Results 51 to 60 of about 272 (159)

Ghosts in metric-affine higher order curvature gravity

European Physical Journal C: Particles and Fields, 2019
We disprove the widespread belief that higher order curvature theories of gravity in the metric-affine formalism are generally ghost-free. This is clarified by considering a sub-class of theories constructed only with the Ricci tensor and showing that ...
Jose Beltrán Jiménez, Adria Delhom
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On a Type of Projective Semi- Symmetric Connection

International Journal of Analysis and Applications, 2015
In the present paper, we have studied some properties of curvature tensors of special projective semi-symmetric connection. We have shown that curvature tensor of such a connection satisfies Bianchi's identities.
S. K. Pal, M. K. Pandey, R. N. Singh
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A Note On The Quasi-Conformal And M-Projective Curvature Tensor Of A Semi-Symmetric Recurrent Metric Connection On A Riemannian Manifold

Süleyman Demirel Üniversitesi Fen-Edebiyat Fakültesi Fen Dergisi, 2013
: In the present note we have considered Mn to be a Riemannian manifold admitting a semi-symmetric recurrent metric connection. The aim of the present paper is to obtain the conditions under which the quasi-conformal curvature tensor and M-projective ...
Rajesh Kumar, Jagannath Chowdhury
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Instabilities in metric-affine theories of gravity with higher order curvature terms

European Physical Journal C: Particles and Fields, 2020
We discuss the presence of ghostly instabilities for metric-affine theories constructed with higher order curvature terms. We mainly focus on theories containing only the Ricci tensor and show the crucial role played by the projective symmetry.
Jose Beltrán Jiménez, Adrià Delhom
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A Note on the Geometry of RW Space-Times

Mathematics, 2023
A conformally flat GRW space-time is a perfect fluid RW space-time. In this note, we investigated the influence of many differential curvature conditions, such as the existence of recurrent and semi-symmetric curvature tensors.
Sameh Shenawy, Uday Chand De, Nasser Bin Turki   +2 more
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Some Remarks on Fourth-Order Tensor Fields on Space-Times

Mathematics
This paper is a contribution to Einstein’s general relativity theory and is mostly a review of known work. It concentrates attention on four fourth-order tensors which arise on the space-time manifold describing this theory and which are very useful ...
Graham Hall
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Hierarchy of spaces of projective connection

Дифференциальная геометрия многообразий фигур, 2018
We consider the bundle of projective frames over a smooth manifold, i. e. the principal bundle whose typical fiber is the projective group. The giving fundamental-group connection in this bundle transforms it into a space of general projective connection.
Yu. Shevchenko
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On Almost C(α)-Manifold Satisfying Certain Curvature Conditions

Cumhuriyet Science Journal
This research article is about the geometry of the almost C(α)- manifold. Some important properties of the almost C(α)- manifold with respect to the W_3- curvature tensor, such as W_3-flat and W_3- semi-symmetry, are investigated.
Pakize Uygun, Tuğba Mert, Mehmet Atçeken   +2 more
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Index of pseudo-projectively-symmetric semi-Riemannian manifolds

Karpatsʹkì Matematičnì Publìkacìï, 2015
The index of $\widetilde{\nabla}$-pseudo-projectively symmetric and in particular for $\widetilde{\nabla}$-projectively symmetric semi-Riemannian manifolds, where $\widetilde{\nabla}$ is Ricci symmetric metric connection, are discussed.
P. Gupta
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Some Identities for Generalized Curvature Tensors in 𝓑-Recurrent Finsler Space

Journal of New Theory, 2020
The purpose of the present paper is to consider and study a certain identities for some generalized curvature tensors in ℬ-recurrent Finsler space 𝐹𝑛 in which Cartan’s second curvature tensor 𝑃𝑗𝑘ℎ𝑖 satisfies the generalized of recurrence condition with ...
Adel Mohammed Ali Al-qashbari
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