scholarly journals A new characterization of geodesic spheres in the hyperbolic space

2016 ◽  
Vol 144 (7) ◽  
pp. 3077-3084
Author(s):  
Jie Wu
Keyword(s):  
Hyperbolic Space ◽  
Geodesic Spheres

scholarly journals An integral formula for compact hypersurfaces in space forms and its applications

2003 ◽  
Vol 74 (2) ◽  
pp. 239-248 ◽  
Author(s):  
Luis J. Alías
Keyword(s):  
Scalar Curvature ◽  
Integral Formula ◽  
Flat Space ◽  
Gauss Map ◽  
Ambient Space ◽  
Geodesic Ball ◽  
Space Forms ◽  
Geodesic Spheres

AbstractIn this paper we establish an integral formula for compact hypersurfaces in non-flat space forms, and apply it to derive some interesting applications. In particular, we obtain a characterization of geodesic spheres in terms of a relationship between the scalar curvature of the hypersurface and the size of its Gauss map image. We also derive an inequality involving the average scalar curvature of the hypersurface and the radius of a geodesic ball in the ambient space containing the hypersurface, characterizing the geodesic spheres as those for which equality holds.

scholarly journals Distance functions and umbilic submanifolds of hyperbolic space

1979 ◽  
Vol 74 ◽  
pp. 67-75 ◽  
Author(s):  
Thomas E. Cecil ◽  
Patrick J. Ryan
Keyword(s):  
Riemannian Manifold ◽  
Euclidean Space ◽  
Hyperbolic Space ◽  
Critical Points ◽  
Morse Function ◽  
Complete Riemannian Manifold ◽  
Distance Functions

In 1972, Nomizu and Rodriguez [5] found the following characterization of the complete umbilic submanifolds of Euclidean space.Theorem A. Let Mn, n ≥ 2, be a connected, complete Riemannian manifold isometrically immersed in a Euclidean space Em. Every Morse function of the form Lp has index 0 or n at all of its critical points if and only if Mnis embedded as a Euclidean n-subspace or a Euclidean n-sphere in Em.

scholarly journals Transversal Jacobi Operators in Almost Contact Manifolds

Mathematics ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 31
Author(s):  
Jong Taek Cho ◽  
Makoto Kimura
Keyword(s):  
Riemannian Manifold ◽  
Hyperbolic Space ◽  
Jacobi Operator ◽  
Real Hypersurfaces ◽  
Contact Manifolds ◽  
Jacobi Operators ◽  
Ruled Real Hypersurfaces ◽  
Contact Distribution ◽  
Contact Riemannian Manifold

Along a transversal geodesic γ whose tangent belongs to the contact distribution D, we define the transversal Jacobi operator Rγ=R(·,γ˙)γ˙ on an almost contact Riemannian manifold M. Then, using the transversal Jacobi operator Rγ, we give a new characterization of the Sasakian sphere. In the second part, we characterize the complete ruled real hypersurfaces in complex hyperbolic space.

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