Results 71 to 80 of about 2,217 (169)

Hidden Symmetries of Euclideanised Kerr-NUT-(A)dS Metrics in Certain Scaling Limits

open access: yesSymmetry, Integrability and Geometry: Methods and Applications, 2012
The hidden symmetries of higher dimensional Kerr-NUT-(A)dS metrics are investigated. In certain scaling limits these metrics are related to the Einstein-Sasaki ones.
Mihai Visinescu, Eduard Vîlcu
doaj   +1 more source

Kählerity of Einstein four-manifolds

open access: yesMathematische Zeitschrift
We prove that a closed oriented Einstein four-manifold is either anti-self-dual or (after passing to a double Riemann cover if necessary) Kähler-Einstein, provided that $λ_2 \geq -\frac{S}{12}$, where $λ_2$ is the middle eigenvalue of the self-dual Weyl tensor $W^+$ and $S$ is the scalar curvature.
Li, Xiaolong, Zhang, Yongjia
openaire   +4 more sources

AInstein: numerical Einstein metrics via machine learning

open access: yesAI for Science
A new semi-supervised machine learning package is introduced which successfully solves the Euclidean vacuum Einstein equations with a cosmological constant, without any symmetry assumptions.
Edward Hirst   +2 more
doaj   +1 more source

Pseudo-Einstein manifolds

open access: yesTopology and its Applications, 2015
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
openaire   +2 more sources

LP-Kenmotsu Manifolds Admitting Bach Almost Solitons

open access: yesUniversal Journal of Mathematics and Applications
For a Lorentzian para-Kenmotsu manifold of dimension $m$ (briefly, ${(LPK)_{m}}$) admitting Bach almost soliton $(g,\zeta,\lambda)$, we explored the characteristics of the norm of Ricci operator. Besides, we gave the necessary condition for ${(LPK)_{m}}
Mohd Bilal   +4 more
doaj   +1 more source

Novel Theorems on Spacetime Admitting Pseudo-W2 Curvature Tensor

open access: yesJournal of Mathematics
This paper investigates spacetime manifolds admitting a pseudo-W2 curvature tensor. We show that a pseudo-W2 flat spacetime is an Einstein manifold and therefore has constant curvature.
B. B. Chaturvedi   +2 more
doaj   +1 more source

The failure of the Ehlers-Kundt conjecture in the impulsive case. [PDF]

open access: yesGen Relativ Gravit
Frauenberger ML   +2 more
europepmc   +1 more source

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