Results 241 to 250 of about 28,343 (263)

Negative ξ-sectional Curvature

2002
The purpose of this chapter is to introduce some special directions that belong to the contact subbundle of a contact metric manifold with negative sectional curvature for plane sections containing the characteristic vector field ξ or more generally when the operator h admits an eigenvalue greater than 1; these directions were introduced by the author ...
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Sectional-curvature preserving skinning surfaces

Computer Aided Geometric Design, 1996
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Panagiotis D. Kaklis, Alexandros I. Ginnis   +1 more
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Vertical sectional curvature and K-contactness

Journal of Geometry, 1995
Let \((M, \alpha)\) be a contact manifold. The contact form \(\alpha\) is said to be \(K\)-contact if there exists a contact metric \(g\) which is invariant under the characteristic vector field \(v\) of \(\alpha\), i.e. \({\mathcal L}_v g= 0\). The author writes that there seems to be a confusion in the literature whether or not the requirement on \(g\
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Pinching the Sectional Curvature on Open Manifolds

The Journal of Geometric Analysis, 2017
In this paper, the author proves the following theorem: Theorem. Let \(M\) be an open manifold. Given \(\delta >0\) and \(a\in R\), there exists a Riemannian metric on \(M\) such that all sectional curvatures are in \((a-\delta, a+\delta)\).
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Sectional Curvature. Spaces of Constant Curvature. Weyl Hypothesis

1997
As we have seen, by introducing the notion of curvature tensor K ∇, with any pair of tangent vectors Y, Z ∈ T x M we associated a linear transformation K x (Y, Z) of the tangent space T x M. Let F x be an oriented plane spanned by Y, Z (that is, Y, Z are basis vectors in F x .) Let S F be a surface (in M) generated by geodesics tangent to F, more ...
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On Hypersurfaces with no Negative Sectional Curvatures

American Journal of Mathematics, 1960
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Characterizations of a Spacetime of Quasi‐Constant Sectional Curvature and F(R)$\mathcal {F}(\mathcal {R})$‐Gravity

Fortschritte Der Physik, 2023
Uday Chand De, Krishnendu De, Fusun Özen Zengin   +2 more
exaly  

Sectional curvature in general relativity

General Relativity and Gravitation, 1987
G S Hall, Hall G S
exaly  

Kähler parabolicity and the Euler number of compact manifolds of non-positive sectional curvature

Mathematische Annalen, 2001
Frederico Xavier, Cao Jianguo, Xavier Frederico   +2 more
exaly  

Damage detection of tunnel based on the high-density cross-sectional curvature obtained using strain data from BOTDA sensors

Mechanical Systems and Signal Processing, 2021
exaly