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arXiv math/0510150math.DG
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允许点态对称的仿射超曲面

Affine hypersurfaces admitting a pointwise symmetry

Ying Lu, Christine Scharlach

摘要:

一个仿射超曲面被称为允许点态对称,如果存在切空间的自同构群的子群,它保持(点态)仿射度量h,差张量K和仿射形状算子S。本文研究了三维正定仿射超曲面。首先我们解决一个代数问题。我们确定了欧氏向量空间(V,h)上SO(3)作用下的对(K,S)的非平凡稳定子G,并找到了每个(SO(3)/G)-轨道的代表(K和S的标准型).然后,我们对所有非平凡稳定子G(除Z_2外)具有点态G-对称性的超曲面进行了分类。除了众所周知的超曲面,我们还得到了二维仿射球面的翘曲积结构(分别是)。二次曲面)和曲线。

英文摘要:

An affine hypersurface is said to admit a pointwise symmetry, if there exists a subgroup of the automorphism group of the tangent space, which preserves (pointwise) the affine metric h, the difference tensor K and the affine shape operator S. In this paper, we deal with positive definite affine hypersurfaces of dimension three. First we solve an algebraic problem. We determine the non-trivial stabilizers G of the pair (K,S) under the action of SO(3) on an Euclidean vectorspace (V,h) and find a representative (canonical form of K and S) of each (SO(3)/G)-orbit. Then, we classify hypersurfaces admitting a pointwise G-symmetry for all non-trivial stabilizers G (apart of Z_2). Besides well-known hypersurfaces we obtain e.g. warped product structures of two-dimensional affine spheres (resp. quadrics) and curves.

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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