TRANSVERSAL HALF LIGHTLIKE SUBMANIFOLDS OF AN INDEFINITE SASAKIAN MANIFOLD
TRANSVERSAL HALF LIGHTLIKE SUBMANIFOLDS OF AN INDEFINITE SASAKIAN MANIFOLD
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不定SASAKI流形的横向半光状子流形
DOI：
10.7468/jksmeb.2011.18.1.051
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
D. Jin
中科院分区：
文献类型：
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作者：
D. Jin
抽象的。本文研究了无限Sasakian流形的半类光子流形的几何。根据其结构向量场的形式，无限Sasakian流形的半类光子流形有几种不同的类型。本文研究了两类半光状子流形：切向子流形和半屏蔽半光状子流形。1.半黎曼流形的余维2类光子流形类根据其根分布的秩可分为两类，称为半类光子流形或余迷向子流形[5]。半类光子流形是r-类光子流形[4]的一个特例，使得r = 1，它的几何形式比余同构子流形或类光超曲面的几何形式更一般。许多关于半类光子流形的工作将立即以正式的方式推广到任意r-类光子流形。近年来，许多作者研究了无限Sasakian流形的类光子流形的几何[7，8，9，12].本文研究了无限Sasakian流形的两类半类光子流形，分别命名为切半类光子流形和凸半类光子流形.在第三节中，我们证明了切半类光子流形的三个特征定理：（1）不存在无穷Sasakian流形的屏蔽共形切半类光子流形。(2)不存在无限Sasakian流形的切向半类光子流形使得它的屏分布是全脐的。(3)在第四节中，我们证明了凸半类光子流形的三个特征定理：（1）不存在凸半类光子流形的屏共形凸半类光子流形。(2)不存在半透明屏幕
Abstract. In this paper, we study the geometry of half lightlike sub-manifolds of an indefinite Sasakian manifold. There are several differenttypes of half lightlike submanifolds of an indefinite Sasakian manifold ac-cording to the form of its structure vector field. We study two types ofthem here: tangential and ascreen half lightlike submanifolds. 1. IntroductionThe class of codimension 2 lightlike submanifolds of semi-Riemannian man-ifolds is compose of two classes by virtue of the rank of its radical distribution,which are called half lightlike submanifold or coisotropic submanifold [5]. Halflightlike submanifold is a particular case of r-lightlike submanifold [4] suchthat r = 1 and its geometry is more general form than that of coisotrophicsubmanifolds or lightlike hypersurfaces. Much of the works on half lightlikesubmanifolds will be immediately generalized in a formal way to arbitrary r-lightlike submanifolds. Recently many authors have studied the geometry oflightlike submanifolds of indefinite Sasakian manifolds [7, 8, 9, 12].In this paper, we study two types of half lightlike submanifolds of an indefi-nite Sasakian manifold, named by tangential and ascreen half lightlike subman-ifolds. In Section 3, we prove three characterization theorems for tangentialhalf lightlike submanifolds: (1) There exists no screen conformal tangentialhalf lightlike submanifold of an indefinite Sasakian manifold. (2) There ex-ists no tangential half lightlike submanifold of an indefinite Sasakian manifoldsuch that its screen distribution is totally umbilical. (3) There exists no to-tally umbilical tangential half lightlike submanifold of an indefinite Sasakianmanifold.In Section 4, we prove three characterization theorems for ascreen half light-like submanifolds: (1) There exists no screen conformal ascreen half lightlikesubmanifold of an indefinite Sasakian manifold. (2) There exists no ascreen half
四元数厄密形式与超奇异几何（二）
DOI：
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发表时间：
2016
期刊：
影响因子：
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作者：
Kohno;K.;Y. Tonegawa;Tomoyoshi Ibukiyama
通讯作者：
Tomoyoshi Ibukiyama