Indices of 1-forms on an isolated complete intersection singularity
Indices of 1-forms on an isolated complete intersection singularity
复制标题
孤立完全交集奇点上 1-形式的指数
DOI:
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发表时间:
2001
期刊:
影响因子:
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通讯作者:
S. Gusein
中科院分区:
文献类型:
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作者:
W. Ebeling;S. Gusein
There are some generalizations of the classical Eisenbud-Levine-Khimshashvili formula for the index of a singular point of an analytic vector field on $R^n$ for vector fields on singular varieties. We offer an alternative approach based on the study of indices of 1-forms instead of vector fields. When the variety under consideration is a real isolated complete intersection singularity (icis), we define an index of a (real) 1-form on it. In the complex setting we define an index of a holomorphic 1-form on a complex icis and express it as the dimension of a certain algebra. In the real setting, for an icis $V=f^{-1}(0)$, $f:(C^n, 0) o (C^k, 0)$, $f$ is real, we define a complex analytic family of quadratic forms parameterized by the points $epsilon$ of the image $(C^k, 0)$ of the map $f$, which become real for real $epsilon$ and in this case their signatures defer from the "real" index by $chi(V_epsilon)-1$, where $chi(V_epsilon)$ is the Euler characteristic of the corresponding smoothing $V_epsilon=f^{-1}(epsilon)cap B_delta$ of the icis $V$.