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Main Authors: Chung, Kiryong, Kim, Jaehyun, Kim, Jeong-Seop
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2412.17721
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author Chung, Kiryong
Kim, Jaehyun
Kim, Jeong-Seop
author_facet Chung, Kiryong
Kim, Jaehyun
Kim, Jeong-Seop
contents Let $X$ be the Fano threefold of index one, degree $22$, and $\mathrm{Pic}(X)\cong\mathbb{Z}$. Such a threefold $X$ can be realized by a regular zero section $\mathbf{s}$ of $(\bigwedge^2\mathcal{F}^{*})^{\oplus 3}$ over Grassmannian variety $\mathrm{Gr}(3,V)$, $\dim V=7$ with the universal subbundle $\mathcal{F}$. When the section $\mathbf{s}$ is given by the net of the $\mathrm{SL}_2$-invariant skew forms, we call it by the Mukai-Umemura (MU) variety. In this paper, we prove that the Hilbert scheme of rational quartic curves in the MU-variety is smooth and compute its Poincaré polynomial by applying the Białynicki-Birula's theorem.
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institution arXiv
publishDate 2024
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spellingShingle Rational quartic curves in the Mukai-Umemura variety
Chung, Kiryong
Kim, Jaehyun
Kim, Jeong-Seop
Algebraic Geometry
Let $X$ be the Fano threefold of index one, degree $22$, and $\mathrm{Pic}(X)\cong\mathbb{Z}$. Such a threefold $X$ can be realized by a regular zero section $\mathbf{s}$ of $(\bigwedge^2\mathcal{F}^{*})^{\oplus 3}$ over Grassmannian variety $\mathrm{Gr}(3,V)$, $\dim V=7$ with the universal subbundle $\mathcal{F}$. When the section $\mathbf{s}$ is given by the net of the $\mathrm{SL}_2$-invariant skew forms, we call it by the Mukai-Umemura (MU) variety. In this paper, we prove that the Hilbert scheme of rational quartic curves in the MU-variety is smooth and compute its Poincaré polynomial by applying the Białynicki-Birula's theorem.
title Rational quartic curves in the Mukai-Umemura variety
topic Algebraic Geometry
url https://arxiv.org/abs/2412.17721