Results 31 to 40 of about 1,087 (98)

A Note on Anti‐De Sitter Spaces as G‐Manifolds

International Journal of Mathematics and Mathematical Sciences, Volume 2025, Issue 1, 2025.
We classify the orbits and orbit spaces of cohomogeneity two isometric actions of compact and connected Lie groups on anti‐de Sitter spaces. We also give a more simple proof for the previously proven theorem about the similar classifications for cohomogeneity one actions.
Jafar Ebrahimi, Reza Mirzaie, Shikha Binwal   +2 more
wiley   +1 more source

Osculating curves in 4-dimensional semi-Euclidean space with index 2

Open Mathematics, 2017
In this paper, we give the necessary and sufficient conditions for non-null curves with non-null normals in 4-dimensional Semi-Euclidian space with indeks 2 to be osculating curves.
İlarslan Kazim, Kiliç Nihal, Erdem Hatice Altin   +2 more
doaj   +1 more source

Curvature estimates for Weingarten hypersurfaces in Riemannian manifolds

, 2008
We prove curvature estimates for general curvature functions. As an application we show the existence of closed, strictly convex hypersurfaces with prescribed curvature $F$, where the defining cone of $F$ is $\C_+$.
Ball J. M., Claus Gerhardt, Ecker K., Gerhardt C.   +3 more
core   +3 more sources

Riemann Solitons on Homogeneous Siklos Spacetimes

Journal of Mathematics, Volume 2025, Issue 1, 2025.
In this paper, we investigate the properties of Riemann solitons on homogeneous Siklos spacetimes. Siklos spacetimes, which are special solutions to Einstein’s equations with a wave‐like potential, provide a suitable setting for studying the geometric properties of Riemann solitons.
Mehdi Jafari, Amirhesam Zaeim, Adele Alemahdi, Erhan Güler   +3 more
wiley   +1 more source

Ricci‐Bourguignon Solitons With Certain Applications to Relativity

Journal of Mathematics, Volume 2025, Issue 1, 2025.
This article concerns with the investigation of Ricci‐Bourguignon solitons and gradient Ricci‐Bourguignon solitons in perfect fluid space‐times and generalised Robertson–Walker space‐times. First, we deduce the criterion for which the Ricci‐Bourguignon soliton in a perfect fluid space‐time is steady, expanding or shrinking. Then, we establish that if a
Krishnendu De, Mohammad Nazrul Islam Khan, Uday Chand De, Yanlin Li, Pramita Mishra   +4 more
wiley   +1 more source

On a Class Almost Contact Manifolds with Norden Metric [PDF]

, 2010
Certain curvature properties and scalar invariants of the manifolds belonging to one of the main classes almost contact manifolds with Norden metric are considered.
Teofilova, Marta
core   +2 more sources

The type N Karlhede bound is sharp

, 2007
We present a family of four-dimensional Lorentzian manifolds whose invariant classification requires the seventh covariant derivative of the curvature tensor.
Boeckx E, Cartan E, Collins J M, MacCallum M A H, Machado Ramos M P, Machado Ramos M P, Milson R Pelavas N, N Pelavas, Ozsváth I, Paiva F M Skea J E F, Pollney D, R Milson, Skea J F, Åman J E   +13 more
core   +1 more source

Linear Connections on Normal Almost Contact Manifolds with Norden Metric [PDF]

, 2010
Families of linear connections are constructed on almost contact manifolds with Norden metric. An analogous connection to the symmetric Yano connection is obtained on a normal almost contact manifold with Norden metric and closed structural 1-form.
Teofilova, Marta
core   +2 more sources

Real hypersurfaces of indefinite Kaehler manifolds

, 1992
International Journal of Mathematics and Mathematical Sciences, Volume 16, Issue 3, Page 545-556, 1993.
A. Bejancu, K. L. Duggal
wiley   +1 more source

Screen Cauchy–Riemann (SCR)-lightlike submanifolds of metallic semi-Riemannian manifolds [PDF]

Arab Journal of Mathematical Sciences
PurposeThe screen Cauchy–Riemann (SCR)-lightlike submanifold is an important class of submanifolds of semi-Riemannian manifolds. It contains various other classes of submanifolds as its sub-cases. It has been studied under various ambient space.
Gauree Shanker, Ankit Yadav, Ramandeep Kaur   +2 more
doaj   +1 more source