The topological-Euclidean space form problem

1978 ◽  
Vol 45 (2) ◽  
pp. 181-192 ◽  
Author(s):  
F. T. Farrell ◽  
W. C. Hsiang
2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Chao Yang ◽  
Jiancheng Liu

In this paper, we show that biharmonic hypersurfaces with at most two distinct principal curvatures in pseudo-Riemannian space form Nsn+1c with constant sectional curvature c and index s have constant mean curvature. Furthermore, we find that such biharmonic hypersurfaces Mr2k−1 in even-dimensional pseudo-Euclidean space Es2k, Ms−12k−1 in even-dimensional de Sitter space Ss2kcc>0, and Ms2k−1 in even-dimensional anti-de Sitter space ℍs2kcc<0 are minimal.


2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Akram Ali ◽  
Fatemah Mofarreh ◽  
Rifaqat Ali ◽  
Irfan Anjum Badruddin

AbstractIn the present paper, we extend the study of (Ali et al. in J. Inequal. Appl. 2020:241, 2020) by using differential equations (García-Río et al. in J. Differ. Equ. 194(2):287–299, 2003; Pigola et al. in Math. Z. 268:777–790, 2011; Tanno in J. Math. Soc. Jpn. 30(3):509–531, 1978; Tashiro in Trans. Am. Math. Soc. 117:251–275, 1965), and we find some necessary conditions for the base of warped product submanifolds of cosymplectic space form $\widetilde{M}^{2m+1}(\epsilon )$ M ˜ 2 m + 1 ( ϵ ) to be isometric to the Euclidean space $\mathbb{R}^{n}$ R n or a warped product of complete manifold N and Euclidean space $\mathbb{R}$ R .


1983 ◽  
Vol 106 (1) ◽  
pp. 135-143 ◽  
Author(s):  
Ib Madsen ◽  
Charles Thomas ◽  
C. Terence C. Wall

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Ibrahim Al-Dayel ◽  
Meraj Ali Khan

Recently, we have obtained Ricci curvature inequalities for skew CR-warped product submanifolds in the framework of complex space form. By the application of Bochner’s formula on these inequalities, we show that, under certain conditions, the base of these submanifolds is isometric to the Euclidean space. Furthermore, we study the impact of some differential equations on skew CR-warped product submanifolds and prove that, under some geometric conditions, the base is isometric to a special type of warped product.


2018 ◽  
Vol 103 (117) ◽  
pp. 223-236 ◽  
Author(s):  
Nurettin Turgay

We first present a survey about recent results on biconservative hypersurfaces in the Minkowski space E4 1, pseudo-Euclidean space E5 2 and Rieamnnian space-form H4. Then we obtain some geometrical properties of these hypersurface families concerning their mean curvature and Gauss map.


2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Rakesh Kumar ◽  
Jasleen Kaur ◽  
R. K. Nagaich

We have studied mixed foliateCR-lightlike submanifolds andCR-lightlike product of an indefinite Kaehler manifold and also obtained relationship between them. Mixed foliateCR-lightlike submanifold of indefinite complex space form has also been discussed and showed that the indefinite Kaehler manifold becomes the complex semi-Euclidean space.


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