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Main Author: Namikawa, Yoshinori
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2408.03012
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author Namikawa, Yoshinori
author_facet Namikawa, Yoshinori
contents Let $(X, ω)$ be a conical symplectic variety of dimension $2n$ which has a projective symplectic resolution. Assume that $X$ admits an effective Hamiltonian action of an $n$-dimensional algebraic torus $T^n$, compatible with the conical $\mathbf{C}^*$-action. A typical example of $X$ is a toric hyperkahler variety $Y(A,0)$. In this article, we prove that this property characterizes $Y(A,0)$ with $A$ unimodular. More precisely, if $(X, ω)$ is such a conical symplectic variety, then there is a $T^n$-equivariant (complex analytic) isomorphism $φ: (X, ω) \to (Y(A,0), ω_{Y(A,0)})$ under which both moment maps are identified. Moreover $φ$ sends the center $0_X$ of $X$ to the center $0_{Y(A,0)}$ of $Y(A,0)$.
format Preprint
id arxiv_https___arxiv_org_abs_2408_03012
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Towards a characterization of toric hyperkähler varieties among symplectic singularities
Namikawa, Yoshinori
Algebraic Geometry
14, 32
Let $(X, ω)$ be a conical symplectic variety of dimension $2n$ which has a projective symplectic resolution. Assume that $X$ admits an effective Hamiltonian action of an $n$-dimensional algebraic torus $T^n$, compatible with the conical $\mathbf{C}^*$-action. A typical example of $X$ is a toric hyperkahler variety $Y(A,0)$. In this article, we prove that this property characterizes $Y(A,0)$ with $A$ unimodular. More precisely, if $(X, ω)$ is such a conical symplectic variety, then there is a $T^n$-equivariant (complex analytic) isomorphism $φ: (X, ω) \to (Y(A,0), ω_{Y(A,0)})$ under which both moment maps are identified. Moreover $φ$ sends the center $0_X$ of $X$ to the center $0_{Y(A,0)}$ of $Y(A,0)$.
title Towards a characterization of toric hyperkähler varieties among symplectic singularities
topic Algebraic Geometry
14, 32
url https://arxiv.org/abs/2408.03012