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arXiv math/0603018math.DG
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具有可逆Dirac算子的度量空间

On the space of metrics with invertible Dirac operator

Mattias Dahl

摘要:

在紧自旋流形上,我们研究了狄拉克算子可逆的黎曼度量空间。第一个主要的结果是手术定理,指出这样的度量可以扩展到余维至少为三的手术的痕迹。然后证明了如果非空的度量空间可逆狄拉克运营商是断开的维数$n \equiv 0,1,3,7 \mod 8$,$n \geq 5$。作为一个推论如下结果存在的度量与谐波旋希钦和巴尔。最后,我们使用计算的eta不变的Botvinnik和Gilkey找到度量与谐波旋量的单连通流形上的循环群的行动。特别地,这适用于所有尺寸的球体$n \geq 5$。

英文摘要:

On a compact spin manifold we study the space of Riemannian metrics for which the Dirac operator is invertible. The first main result is a surgery theorem stating that such a metric can be extended over the trace of a surgery of codimension at least three. We then prove that if non-empty the space of metrics with invertible Dirac operators is disconnected in dimensions $n \equiv 0,1,3,7 \mod 8$, $n \geq 5$. As a corollary follows results on the existence of metrics with harmonic spinors by Hitchin and Bär. Finally we use computations of the eta invariant by Botvinnik and Gilkey to find metrics with harmonic spinors on simply connected manifolds with a cyclic group action. In particular this applies to spheres of all dimensions $n \geq 5$.

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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