T2m×R2n上阿诺德弦猜想中的变分方法

本文用变分方法证明T2m ×R2n 上限定型的勒让德子流形至少存在一个Reeb弦连结它 .另外 ,也把阿诺德弦猜想推广到非切触流形并证明了一些结论     

Sasakian切触度量(κ,μ)-空间中子流形的分类

特征矢量场属于某（κ，μ）－幂零分布的切触度量流形称为切触度量（κ，μ）空间，本文中我们证明了当κ^2 μ^2≠0时，一个非Sasakian切触度量（κ，μ）－空间中的任何子流形要么是不变的全测地子流形。要么为反不变子流形。     

近切触流形的φ~*-解析向量场（英文）

本文引入了近切触流形(M,φ,ξ,η,g)中φ~*-解析向量场的概念,并研究了其性质.利用近切触流形的性质,证明了切触度量流形中的φ~*-解析向量场v是Killing向量场且φv不是φ*-解析的.特别地,如果近切触流形M是正规的,得到v与ξ平行且模长为常数.另外,证明了3维的切触度量流形不存在非零的φ~*-解析向量场.     

近切触流形的φ*-解析向量场

本文引入了近切触流形（M,ø,ξ,η,g）中φ^*-解析向量场的概念,并研究了其性质.利用近切触流形的性质,证明了切触度量流形中的φ^*-解析向量场v是Killing向量场且φv不是φ^*-解析的.特别地,如果近切触流形M是正规的,得到v与ξ平行且模长为常数.另外,证明了3维的切触度量流形不存在非零的φ^*-解析向量场.     

共形对称的K—切触流形

本文建立了共形平坦的K－切触流形的纯量曲率适合的偏微分方程，证得：共形对称的K－切触流形是具常曲率1的Riemann流形，将Okumura和Miyazaawa等人的有关Sasaki流形的结果推广到K－切触流形。     

Riemann流形上的一类标准共形不变度量

任意紧Riemann面上都存在一个仅依赖于共形类且拥有常曲率的度量.Harbermann和Jost用Yamabe算子对应的Green函数在数量曲率为正的局部共形平坦流形上构造了一个标准共形不变度量.在此之后,这类标准共形不变度量被推广到了数量曲率为正的球型CR流形上.进一步的,应用相应的Yamabe算子对应的Green函数可以构造数量曲率为正的球型四元切触流形和数量曲率为正的八元切触流形上类似的标准共形不变张量.在四元切触正质量猜测和八元切触正质量猜测成立的前提下,上述共形不变张量是共形不变度量.文中利用Paneitz算子对应的Green函数在局部共形平坦流形上构造了一类上述标准共形不变张量,并且在一定条件(详见定理3.1)下,该标准共形不变张量进一步为标准共形不变度量.     

关于切丛和单位切球丛的度量的一个注记

本文在黎曼流形$(M,g)$的切丛$TM$ 上研究与参考文献[10]中平行的一类度量$G$以及相容的近复结构$J$.证明了切丛$TM$关于这些度量和相应的近复结构是局部共形近K\"{a}hler流形,并且把这些结构限制在单位切球丛上得到了切触度量结构的新例子.     

四维Anti deSitter空间中类空曲面的null超曲面的奇点

定义了类空超曲面上的null超曲面映射及距离平方函数,证明了距离平方函数是Morse族,并应用Arnold等建立的Legendrian奇点理论和流形间的切触理论对四维Anti de Sitter空间中的类空曲面的null超曲面及切nullcone指标线的奇点进行了研究.     

切触黎曼浸入的极小性

切触黎曼流形,其殆复结构不一定是可积的,是CR几何中伪厄尔米特流形的一般情形.选取TWT联络作为切触黎曼流形上的联络,在CR情形下它就是TW联络.推广CR几何中的伪厄尔米特浸入得到切触黎曼几何中的切触黎曼浸入,可以证明任何切触黎曼浸入一定是极小的.     

一般状态空间上m—tight过程的首触时容度的表示及应用

该文证明了一般状态空间上由m-tight过程的首触时导出的容度可直接地由相应集合的首触时通过积分表示出来，利用这一结果，我们证明了函数是拟连续的几个等价命题．     

Handle attaching in symplectic homology and the Chord Conjecture

Arnold conjectured that every Legendrian knot in the standard contact structure on the 3-sphere possesses a characteristic chord with respect to any contact form. I confirm this conjecture if the know has Thurston-Bennequin invariant −1. More generally, existence of chords is proved for a standard Legendrian unknot on the boundary of a subcritical Stein manifold of any dimension. There is also a multiplicity result which implies in some situations existence of infinitely many chords.?The proof relies on the behaviour of symplectic homology under handle attaching. The main observation is that symplectic homology only changes in the presence of chords. Received July 14, 2000 / final version received June 1, 2001?Published online August 1, 2001     

R3中双弦幂积分

本文研究R3中凸体的双弦幂积分,利用线偶的运动密度,得到了一些性质及球体上的部分双弦幂积分值,并由此解决了R3中一几何概率问题.     

随机弦长矩与弦幂积分

本文研究了凸体的五种类型的随机弦长分布.利用限弦投影原理和运动测度积分的方法,揭示了凸体的弦幂积分与随机弦长的矩之间的本质联系.     

Recognition of triangles by covariogram

The paper considers the problem of recognition of triangles by orientation-dependent chord length distribution. The following results are obtained: 1. The explicit form of the covariogram and orientation-dependent chord length distribution function for a triangle. 2. The explicit form for the chord length distribution function for a triangle. 3. The length of the maximal chord of a triangle is continuous function on direction u ∈ S ¹ (S ¹ is the space of all directions in the plane). 4. If we have orientation-dependent chord length distribution function for an everywhere dense set of S ¹, then we can uniquely recognize the triangle with respect to reflections and translations. 5. For any finite subset A ? S ¹, there are two non-congruent triangles with the same values of orientationdependent chord length distribution functions on A.     

Orientation-dependent section distributions for convex bodies

In the paper the orientation dependent chord length distribution functions for some bounded convex domains are obtained. In particular, formulae for the orientation dependent chord length distributions for a regular polygon and an ellipse are obtained. Explicit forms of the orientation dependent chord length distributions were known only in the cases of a disc and a triangle. We also obtain the cross-section area distribution functions for an ellipsoid and a cylinder. The cross-section area distribution function was known only in the case of a ball.     

SOME DUAL KINEMATIC FORMULAS

In this article, some kinematic formulas for dual quermassintegral of star bodies and for chord power integrals of convex bodies are established by using dual mixed volumes. These formulas are the extensions of the fundamental kinematic formula involving quermassintegral to the case of dual quermassintegral and chord power integrals.     

凸体的弦幂积分公式

本文研究了高维欧氏空间中凸体的弦幂积分问题.利用积分的方法,获得了凸体弦幂积分的几个积分公式.     

Covariogram of a parallelogram

In this paper we obtain the explicit forms of the covariogram and the orientation-dependent chord length distribution function for any parallelogram. The explicit form of the chord length distribution function for a parallelogram is also obtained.