Results 51 to 60 of about 3,286,440 (286)

Complete spacelike hypersurfaces with positive r-th mean curvature in a semi-Riemannian warped product

open access: yesAnalele Stiintifice ale Universitatii Ovidius Constanta: Seria Matematica, 2015
In this paper, by supposing a natural comparison inequality on the positive r-th mean curvatures of the hypersurface, we obtain some new Bernstein-type theorems for complete spacelike hypersurfaces immersed in a semi-Riemannian warped product of constant
Wang Yaning, Liu Ximin
doaj   +1 more source

The geometry of warped product singularities [PDF]

open access: yesInternational Journal of Geometric Methods in Modern Physics, 2017
In this article, the degenerate warped products of singular semi-Riemannian manifolds are studied. They were used recently by the author to handle singularities occurring in General Relativity, in black holes and at the big-bang. One main result presented here is that a degenerate warped product of semi-regular semi-Riemannian manifolds with the ...
openaire   +2 more sources

Warped product rigidity [PDF]

open access: yesAsian Journal of Mathematics, 2015
In this paper we study the space of solutions to an overdetermined linear system involving the Hessian of functions. We show that if the solution space has dimension greater than one, then the underlying manifold has a very rigid warped product structure.
He, Chenxu   +2 more
openaire   +2 more sources

Killing tensors and warped product [PDF]

open access: yesAnnales Polonici Mathematici, 2000
By a Killing tensor one understands a \((1,1)\)-tensor field \(S\) on a Riemannian manifold \((M,g)\) satisfying the conditions \(\langle SX,Y \rangle =\langle X,S Y\rangle\) and \(\langle\nabla S(X,X),X \rangle=0\), for all \(X\) on \(M\). Considering the eigenvalues and the eigendistributions of \(S\), the author gets close relations between certain ...
openaire   +1 more source

Einstein Hypersurfaces of Warped Product Spaces

open access: yesResults in Mathematics, 2022
We consider Einstein hypersurfaces of warped products $I\times_ω\mathbb Q_ε^n,$ where $I\subset\mathbb R$ is an open interval and $\mathbb Q_ε^n$ is the simply connected space form of dimension $n\ge 2$ and constant sectional curvature $ε\in\{-1,0,1\}.$ We show that, for all $c\in\mathbb R$ (resp.
R. F. de Lima   +2 more
openaire   +3 more sources

Warping functions of some warped products

open access: yesJournal of Mathematical Analysis and Applications, 2014
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
openaire   +2 more sources

Spatial and Volumetric Characteristics of Glioblastoma: Associations With Clinical Presentation and Survival

open access: yesAnnals of Clinical and Translational Neurology, EarlyView.
ABSTRACT Objective We aim to comprehensively analyze how regional tumor and edema characteristics are associated with clinical presentations and survival outcomes in a large cohort of glioblastoma patients. Methods Patients with IDH‐wildtype glioblastoma who received brain MRI from 2010 to 2023 were included.
Daniel J. Zhou   +16 more
wiley   +1 more source

Multiply warped products with compact Einstein manifolds

open access: yes, 2021
We study multiply warped products with compact Einstein manifolds. We obtain that there does not exist connected, compact Einstein  multiply warped products if the scalar curvature is non-positive.
Karaca, Fatma
core  

Geometric Classification of Warped Products Isometrically Immersed into Conformal Sasakian Space Froms

open access: yes, 2022
Warped products play important roles in differential geometry, general relativity, and symmetry science. In this paper, we study the warped product pointwise semi-slant submanifolds that are isometrically immersed into conformal Sasakian space form.
Mehraj Ahmad Lone   +4 more
core   +1 more source

Diffusion Basis Spectrum Imaging of Tissue Microstructure and Early Treatment in Multiple Sclerosis

open access: yesAnnals of Clinical and Translational Neurology, EarlyView.
ABSTRACT Objective Conventional MRI cannot resolve the coexisting pathological processes within multiple sclerosis tissue. Diffusion Basis Spectrum Imaging decomposes the diffusion signal into fiber, cell, and hindered ratios indexing axonal integrity, cellularity, and extracellular space, respectively.
Apisit Kaewsanit   +10 more
wiley   +1 more source

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