Results 191 to 200 of about 823 (221)

Four-Dimensional Almost Kähler Einstein and *-Einstein Manifolds

Geometriae Dedicata, 1998
The Goldberg conjecture [\textit{S. I. Goldberg}, Proc. Am. Math. Soc. 21, 96-100 (1969; Zbl 0174.25002)] states that a compact Einstein almost Kähler manifold is necessarily Kähler. It has been proved that the conjecture holds true if the scalar curvature is nonnegative [\textit{K. Sekigawa}, J. Math. Soc.
Oguro, Takashi, Sekigawa, Kouei
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Super $$\eta $$-Einstein Manifolds

Results in Mathematics
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Pablo Alegre, Alfonso Carriazo, Jong Taek Cho   +2 more
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Compact standard periodic einstein manifolds

Siberian Mathematical Journal, 1992
A Riemannian manifold \(M\) with a metric \(g\) is Einstein if its metric \(g\) satisfies the equation: \(\text{Ric}(g)=Cg\), where Ric is the Ricci tensor of \(M\) and \(C\) is a constant. Let \(G\) be a connected, compact simple Lie group and \(H\) its closed simple subgroup with \(G/H\) simply connected. The homogeneous Riemannian metric induced on \
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Generalized Einstein manifolds

Journal of Geometry and Physics, 1995
The geometrization of physics, especially regarding the equations of electromagnetism and gravitation in general relativity, has been a vital problem of investigation for a long time. A. Einstein himself devoted the last several years of his life to realize this dream without success. However, taking grant of two axioms proposed by \textit{D. Hilbert} [
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On Einstein Hermitian manifolds

Monatshefte für Mathematik, 2007
The author shows that every compact Einstein Hermitian surface with constant *-scalar curvature is Kähler. The *-scalar curvature is the trace of the *-Ricci tensor that measures how far the structure is from being Kähler. When the dimension is \(4n+2\), the author gives an example of an Einstein Hermitian manifold with constant *-scalar curvature that
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Noncompact quasi‐Einstein manifolds conformal to a Euclidean space

Mathematische Nachrichten, 2021
Keti Tenenblat
exaly  

Einstein Manifolds and Topology

1987
Which compact manifolds do admit an Einstein metric? Except in dimension 2 (see Section B of this chapter), a complete answer to this question seems out of reach today. At least, in dimensions 3 and 4, we can single out a few manifolds which definitely do not admit any Einstein metric.
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Homogeneous Einstein and Einstein–Randers metrics on Stiefel manifolds

Mathematische Nachrichten
AbstractWe study invariant Einstein metrics and Einstein–Randers metrics on the Stiefel manifold . We use a characterization for (nonflat) homogeneous Einstein–Randers metrics as pairs of (nonflat) homogeneous Einstein metrics and invariant Killing vector fields.
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The Extension of Einstein Manifolds

1981
Of the many mathematical problems connected with general relativity, the extension problem has been chosen for discussion in this chapter, because it is concerned with the global geometrical and topological properties of Einstein manifolds, and those properties seem to me to constitute the most basically mathematical aspect of the theory.
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On an Einstein projective Sasakian manifold

2006
The author proves that a projectively flat Sasakian manifold is an Einstein manifold. Besides, if an Einstein-Sasakian manifold is projectively flat, then it is locally isometric with a unit sphere \(S^n(1)\). Finally, if in an Einstein-Sasakian manifold the relation \(K(X,Y)\cdot P = 0\) holds, then it is projectively flat.
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