• Title/Summary/Keyword: conformally flatness

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REMARKS ON CONFORMAL TRANSFORMATION ON RIEMANNIAN MANIFOLDS

  • Kim, Byung-Hak;Choi, Jin-Hyuk;Lee, Young-Ok
    • Journal of applied mathematics & informatics
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    • v.27 no.3_4
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    • pp.857-864
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    • 2009
  • The special conformally flatness is a generalization of a sub-projective space. B. Y. Chen and K. Yano ([4]) showed that every canal hypersurface of a Euclidean space is a special conformally flat space. In this paper, we study the conditions for the base space B is special conformally flat in the conharmonically flat warped product space $B^n{\times}f\;R^1$.

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Conformally invariant tensors on hermitian manifolds

  • Matsuo, Koji
    • Bulletin of the Korean Mathematical Society
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    • v.33 no.3
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    • pp.455-463
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    • 1996
  • In [3] and [4], Kitahara, Pak and the author obtained the conformally invariant tensor $B_0$, which is an algebraic Hermitian analogue of the Weyl conformal curvature tensor W in the Riemannian geometry, by the decomposition of the curvature tensor H of the Hermitian connection and the notion of semi-curvature-like tensors of Tanno (see[7]). In [5], the author defined a conformally invariant tensor $B_0$ on a Hermitian manifold as a modification of $B_0$. Moreover he introduced the notion of local conformal Hermitian-flatness of Hermitian manifolds and proved that the vanishing of this tensor $B_0$ together with some condition for the scalar curvatures is a necessary and sufficient condition for a Hermitian manifold to be locally conformally Hermitian-flat.

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On Generalized Ricci Recurrent Spacetimes

  • Dey, Chiranjib
    • Kyungpook Mathematical Journal
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    • v.60 no.3
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    • pp.571-584
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    • 2020
  • The object of the present paper is to characterize generalized Ricci recurrent (GR4) spacetimes. Among others things, it is proved that a conformally flat GR4 spacetime is a perfect fluid spacetime. We also prove that a GR4 spacetime with a Codazzi type Ricci tensor is a generalized Robertson Walker spacetime with Einstein fiber. We further show that in a GR4 spacetime with constant scalar curvature the energy momentum tensor is semisymmetric. Further, we obtain several corollaries. Finally, we cite some examples which are sufficient to demonstrate that the GR4 spacetime is non-empty and a GR4 spacetime is not a trivial case.