双曲空间Hn+1(-1)中完备超曲面

本文研究了双曲空间Hn+1(-1)中具有常数量曲率的完备超曲面.利用活动标架的方法,得到此类超曲面的两个刚性定理.     

H~3(c)中常平均曲率曲面的稳定性

设M是3维双曲空间H~3(c)中常平均曲率曲面,本文通过估计M上共形度量的Gauss曲率,研究了其稳定性.     

双曲空间形式中具有常平均曲率的超曲面(英文)

本文研究了双曲空间形式H~(n+1)(—1)中具有常平均曲率及两个离散主曲率(其中一个主曲率是1-重)的完备连通可定向的n-维超曲面M~n.利用活动标架,得到如果M~n的基本形式的模长满足刚性条件(1.3),那么M~n同构双曲柱面.     

de Sitter空间中第二基本形式模长平方为常数的类空超曲面

设Mn是de Sitter空间S1n+1+1(c)中具有第二基本形式模长平方‖h‖2是常数的类空超曲面,利用极大值原理得到了Mn是全脐超曲面的三个充分条件.     

关于欧氏椭球面中平行和全脐超曲面的研究

我们给出了欧氏椭球面$Q^{n+1}(c,d)$中平行超曲面的完全分类,并且证明了$Q^{n+1}(c,d)$中的超曲面是全脐的当且仅当它是平行的.     

正定型超曲面上双曲闭特征的Maslov型指标的迭代公式

本文给出了R~(2n)中规范正定型超曲面上双曲闭特征的Maslov型指标的迭代公式.结果包含了凸超曲面和星形超曲面上已有的相应结论。     

n维双曲空间中给定Gauss映照的曲面的Weierstrass表示

将双曲上半空间Hn中的曲面视为Rn中的曲面,导出这两种共形浸入下平均曲率向量的关系;证明了这两种浸入下Gauss映照是一样的;给出Hn中给定Gauss映照的曲面的Weierstrass表示;证明了一个唯一性结果.     

n维双曲空间中给定Gauss映照的曲面的Weierstrass表示

将双曲上半空间Hn中的曲面视为Rn中的曲面,导出这两种共形浸入下平均曲率向量的关系;证明了这两种浸入下Gauss映照是一样的;给出Hn中给定Gauss映照的曲面的Weierstrass表示;证明了一个唯一性结果.     

Lorentz球面S_1~(n+1)中的Lorentz等参超曲面

对Riemann空间型中的等参超曲面有很多研究文献,至今已有近乎完美的结果.20世纪后期,对Lorentz空间R_1~(n+1)和Lorentz双曲空间H_1~(n+1)中的Lorentz等参超曲面前人已有完全分类.继续本文作者前面的工作,本文研究Lorentz球面S_1~(n+1)中的Lorentz等参超曲面,给出了所有种类的Lorentz等参超曲面的完全分类和解析表达式.     

逆向工程中基于NURBS的曲面重构

曲面重构是逆向工程中的关键技术.根据非均匀有理B样条曲面矩阵表达式,对于造型曲面上的(2m+1)×(2n+1)个型值数据点,推导了一个仅利用型值点数据反算二次非均匀有理B样条曲面控制顶点的算法.数值算例表明了该算法的有效性.     

关于单叶函数系数之—基本引理及其应用

<正> 设函数 f(z)=z+a_2Z~2+…在单位圆|z|<1上是正则的单叶的.这种函数的全体形成一族 S.S 中满足条件|f(z)|1上是单叶的,除开极点ζ=∞是正则的.这种函数的全体形成一族∑.∑中满足条件|F(ζ)|>R的函     

Analyse harmonique des formes différentielles sur l'espace hyperbolique réel I. Transformation de Poisson et fonctions sphériques

On one hand, we study the Poisson transforms of differential forms on real hyperbolic spaces and show that they are eigenfunctions for the corresponding algebra of invariant differential operators. On the other hand, we develop a matrix-valued generalization of the spherical function theory for Gelfand pairs. By combining these results we determine all spherical functions associated with the bundle of differential forms over real hyperbolic spaces and express them in terms of Jacobi functions.     

Constant mean curvature tori with spherical curvature lines in noneuclidean geometry

A previous result in Euclidean geometry [7] on H-tori with plane and spherical curvature lines is extended here to the two noneuclidean geometries. There result families of H-tori with only spherical curvature lines, which are explicitly representable by elliptic and theta functions (or ordinary integrals of elementary functions). Among the geometric properties, it is shown that the midpoints of the generating spheres vary on geodesics. The hyperbolic case is more similar to the Euclidean situation than the elliptic one. In elliptic geometry the constructed surfaces depend on one additional rational parameter and, as a limiting case, there are even countably many minimal tori of this type.     

