Results 11 to 20 of about 156,624 (168)

Generalized Quasi-Einstein Manifolds in Contact Geometry

open access: yesMathematics, 2020
In this study, we investigate generalized quasi-Einstein normal metric contact pair manifolds. Initially, we deal with the elementary properties and existence of generalized quasi-Einstein normal metric contact pair manifolds.
İnan Ünal
doaj   +1 more source

On Submanifolds of $N(k)$-Quasi Einstein Manifolds with a Type of Semi-Symmetric Metric Connection

open access: yesUniversal Journal of Mathematics and Applications, 2020
In this study, we consider the $ N(k)- $quasi Einstein manifolds with respect to a type of semi-symmetric metric connection. We suppose that the generator of $ N(k)- $quasi-Einstein manifolds is parallel with respect to semi-symmetric metric connection
İnan Ünal
doaj   +1 more source

Cosmologies with turning points

open access: yesPhysics Letters B, 2023
We explore singularity-free and geodesically-complete cosmologies based on manifolds that are not quite Lorentzian. The metric can be either smooth everywhere or non-degenerate everywhere, but not both, depending on the coordinate system.
Bob Holdom
doaj   +1 more source

Quasi-Einstein Hypersurfaces of Complex Space Forms

open access: yesAdvances in Mathematical Physics, 2020
Based on a well-known fact that there are no Einstein hypersurfaces in a nonflat complex space form, in this article, we study the quasi-Einstein condition, which is a generalization of an Einstein metric, on the real hypersurface of a nonflat complex ...
Xuehui Cui, Xiaomin Chen
doaj   +1 more source

On static Poincaré-Einstein metrics [PDF]

open access: yesJournal of High Energy Physics, 2015
The classification of solutions of the static vacuum Einstein equations, on a given closed manifold or an asymptotically flat one, is a long-standing and much-studied problem. Solutions are characterized by a complete Riemannian $n$-manifold $(M,g)$ and a positive function $N$, called the lapse.
Galloway, Gregory, Woolgar, Eric
openaire   +2 more sources

Canonical metrics on generalized Hartogs triangles

open access: yesComptes Rendus. Mathématique, 2022
This paper is concerned with the canonical metrics on generalized Hartogs triangles. As main contributions, we first show the existence of a Kähler–Einstein metric on generalized Hartogs triangles.
Bi, Enchao, Hou, Zelin
doaj   +1 more source

Sasaki-Einstein and paraSasaki-Einstein metrics from (\kappa,\mu)-structures [PDF]

open access: yes, 2013
We prove that any non-Sasakian contact metric (\kappa,\mu)-space admits a canonical \eta-Einstein Sasakian or \eta-Einstein paraSasakian metric. An explicit expression for the curvature tensor fields of those metrics is given and we find the values of ...
Alegre   +33 more
core   +2 more sources

General null asymptotics and superrotation-compatible configuration spaces in d ≥ 4

open access: yesJournal of High Energy Physics, 2021
We address the problem of consistent Campiglia-Laddha superrotations in d > 4 by solving Bondi-Sachs gauge vacuum Einstein equations at the non-linear level with the most general boundary conditions preserving the null nature of infinity.
F. Capone
doaj   +1 more source

Symmetries of the Einstein Equations [PDF]

open access: yes, 1993
Generalized symmetries of the Einstein equations are infinitesimal transformations of the spacetime metric that formally map solutions of the Einstein equations to other solutions. The infinitesimal generators of these symmetries are assumed to be local,
Anderson, I. M., Torre, C. G.
core   +6 more sources

Kähler–Einstein metrics on orbifolds and Einstein metrics on spheres

open access: yesCommentarii Mathematici Helvetici, 2007
A construction of Kähler–Einstein metrics using Galois coverings, studied by Arezzo–Ghigi–Pirola, is generalized to orbifolds. By applying it to certain orbifold covers of ℂℙ^n which are trivial set theoretically, one obtains new Einstein metrics on
GHIGI, ALESSANDRO CALLISTO, Kollar, J.
openaire   +5 more sources

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