Automorphisms and a reduction theorem in a Sasakian space form E2m+1(−3)

1986 ◽  
Vol 145 (1) ◽  
pp. 317-336
Author(s):  
Shōichi Funabashi
2015 ◽  
Vol 2015 ◽  
pp. 1-9
Author(s):  
Dae Ho Jin

We study lightlike hypersurfacesMof an indefinite generalized Sasakian space formM-(f1,f2,f3), with indefinite trans-Sasakian structure of type(α,β), subject to the condition that the structure vector field ofM-is tangent toM. First we study the general theory for lightlike hypersurfaces of indefinite trans-Sasakian manifold of type(α,β). Next we prove several characterization theorems for lightlike hypersurfaces of an indefinite generalized Sasakian space form.


2019 ◽  
Vol 6 (1) ◽  
pp. 279-293 ◽  
Author(s):  
Jong Taek Cho

AbstractFor a contact manifold, we study a strongly pseudo-convex CR space form with constant holomorphic sectional curvature for the Tanaka-Webster connection. We prove that a strongly pseudo-convex CR space form M is weakly locally pseudo-Hermitian symmetric if and only if (i) dim M = 3, (ii) M is a Sasakian space form, or (iii) M is locally isometric to the unit tangent sphere bundle T1(𝔿n+1) of a hyperbolic space 𝔿n+1 of constant curvature −1.


Author(s):  
Mohamed Belkhelfa ◽  
Fatima Zohra Kadi

It is well known that a Sasakian space form is pseudo-symmetric [M. Belkhelfa, R. Deszcz and L. Verstraelen, Symmetry properties of Sasakian space-forms, Soochow J. Math. 31(4) (2005) 611–616], therefore it is Ricci-pseudo-symmetric. In this paper, we proved that a normal complex contact manifold is Ricci-semi-symmetric if and only if it is an Einstein manifold; moreover, we showed that a complex contact space form [Formula: see text] with constant [Formula: see text]-sectional curvature [Formula: see text] is properly Ricci-pseudo-symmetric [Formula: see text] if and only if [Formula: see text]; in this case [Formula: see text]. We gave an example of properly Ricci-pseudo-symmetric complex contact space form. On the other hand, we proved the non-existence of proper pseudo-symmetric ([Formula: see text]) complex contact space form [Formula: see text]


Author(s):  
David E. Blair ◽  
Lieven Vanhecke

SynopsisUsing explicit equations for Jacobi vector fields on a Sasakian space form, we characterise such spaces by means of the shape operator of small geodesic spheres.


Author(s):  
Zahra Nazari ◽  
Esmail Abedi

We are studying Ricci solitons on Hoph hypersurfaces in Sasakian space formfM2n+1(c). The rst, we prove that Hoph hypersurfaces of a Sasakian space formfM2n+1(c < 1) with two distinct principal curvatures is shrinking and for c 1,Hoph hypersurfaces with two distinct principal curvatures of a Sasakian space formfM2n+1(c) does not admit a Ricci soliton. We show that there is not any Hoph hyper-surfaces with two distinct principal curvatures in a Sasakian space form fM2n+1(c)with a -Ricci soliton (and Ricci soliton) such that potential vector eld is the Reebvector eld.Then we prove that Hoph hypersurfaces in Sasakian space form fM2n+1(c) withc = 1 does not admit a - Ricci soliton with potential vector eld U and we showthat Ricci soliton on Hoph hypersurfaces M in Sasakian space form fM2n+1(c <


1984 ◽  
Vol 48 (2) ◽  
pp. 229-240 ◽  
Author(s):  
Aurel Bejancu ◽  
Neculai Papaghiuc

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Rongsheng Ma ◽  
Donghe Pei

In this paper, we investigate the Lorentzian generalized Sasakian-space-form. We give the necessary and sufficient conditions for the Lorentzian generalized Sasakian-space-form to be projectively flat, conformally flat, conharmonically flat, and Ricci semisymmetric and their relationship between each other. As the application of our theorems, we study the Ricci almost soliton on conformally flat Lorentzian generalized Sasakian-space-form.


2021 ◽  
Vol 52 ◽  
Author(s):  
Chawngthu Lalmalsawma ◽  
Jay Prakash Singh

The object of this paper is to study symmetric properties of Sasakian generalized Sasakian-space-form with respect to generalized Tanaka–Webster connection. We studied semisymmetry and Ricci semisymmetry of Sasakian generalized Sasakian-space-form with respect to generalized Tanaka–Webster connection. Further we obtain results for Ricci pseudosymmetric and Ricci-generalized pseudosymmetric Sasakian generalized Sasakian-space-form.


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