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| Main Authors: | , |
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| Format: | Preprint |
| Published: |
2016
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/1603.06636 |
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| _version_ | 1866914870621896704 |
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| author | Fresse, Lucas Nishiyama, Kyo |
| author_facet | Fresse, Lucas Nishiyama, Kyo |
| contents | Given a decomposition of a vector space $V=V_1\oplus V_2$, the direct product $\mathfrak{X}$ of the projective space $\mathbb{P}(V_1)$ with a Grassmann variety $\mathrm{Gr}_k(V)$ can be viewed as a double flag variety for the symmetric pair $(G,K)=(\mathrm{GL}(V),\mathrm{GL}(V_1)\times\mathrm{GL}(V_2))$. Relying on the conormal variety for the action of $K$ on $\mathfrak{X}$, we show a geometric correspondence between the $K$-orbits of $\mathfrak{X}$ and the $K$-orbits of some appropriate exotic nilpotent cone. We also give a combinatorial interpretation of this correspondence in some special cases. Our construction is inspired by a classical result of Steinberg and by the recent work of Henderson and Trapa for the symmetric pair $(\mathrm{GL}(V),\mathrm{Sp}(V))$. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_1603_06636 |
| institution | arXiv |
| publishDate | 2016 |
| record_format | arxiv |
| spellingShingle | On the exotic Grassmannian and its nilpotent variety Fresse, Lucas Nishiyama, Kyo Representation Theory Given a decomposition of a vector space $V=V_1\oplus V_2$, the direct product $\mathfrak{X}$ of the projective space $\mathbb{P}(V_1)$ with a Grassmann variety $\mathrm{Gr}_k(V)$ can be viewed as a double flag variety for the symmetric pair $(G,K)=(\mathrm{GL}(V),\mathrm{GL}(V_1)\times\mathrm{GL}(V_2))$. Relying on the conormal variety for the action of $K$ on $\mathfrak{X}$, we show a geometric correspondence between the $K$-orbits of $\mathfrak{X}$ and the $K$-orbits of some appropriate exotic nilpotent cone. We also give a combinatorial interpretation of this correspondence in some special cases. Our construction is inspired by a classical result of Steinberg and by the recent work of Henderson and Trapa for the symmetric pair $(\mathrm{GL}(V),\mathrm{Sp}(V))$. |
| title | On the exotic Grassmannian and its nilpotent variety |
| topic | Representation Theory |
| url | https://arxiv.org/abs/1603.06636 |