In this paper we study the cohomogeneity one de Sitter space S1 n. We consider the actions in both proper and non-proper cases. In the first case we characterize the acting groups and orbits and we prove that the orbi...In this paper we study the cohomogeneity one de Sitter space S1 n. We consider the actions in both proper and non-proper cases. In the first case we characterize the acting groups and orbits and we prove that the orbit space is homeomorphic to R. In the latter case we determine the groups and consequently the orbits in some different cases and prove that the orbit space is not Hausdorff.展开更多
利用Arnol'd的Legendrian理论,对三维Anti de Sitter空间中Lorentzian曲面进行了研究.引入光维高度函数概念研究了三维Anti de Sitter空间Lorentzian曲面的S1t×S1s-值、光锥Gauss映射的奇点,进行了奇点分类,揭示了类光Causs-kr...利用Arnol'd的Legendrian理论,对三维Anti de Sitter空间中Lorentzian曲面进行了研究.引入光维高度函数概念研究了三维Anti de Sitter空间Lorentzian曲面的S1t×S1s-值、光锥Gauss映射的奇点,进行了奇点分类,揭示了类光Causs-kronecker曲率之间的关系;并研究了Lorentzian曲面的一些基本几何性质.展开更多
基金Supported by Iranian Presidential Office (Grant No. 83211)
文摘In this paper we study the cohomogeneity one de Sitter space S1 n. We consider the actions in both proper and non-proper cases. In the first case we characterize the acting groups and orbits and we prove that the orbit space is homeomorphic to R. In the latter case we determine the groups and consequently the orbits in some different cases and prove that the orbit space is not Hausdorff.
文摘利用Arnol'd的Legendrian理论,对三维Anti de Sitter空间中Lorentzian曲面进行了研究.引入光维高度函数概念研究了三维Anti de Sitter空间Lorentzian曲面的S1t×S1s-值、光锥Gauss映射的奇点,进行了奇点分类,揭示了类光Causs-kronecker曲率之间的关系;并研究了Lorentzian曲面的一些基本几何性质.
