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arXiv 2008.08829math.DGmath.AG
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基除子与平衡度量

Basis divisors and balanced metrics

Yanir A. Rubinstein, Gang Tian, Kewei Zhang

AI总结:

本文为Fujita-Odaka代数不变量$δ_m$提供了解析解释,证明其为Bergman空间上量化Ding泛函的强制阈值并刻画平衡度量存在性,同时推广至Kähler-Ricci孤立子及逼近结果。

摘要:

利用对数典范阈值和基除子,Fujita--Odaka引入了纯代数几何不变量$δ_m$,其在$m$中的极限现已知可刻画Fano簇上的一致K-稳定性。正如Blum-Jonsson所示,这可推广至一般极化,结合Berman、Boucksom和Jonsson的工作,现已知这些$δ_m$-不变量的极限可刻画一致Ding稳定性。自Fujita-Odaka的工作以来,一个基本问题是为这些不变量寻找解析解释。我们证明每个$δ_m$是第$m$个Bergman空间上量化Ding泛函的强制阈值,从而刻画了平衡度量的存在性。该方法有诸多应用。最基本的是提供了一种计算这些不变量的替代方法,这对$\mathbb{P}^n$而言也是全新的。其次,它允许我们引入代数定义的不变量,以刻画Kähler-Ricci孤立子(及更一般的Berman-Witt Nyström的$g$-孤立子)及其耦合版本的存在性。第三,它导出了在有自同构存在时涉及平衡度量的逼近结果,推广了Donaldson的某些结论。

英文摘要:

Using log canonical thresholds and basis divisors Fujita--Odaka introduced purely algebro-geometric invariants $δ_m$ whose limit in $m$ is now known to characterize uniform K-stability on a Fano variety. As shown by Blum-Jonsson this carries over to a general polarization, and together with work of Berman, Boucksom, and Jonsson, it is now known that the limit of these $δ_m$-invariants characterizes uniform Ding stability. A basic question since Fujita-Odaka's work has been to find an analytic interpretation of these invariants. We show that each $δ_m$ is the coercivity threshold of a quantized Ding functional on the $m$-th Bergman space and thus characterizes the existence of balanced metrics. This approach has a number of applications. The most basic one is that it provides an alternative way to compute these invariants, which is new even for $\mathbb{P}^n$. Second, it allows us to introduce algebraically defined invariants that characterize the existence of Kähler-Ricci solitons (and the more general $g$-solitons of Berman-Witt Nyström), as well as coupled versions thereof. Third, it leads to approximation results involving balanced metrics in the presence of automorphisms that extend some results of Donaldson.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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