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arXiv 1005.1491gr-qc
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2+2弯曲时空的一个内禀刻画

An intrinsic characterization of 2+2 warped spacetimes

Joan Josep Ferrando, Juan Antonio Sáez

摘要:

我们给出了几个刻画2+2弯曲时空的等价条件:根据与弯曲乘积的2-平面相关联的投影子$v$(或规范2-形式$U$),在互补代数限制下存在Killing-Yano张量$A$。这些平面是Weyl和/或Ricci张量的主平面,并且可以从它们明确地获得。因此,我们得到了度量张量是2+2翘曲积的充要(局部)条件。这些条件只涉及黎曼张量的显式伴随。我们对共形2+2乘积时空作了类似的分析,并给出了它们的不变分类。变形积对应于这些不变类中的两个。更退化的类是一组产品的度量,也研究了从不变的角度来看。

英文摘要:

We give several equivalent conditions that characterize the 2+2 warped spacetimes: imposing the existence of a Killing-Yano tensor $A$ subject to complementary algebraic restrictions; in terms of the projector $v$ (or of the canonical 2-form $U$) associated with the 2-planes of the warped product. These planes are principal planes of the Weyl and/or Ricci tensors and can be explicitly obtained from them. Therefore, we obtain the necessary and sufficient (local) conditions for a metric tensor to be a 2+2 warped product. These conditions exclusively involve explicit concomitants of the Riemann tensor. We present a similar analysis for the conformally 2+2 product spacetimes and give an invariant classification of them. The warped products correspond to two of these invariant classes. The more degenerate class is the set of product metrics which are also studied from an invariant point of view.

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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