Results 11 to 20 of about 933 (70)

A remark on four‐dimensional almost Kähler‐Einstein manifolds with negative scalar curvature

International Journal of Mathematics and Mathematical Sciences, Volume 2004, Issue 35, Page 1837-1842, 2004., 2004
Concerning the Goldberg conjecture, we will prove a result obtained by applying the result of Iton in terms of L2‐norm of the scalar curvature.
R. S. Lemence, T. Oguro, K. Sekigawa
wiley   +1 more source

A Kähler Einstein structure on the tangent bundle of a space form

International Journal of Mathematics and Mathematical Sciences, Volume 25, Issue 3, Page 183-195, 2001., 2001
We obtain a Kähler Einstein structure on the tangent bundle of a Riemannian manifold of constant negative curvature. Moreover, the holomorphic sectional curvature of this Kähler Einstein structure is constant. Similar results are obtained for a tube around zero section in the tangent bundle, in the case of the Riemannian manifolds of constant positive ...
Vasile Oproiu
wiley   +1 more source

Totally real submanifolds in a complex projective space

International Journal of Mathematics and Mathematical Sciences, Volume 22, Issue 1, Page 205-208, 1999., 1999
In this paper, we establish the following result: Let M be an n‐dimensional complete totally real minimal submanifold immersed in CPn with Ricci curvature bounded from below. Then either M is totally geodesic or inf r ≤ (3n + 1)(n − 2)/3, where r is the scalar curvature of M.
Liu Ximin
wiley   +1 more source

On the Hermitian structures of the sequence of tangent bundles of an affine manifold endowed with a Riemannian metric

Complex Manifolds, 2022
Let (M, ∇, 〈, 〉) be a manifold endowed with a flat torsionless connection r and a Riemannian metric 〈, 〉 and (TkM)k≥1 the sequence of tangent bundles given by TkM = T(Tk−1M) and T1M = TM. We show that, for any k ≥ 1, TkM carries a Hermitian structure (Jk,
Boucetta Mohamed
doaj   +1 more source

On some compact almost Kähler locally symmetric space

International Journal of Mathematics and Mathematical Sciences, Volume 21, Issue 1, Page 69-72, 1998., 1997
In the framework of studying the integrability of almost Kähler manifolds, we prove that if a compact almost Kähler locally symmetric space M is a weakly ,∗‐Einstein vnanifold with non‐negative ,∗‐scalar curvature, then M is a Kähler manifold.
Takashi Oguro
wiley   +1 more source

On CR‐submanifolds of the six‐dimensional sphere

International Journal of Mathematics and Mathematical Sciences, Volume 18, Issue 1, Page 201-203, 1995., 1995
We consider proper CR‐submanifolds of the six‐dimensional sphere S6. We prove that S6 does not admit compact proper CR‐submanifolds with non‐negative sectional curvature and integrable holomorphic distribution.
M. A. Bashir
wiley   +1 more source

CR‐hypersurfaces of the six‐dimensional sphere

International Journal of Mathematics and Mathematical Sciences, Volume 17, Issue 1, Page 197-200, 1994., 1994
We proved that there does not exist a proper CR‐hypersurface of S6 with parallel second fundamental form. As a result of this we showed that S6 does not admit a proper CR‐totally umbilical hypersurface. We also proved that an Einstein proper CR‐hypersurface of S6 is an extrinsic sphere.
M. A. Bashir
wiley   +1 more source

Locally conformal symplectic nilmanifolds with no locally conformal Kähler metrics

Complex Manifolds, 2017
We report on a question, posed by L. Ornea and M. Verbitsky in [32], about examples of compact locally conformal symplectic manifolds without locally conformal Kähler metrics.
Bazzoni Giovanni, Marrero Juan Carlos
doaj   +1 more source

CR‐hypersurfaces of complex projective space

International Journal of Mathematics and Mathematical Sciences, Volume 17, Issue 3, Page 613-616, 1994., 1994
We consider compact n‐dimensional minimal foliate CR‐real submanifolds of a complex projective space. We show that these submanifolds are great circles on a 2‐dimensional sphere provided that the square of the length of the second fundamental form is less than or equal to n − 1.
M. A. Bashir
wiley   +1 more source

Stenzel's Ricci-flat Kaehler metrics are not projectively induced [PDF]

, 2020
We investigate the existence of a holomorphic and isometric immersion in the complex projective space for the complete Ricci-flat Kaehler metrics constructed by M. B.
Zedda, Michela
core   +1 more source