Results 21 to 30 of about 32,038 (159)

Lightlike Hypersurfaces and Time-Minimizing Geodesics in Cone Structures

, 2022
Some well-known Lorentzian concepts are transferred into the more general setting of cone structures, which provide both the causality of the spacetime and the notion of cone geodesics without making use of any metric. Lightlike hypersurfaces are defined within this framework, showing that they admit a unique folitation by cone geodesics. This property
Javaloyes, Miguel Ángel, Pendás-Recondo, Enrique   +1 more
openaire   +3 more sources

Connection by geodesics on globally hyperbolic spacetimes with a lightlike Killing vector field

, 2014
Given a globally hyperbolic spacetime endowed with a complete lightlike Killing vector field and a complete Cauchy hypersurface, we characterize the points which can be connected by geodesics.
R. Bartolo, A. M. Candela, J. Flores
semanticscholar   +2 more sources

Totally Umbilical Lightlike Hypersurfaces in Robertson-Walker Spacetimes [PDF]

ISRN Geometry, 2014
We study the problem of lightlike hypersurface immersed into Robertson-Walker (RW) spacetimes in this paper, where the screen bundle of the hypersurface has constant higher order mean curvature. We consider the following question: under what conditions is the compact lightlike hypersurface totally umbilical?
Dong, Junhong, Liu, Ximin
openaire   +2 more sources

PSEUDOSYMMETRIC LIGHTLIKE HYPERSURFACES IN INDEFINITE SASAKIAN SPACE FORMS

Journal of Applied Analysis & Computation, 2016
Summary: We study pseudosymmetric lightlike hypersurfaces of an indefinite Sasakian space form, tangent to the structure vector field. We obtain sufficient conditions for a lightlike hypersurface to be pseudosymmetric, pseudoparallel and Ricci-pseudosymmetric in an indefinite Sasakian space form.
Kazan, Sema, Ṣahin, Bayram
openaire   +2 more sources

Codimension-two spacelike submanifolds with umbilical lightlike normal sections and their relationship to lightlike hypersurfaces

Classical and Quantum Gravity
Abstract We study codimension-two spacelike submanifolds in Lorentzian spacetimes that admit umbilical lightlike normal directions. We show that such submanifolds are subject to strong geometric and topological constraints, establishing explicit relationships between extrinsic geometry, mean curvature, and shear-isotropy.
J. Gómez
openaire   +3 more sources

Perturbative Solution of the Einstein Constraints with Spin and Momentum Far Away From a Binary Source in the Bowen‐York Formalism

Fortschritte der Physik, Volume 71, Issue 8-9, September 2023., 2023
Abstract The momentum and Hamiltonian constraints of vacuum Einstein equations, within the Bowen‐York formalism, for two interacting black holes in close separation, with anti‐parallel spins and anti‐parallel linear momenta is studied. An analytical solution using perturbation theory is given.
Emel Altas, Emine Ertugrul, Bayram Tekin
wiley   +1 more source

LIGHTLIKE HYPERSURFACES OF ALMOST NORDEN GOLDEN SEMI-RIEMANNIAN MANIFOLDS [PDF]

, 2022
In this paper, we give some classifications about lightlike hypersurfaces of almost Norden Golden semi-Riemannian manifolds. We show that, there is no radical anti-invariant lightlike hypersurfaces of an almost Norden Golden semi-Riemannian manifold ...
Bozdağ, Şerife Nur, Erdoğan, Feyza Esra, Yüksel Perktaş, Selcen, Acet, Bilal Eftal   +3 more
core   +1 more source

A New Approach to Timelike Hypersurfaces of Constant Ratio in IE14

Journal of Mathematics, Volume 2023, Issue 1, 2023., 2023
In this study, we consider timelike revolution hypersurfaces of constant ratio in Minkowski space‐time. At first, we exhibit the representations of revolution hypersurfaces given by three different forms. Then, we yield the conditions for such hypersurfaces to correspond to constant ratio surface.
Sezgin Büyükkütük, Francisco J. Garcia Pacheco   +1 more
wiley   +1 more source

Temporary Singularities and Axions: An Analytic Solution that Challenges Charge Conservation

Annalen der Physik, Volume 533, Issue 6, June 2021., 2021
Is charge conservation sacrosact? If so, why? Even when local charge conservation remains in force, the presence of a temporary singularity can give rise to surprising results. This work shows how global charge conservation can be broken after the combined appearance of both new charge and an axion‐like field from the singularity.
Jonathan Gratus, Paul Kinsler, Martin W. McCall   +2 more
wiley   +1 more source

A New Class of Contact Pseudo Framed Manifolds with Applications

International Journal of Mathematics and Mathematical Sciences, Volume 2021, Issue 1, 2021., 2021
In this paper, we introduce a new class of contact pseudo framed (CPF)‐manifolds (M, g, f, λ, ξ) by a real tensor field f of type (1,1), a real function λ such that f3 = λ2f where ξ is its characteristic vector field. We prove in our main Theorem 2 that M admits a closed 2‐form Ω if λ is constant.
K. L. Duggal, Luca Vitagliano
wiley   +1 more source