• Title/Summary/Keyword: spherically symmetric metric

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ON THE GEOMETRY OF VECTOR BUNDLES WITH FLAT CONNECTIONS

  • Abbassi, Mohamed Tahar Kadaoui;Lakrini, Ibrahim
    • Bulletin of the Korean Mathematical Society
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    • v.56 no.5
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    • pp.1219-1233
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    • 2019
  • Let $E{\rightarrow}M$ be an arbitrary vector bundle of rank k over a Riemannian manifold M equipped with a fiber metric and a compatible connection $D^E$. R. Albuquerque constructed a general class of (two-weights) spherically symmetric metrics on E. In this paper, we give a characterization of locally symmetric spherically symmetric metrics on E in the case when $D^E$ is flat. We study also the Einstein property on E proving, among other results, that if $k{\geq}2$ and the base manifold is Einstein with positive constant scalar curvature, then there is a 1-parameter family of Einstein spherically symmetric metrics on E, which are not Ricci-flat.

ON A CLASS OF LOCALLY PROJECTIVELY FLAT GENERAL (α, β)-METRICS

  • Mo, Xiaohuan;Zhu, Hongmei
    • Bulletin of the Korean Mathematical Society
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    • v.54 no.4
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    • pp.1293-1307
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    • 2017
  • General (${\alpha},{\beta}$)-metrics form a rich class of Finsler metrics. They include many important Finsler metrics, such as Randers metrics, square metrics and spherically symmetric metrics. In this paper, we find equations which are necessary and sufficient conditions for such Finsler metric to be locally projectively flat. By solving these equations, we obtain all of locally projectively flat general (${\alpha},{\beta}$)-metrics under certain condition. Finally, we manufacture explicitly new locally projectively flat Finsler metrics.