Saved in:
| Main Author: | |
|---|---|
| Format: | Preprint |
| Published: |
2024
|
| Subjects: | |
| Online Access: | https://arxiv.org/abs/2412.20809 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1866915084914130944 |
|---|---|
| author | Panyushev, Dmitri I. |
| author_facet | Panyushev, Dmitri I. |
| contents | Let $G$ be a simple algebraic group and $\mathcal O$ a nilpotent orbit in $\mathfrak g$. Let ${\mathbf{CS}}(\mathcal O)$ denote the affine cone over the secant variety of $\overline{\mathbb P\mathcal O}\subset \mathbb P\mathfrak g$. Using the theory of doubled actions of $G$, we describe ${\mathbf{CS}}(\mathcal O)$ for all $\mathcal O$. We compute $\dim{\mathbf{CS}}(\mathcal O)$ using the complexity and rank of the $G$-variety $\mathcal O$ and show that there is an abelian subalgebra $\mathfrak t_{\mathcal O}\subset\mathfrak g$ such that ${\mathbf{CS}}(\mathcal O)$ is the closure of $G{\cdot}\mathfrak t_\mathcal O$. Another observation is that ${\mathbf{CS}}(\mathcal O)$ coincide with the closure of the image of the moment map associated with the cotangent bundle of $\mathcal O$. We also compute the complexity and rank for all nilpotent orbits. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2412_20809 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Nilpotent orbits and their secant varieties Panyushev, Dmitri I. Algebraic Geometry Representation Theory Let $G$ be a simple algebraic group and $\mathcal O$ a nilpotent orbit in $\mathfrak g$. Let ${\mathbf{CS}}(\mathcal O)$ denote the affine cone over the secant variety of $\overline{\mathbb P\mathcal O}\subset \mathbb P\mathfrak g$. Using the theory of doubled actions of $G$, we describe ${\mathbf{CS}}(\mathcal O)$ for all $\mathcal O$. We compute $\dim{\mathbf{CS}}(\mathcal O)$ using the complexity and rank of the $G$-variety $\mathcal O$ and show that there is an abelian subalgebra $\mathfrak t_{\mathcal O}\subset\mathfrak g$ such that ${\mathbf{CS}}(\mathcal O)$ is the closure of $G{\cdot}\mathfrak t_\mathcal O$. Another observation is that ${\mathbf{CS}}(\mathcal O)$ coincide with the closure of the image of the moment map associated with the cotangent bundle of $\mathcal O$. We also compute the complexity and rank for all nilpotent orbits. |
| title | Nilpotent orbits and their secant varieties |
| topic | Algebraic Geometry Representation Theory |
| url | https://arxiv.org/abs/2412.20809 |