Pointwise fourier inversion and related eigenfunction expansions

Necessary and sufficient conditions are found for the convergence at a pre-assigned point of the spherical partial sums (resp. integrals) of the Fourier series (resp. integral) in the class of piecewise smooth functions on Euclidean space. These results carry over unchanged to spherical harmonic expansions, Fourier transforms on hyperbolic space, and Dirichlet eigenfunction expansions with respect to the Laplace operator on a class of Riemannian manifolds. © 1994 John Wiley & Sons, Inc.     

鞅的(Φ_1,Φ_2)-型倒向极大不等式

设Φ_1,Φ_2是非负凸函数,证明了鞅的倒向极大算子不等式‖f‖Φ_2≤C‖f*‖Φ_1对于任意鞅f=(f_n)_n≥0成立的充分必要条件是Φ_2(?)Φ_1;鞅的极大算子均方算子的极大极小不等式‖M(f)‖Φ_2≤C_1‖m(f)‖Φ_1及‖m(f)‖Φ_2≤C_2‖M(f)‖Φ_1成立的充分必要条件是Φ_2(?)Φ_1,这里M(f)=max{f*,S(f)},m(f)=min{f*,S(f)}分别是极大算子、均方算子的极大极小函数.     

On the Schlafli differential formula based on edge lengths of tetrahedron in <Emphasis Type="Italic">H</Emphasis><Superscript>3</Superscript> and <Emphasis Type="Italic">S</Emphasis><Superscript>3</Superscript>

We obtain a new version of Schlafli differential formula based on edge lengths for the volume of a tetrahedron in hyperbolic and spherical 3-spaces, by using the edge matrix of a hyperbolic(or spherical) tetrahedron and its submatrix.      

具有亏值的亚纯函数的唯一性

改进了Ozawa的一个关于整函数的唯一性定理,得到了∞为亏值的亚纯函数唯一性的相应的几个结论.设亚纯函数f(z)与g(z)的级(或者下级)为有穷的非整数,满足.f=0→g=0,f=1g=1,f=∞9=∞,若∞为f(z)的Borel例外值,则f≡g.以及设f(z)与g(z)为C中非常数的亚纯函数,它们的级λ为有穷且非整数,再设它们满足f=0→g=0,f=1g=1,f=∞g=∞,若δ(∞,f)=1,f(z)为正规增长函数,则f≡g.     

SPECTRAL APPROXIMATION ORDERS OF MULTIDIMENSIONAL NONSTATIONARY BIORTHOGONAL SEMI-MULTIRESOLUTION ANALYSIS IN SOBOLEV SPACE

Subdivision algorithm （Stationary or Non-stationary） is one of the most active and exciting research topics in wavelet analysis and applied mathematical theory. In multidimensional non-stationary situation, its limit functions are both compactly supported and infinitely differentiable. Also, these limit functions can serve as the scaling functions to generate the multidimensional non-stationary orthogonal or biorthogonal semi-multiresolution analysis （Semi-MRAs）. The spectral approximation property of multidimensional non-stationary biorthogonal Semi-MRAs is considered in this paper. Based on nonstationary subdivision scheme and its limit scaling functions, it is shown that the multidimensional nonstationary biorthogonal Semi-MRAs have spectral approximation order r in Sobolev space H^s（R^d）, for all r ≥ s ≥ 0.     

On large orientation-reversing finite group-actions on 3-manifolds and equivariant Heegaard decompositions

We consider finite group-actions on closed, orientable and nonorientable 3-manifolds; such a finite group-action leaves invariant the two handlebodies of a Heegaard splitting of M of some genus g. The maximal possible order of a finite group-action of an orientable or nonorientable handlebody of genus $$g>1$$ is $$24(g-1)$$, and in the present paper we characterize the 3-manifolds M and groups G for which the maximal possible order $$|G| = 24(g-1)$$ is obtained, for some G-invariant Heegaard splitting of genus $$g>1$$. If M is reducible then it is obtained by doubling an action of maximal possible order $$24(g-1)$$ on a handlebody of genus g. If M is irreducible then it is a spherical, Euclidean or hyperbolic manifold obtained as a quotient of one of the three geometries by a normal subgroup of finite index of a Coxeter group associated to a Coxeter tetrahedron, or of a twisted version of such a Coxeter group.     

非欧空间中双基本图形的度量方程及其应用

本文提出了n维球面型空间和双曲空间中双基本图形的概念,建立了球面型空间与双曲空间中双基图形的度量方程,并给出度量方程的一些应用.