Displaying similar documents to “On sectional curvatures of ( ε ) -Sasakian manifolds.”

Chen-Ricci inequalities for submanifolds of Riemannian and Kaehlerian product manifolds

Erol Kılıç, Mukut Mani Tripathi, Mehmet Gülbahar (2016)

Annales Polonici Mathematici

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Some examples of slant submanifolds of almost product Riemannian manifolds are presented. The existence of a useful orthonormal basis in proper slant submanifolds of a Riemannian product manifold is proved. The sectional curvature, the Ricci curvature and the scalar curvature of submanifolds of locally product manifolds of almost constant curvature are obtained. Chen-Ricci inequalities involving the Ricci tensor and the squared mean curvature for submanifolds of locally product manifolds...

On K-contact Riemannian manifolds with vanishing E-contact Bochner curvature tensor

Hiroshi Endo (1991)

Colloquium Mathematicae

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For Sasakian manifolds, Matsumoto and Chūman [6] defined the contact Bochner curvature tensor (see also Yano [9]). Hasegawa and Nakane [4] and Ikawa and Kon [5] have studied Sasakian manifolds with vanishing contact Bochner curvature tensor. Such manifolds were studied in the theory of submanifolds by Yano ([9] and [10]). In this paper we define an extended contact Bochner curvature tensor in K-contact Riemannian manifolds and call it the E-contact Bochner curvature tensor. Then we show...

A pinching theorem on complete submanifolds with parallel mean curvature vectors

Ziqi Sun (2003)

Colloquium Mathematicae

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Let M be an n-dimensional complete immersed submanifold with parallel mean curvature vectors in an (n+p)-dimensional Riemannian manifold N of constant curvature c > 0. Denote the square of length and the length of the trace of the second fundamental tensor of M by S and H, respectively. We prove that if S ≤ 1/(n-1) H² + 2c, n ≥ 4, or S ≤ 1/2 H² + min(2,(3p-3)/(2p-3))c, n = 3, then M is umbilical. This result generalizes the...

On some class of pseudosymmetric warped products

Ryszard Deszcz, Dorota Kowalczyk (2003)

Colloquium Mathematicae

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We present curvature properties of pseudosymmetry type of some warped products of semi-Riemannian spaces of constant curvature.

Weyl space forms and their submanifolds

Fumio Narita (2001)

Colloquium Mathematicae

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We study the geometric structure of a Gauduchon manifold of constant curvature. We give a necessary and sufficient condition for a Gauduchon manifold to be a Gauduchon manifold of constant curvature, and we classify the Gauduchon manifolds of constant curvature. Next, we investigate Weyl submanifolds of such manifolds.