ekstrom and Mitya Boyarchenko, Stephen DeBacker, Anna Spice, Loren Spice, and Cheng-Chiang Tsai. Version two includes some new results and corrections