Results 151 to 160 of about 369 (176)

On the Submanifolds of an Almost Para-Hermitian Manifold

Acta Mathematica Hungarica, 1999
An almost para-Hermitian manifold \((\overline M,\overline J, \overline g)\) is a differentiable manifold \(\overline M\) endowed with an almost product structure \(\overline J\), that is, a tensor field \(\overline J\) of type \((1,1)\) obeying \(\overline J\circ\overline J=Id\), and a pseudo-Riemannian metric \(\overline g\) such that \(\overline g ...
Etayo, F., Fioravanti, M., Trías, U. R.
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ALMOST EINSTEIN-HERMITIAN MANIFOLDS

JP Journal of Geometry and Topology
In this paper, we show that every almost Einstein-Hermitian 4-manifold (i.e., almost Hermitian 4-manifold with -invariant Ricci tensor and harmonic Weyl tensor) is either Einstein or Hermitian. Consequently, we obtain that any almost Einstein-Hermitian 4-manifold which is not Einstein must be Hermitian and that every almost Einstein-Hermitian 4 ...
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Isometric Immersions of almost Hermitian Manifolds

Canadian Journal of Mathematics, 1969
The Lefschetz theorem on hyperplane sections, as proved by Andreotti and Frankel (1), depends upon the following result.THEOREM. If M is a non-singular affine algebraic variety of real dimension 2k of complex n-space, thenThis theorem, which is interesting in itself, has been strengthened by Milnor (7), who showed that M has the homotopy type of a k ...
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On the Twistor Spaces of Almost Hermitian Manifolds

Annals of Global Analysis and Geometry, 1998
Given an almost Hermitian manifold \((M,g,J)\), denote by \({\mathcal G}_k(M)\) the Grassmann bundle of \(J\)-invariant \(2k\)-subspaces of \(TM\). Any unitary connection \(\omega\) on \(M\) gives rise to a splitting of \(T{\mathcal G}_k(M)\) into vertical and horizontal parts which allows one to introduce four almost complex structures \(J_{\pm}\) and
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THE SPECTRAL GEOMETRY OF SOME ALMOST HERMITIAN MANIFOLDS

SUT Journal of Mathematics, 1996
Let \((M,g,J)\) [resp. \(M',g',J')]\) be a compact almost Hermitian manifold satisfying certain additional conditions, where \(M\) is a \(2n\)-dimensional manifold, \(g\) (resp. \(g')\) a Hermitian metric and \(J\) (resp. \(J')\) an almost Hermitian structure. Almost \(L\) structures [for the definition, see \textit{L.
Hsiung, Chuan-Chih, Yang, Wenmao, Xiong, Bonnie   +2 more
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J-harmonic functions on almost Hermitian manifolds

Differential Geometry and its Applications, 2020
The purpose of this paper is to examine the \(J\)-Laplacian operator \(\Delta_J=\mathrm{div} J \nabla\) acting on smooth functions on an almost Hermitian manifold \((M,J,g)\). Let \(\omega(X,Y)=g(JX,Y)\) be a fundamental 2-form for an almost Hermitian structure. An almost Hermitian manifold is called almost-Kähler if \(d\omega=0\) and it is called semi-
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A report on almost quaternionic Hermitian manifolds

1995
Let \(M^{4n}\) be a \(4n\)-dimensional manifold. An almost hypercomplex Hermitian structure on \(M^{4n}\) is defined by a pair \((H,g)\) on \(M^{4n}\), where \(H=(J_\alpha )_{\alpha =1,2,3}\) is an almost hypercomplex structure on \(M^{4n}\) and \(g\) is a Riemannian metric on \(M^{4n}\) which is Hermitian with respect to \(H\).
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Spectral geometry for almost isospectral hermitian manifolds

Geometriae Dedicata, 1993
The author studies the relationship between the spectral geometry of a Riemannian manifold and its holomorphic geometry. Let \(\lambda_{n}^{p,q}\) be the eigenvalues of the complex Laplacian on forms of type \((p,q)\). One says two Hermitian manifolds are strongly \(\alpha\) isospectral if for all \((p,q)\) \[ sup_{n\rightarrow\infty}\mid\lambda_{n ...
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Complex submanifolds in almost Hermitian manifolds

1987
A complex hypersurface M in an almost Hermitian manifold is called a \(\sigma\)-hypersurface if the second fundamental form \(\sigma\) and the almost complex structure J satisfy \(\sigma (X,JY)=\sigma (JX,Y)=J\sigma (X,Y)\) for X, Y tangent to M. The main purpose of this article is to obtain some equivalent conditions for a \(\sigma\)-hypersurface to ...
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A Subsolution Theorem for the Monge-Ampère Equation over an Almost Hermitian Manifold

Acta Mathematica Scientia, 2022
Jiaogen Zhang
exaly