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arXiv 1709.04604math.DG
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半黎曼弯曲积上的Ricci几乎孤子

Ricci Almost Solitons on semi-Riemannian Warped Products

Keti Tenenblat, Valter Borges

摘要:

在考虑势函数是否依赖于光纤的情况下,刻画了半黎曼弯曲积上的Ricci几乎孤子。我们证明了纤维必然是爱因斯坦流形。作为我们的表征的结果,我们证明,当势函数取决于纤维,如果弯曲函数的梯度不采取行动的翻译,然后基地和翘曲产品也爱因斯坦流形。此外,我们证明了共形向量场在基底、纤维和翘曲积上的存在性。假设翘曲产品的完整性,我们提供了一个分类这样的流形。当势函数依赖于纤维且翘曲函数的梯度为非正常向量场时,我们证明了基底是Brinkmann空间,纤维是Ricci平坦的.利用这一刻画,我们还证明了完备Ricci孤子的势函数只依赖于基。

英文摘要:

We characterize Ricci almost solitons on semi-Riemannian warped products, considering the potential function to depend on the fiber or not. We show that the fiber is necessarily an Einstein manifold. As a consequence of our characterization we prove that when the potential function depends on the fiber, if the gradient of the warping function does not act by translations then the base and the warped product are also Einstein manifolds. Moreover, we show the existence of conformal vector fields on the base, the fiber and on the warped product. Assuming completeness of the warped product we provide a classification of such manifolds. When the potential function depends on the fiber and the gradient of the warping functions is an improper vector field, we show that the base is a Brinkmann space and the fiber is Ricci flat. We use the characterization also to prove that the potential function of a complete Ricci soliton depends only on the base.

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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