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Given a metric defined on a manifold of dimension three, we study the problem of finding a conformal filling by a Poincar\'e-Einstein metric on a manifold of dimension four. We establish a compactness result for classes of conformally…

Differential Geometry · Mathematics 2026-01-29 Sun-Yung Alice Chang , Yuxin Ge

Einstein's field equations with cosmological constant are analysed for a static, spherically symmetric perfect fluid having constant density. Five new global solutions are described. One of these solutions has the Nariai solution joined on…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Christian G. Boehmer

Any constant-scalar-curvature Kaehler (cscK) metric on a complex surface may be viewed as a solution of the Einstein-Maxwell equations, and this allows one to produce solutions of these equations on any 4-manifold that arises as a compact…

Differential Geometry · Mathematics 2015-05-20 Claude LeBrun

A generalized flag manifold is a homogeneous space of the form $G/K$, where $K$ is the centralizer of a torus in a compact connected semisimple Lie group $G$. We classify all flag manifolds with four isotropy summands and we study their…

Differential Geometry · Mathematics 2019-11-25 Andreas Arvanitoyeorgos , Ioannis Chrysikos

We show that small homogeneous solutions to the Einstein-Boltzmann-scalar field system exist globally towards the future and tend to the de Sitter solution in a suitable sense. More specifically, we assume that the spacetime is of Bianchi…

General Relativity and Quantum Cosmology · Physics 2024-06-18 Ho Lee , Jiho Lee , Ernesto Nungesser

We prove that an n($\geq$ 4)-dimensional compact Bach-flat manifold with positive constant $\sigma_2$ is an Einstein manifold, provided that its Weyl curvature satisfies a suitable pinching condition.

Differential Geometry · Mathematics 2018-10-17 Huiya He , Haiping Fu

The anti-self-dual projection of the spin connections of certain four-dimensional Einstein manifolds can be Abelian in nature. These configurations signify bundle reductions. By a theorem of Kobayashi and Nomizu such a process is predicated…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Chopin Soo

We provide an explicit resolution of the existence problem for extremal Kaehler metrics on toric 4-orbifolds M with second Betti number b2(M)=2. More precisely we show that M admits such a metric if and only if its rational Delzant polytope…

Differential Geometry · Mathematics 2016-11-28 Vestislav Apostolov , David M. J. Calderbank , Paul Gauduchon

We present new rotating black brane solutions which solve Einstein's equations with cosmological constant $\Lambda$ in arbitrary dimension $d$. For negative $\Lambda$, the branes naturally appear in AdS supergravity compactifications, and…

High Energy Physics - Theory · Physics 2010-02-03 Dietmar Klemm

Any oriented $4$-dimensional Einstein metric with semi-definite sectional curvature satisfies the pointwise inequality \[ \frac{|s|}{\sqrt{6}}\geq|W^+|+|W^-|, \] where $s$, $W^+$ and $W^-$ are respectively the scalar curvature, the…

Differential Geometry · Mathematics 2025-03-28 Luca F. Di Cerbo

In the field equations of Einstein-Cartan theory with cosmological constant a static spherically symmetric perfect fluid with spin density satisfying the Weyssenhoff restriction is considered. This serves as a rough model of space filled…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Christian G. Boehmer

The goal of this paper is to study weakly Einstein critical metrics of the volume functional on a compact manifold $M$ with smooth boundary $\partial M$. Here, we will give the complete classification for an $n$-dimensional, $n=3$ or $4,$…

Differential Geometry · Mathematics 2018-09-28 H. Baltazar , A. Da Silva , F. Oliveira

We study the problem of asymptotically flat bi-axially symmetric stationary solutions of the vacuum Einstein equations in $5$-dimensional spacetime. In this setting, the cross section of any connected component of the event horizon is a…

General Relativity and Quantum Cosmology · Physics 2019-09-24 Marcus Khuri , Gilbert Weinstein , Sumio Yamada

The classification of the Einstein spaces with the Stackel metric of the (3.0) has been done. These spaces are invariant under the action of the three-parameter abelian group of motions and belong to the first type Bianchi spaces. Thus the…

Differential Geometry · Mathematics 2025-04-16 V. V. Obukhov

We prove the instability of conformally K\"ahler, compact or ALF Einstein 4-manifolds with nonnegative scalar curvature which are not half conformally flat. This applies to all the known examples of gravitational instantons which are not…

Differential Geometry · Mathematics 2025-02-11 Olivier Biquard , Tristan Ozuch

The Einstein Equation on 4-dimensional Lorentzian manifolds admitting recurrent null vector fields is discussed. Several examples of a special form are constructed. The holonomy algebras, Petrov types and the Lie algebras of Killing vector…

Differential Geometry · Mathematics 2011-08-22 Anton S. Galaev

We give an overview of progress on homogeneous Einstein metrics on large classes of homogeneous manifolds, such as generalized flag manifolds and Stiefel manifolds. The main difference between these two classes of homogeneous spaces is that…

Differential Geometry · Mathematics 2016-05-20 Andreas Arvanitoyeorgos

We establish new existence and non-existence results for positive solutions of the Einstein-scalar field Lichnerowicz equation on compact manifolds. This equation arises from the Hamiltonian constraint equation for the Einstein-scalar field…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Emmanuel Hebey , Frank Pacard , Daniel Pollack

The aim of this paper is to study Seifert bundle structures on simply connected 5--manifolds. We classify all such 5--manifolds which admit a Seifert bundle structure, and in a few cases all Seifert bundle structures are also classified.…

Differential Geometry · Mathematics 2007-05-23 János Kollár

It is shown that there are infinitely many compact orientable smooth 4-manifolds which do not admit Einstein metrics, but nevertheless satisfy the strict Hitchin-Thorpe inequality 2 chi > 3 |tau|. The examples in question arise as…

dg-ga · Mathematics 2008-02-03 Claude LeBrun