Adjoint Jordan blocks for simple algebraic groups of type $C_{\ell}$ in characteristic two
Fuente:
arXiv
Enregistré dans:
| Auteur principal: | |
|---|---|
| Format: | Preprint |
| Publié: |
2023
|
| Sujets: | |
| Accès en ligne: | |
| Tags: |
Ajouter un tag
Pas de tags, Soyez le premier à ajouter un tag!
|
| _version_ | 1866916107553603584 |
|---|---|
| author | Korhonen, Mikko |
| author_facet | Korhonen, Mikko |
| contents | Let $G$ be a simple algebraic group over an algebraically closed field $K$ with Lie algebra $\mathfrak{g}$. For unipotent elements $u \in G$ and nilpotent elements $e \in \mathfrak{g}$, the Jordan block sizes of $\operatorname{Ad}(u)$ and $\operatorname{ad}(e)$ are known in most cases. In the cases that remain, the group $G$ is of classical type in bad characteristic, so $\operatorname{char} K = 2$ and $G$ is of type $B_{\ell}$, $C_{\ell}$, or $D_{\ell}$.
In this paper, we consider the case where $G$ is of type $C_{\ell}$ and $\operatorname{char} K = 2$. As our main result, we determine the Jordan block sizes of $\operatorname{Ad}(u)$ and $\operatorname{ad}(e)$ for all unipotent $u \in G$ and nilpotent $e \in \mathfrak{g}$. In the case where $G$ is of adjoint type, we will also describe the Jordan block sizes on $[\mathfrak{g}, \mathfrak{g}]$. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2303_14902 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Adjoint Jordan blocks for simple algebraic groups of type $C_{\ell}$ in characteristic two Korhonen, Mikko Group Theory Representation Theory 17B45, 20G99 Let $G$ be a simple algebraic group over an algebraically closed field $K$ with Lie algebra $\mathfrak{g}$. For unipotent elements $u \in G$ and nilpotent elements $e \in \mathfrak{g}$, the Jordan block sizes of $\operatorname{Ad}(u)$ and $\operatorname{ad}(e)$ are known in most cases. In the cases that remain, the group $G$ is of classical type in bad characteristic, so $\operatorname{char} K = 2$ and $G$ is of type $B_{\ell}$, $C_{\ell}$, or $D_{\ell}$. In this paper, we consider the case where $G$ is of type $C_{\ell}$ and $\operatorname{char} K = 2$. As our main result, we determine the Jordan block sizes of $\operatorname{Ad}(u)$ and $\operatorname{ad}(e)$ for all unipotent $u \in G$ and nilpotent $e \in \mathfrak{g}$. In the case where $G$ is of adjoint type, we will also describe the Jordan block sizes on $[\mathfrak{g}, \mathfrak{g}]$. |
| title | Adjoint Jordan blocks for simple algebraic groups of type $C_{\ell}$ in characteristic two |
| topic | Group Theory Representation Theory 17B45, 20G99 |
| url | https://arxiv.org/abs/2303.14902 |