Convex hull of set in thick part of Teichmller space

Let X be a non-elementary Riemann surface of type(g,n),where g is the number of genus and n is the number of punctures with 3g-3+n1.Let T(X)be the Teichmller space of X.By constructing a certain subset E of T(X),we show that the convex hull of E with respect to the Teichmller metric,the Carathodory metric and the Weil-Petersson metric is not in any thick part of the Teichmler space,respectively.This implies that convex hulls of thick part of Teichmller space with respect to these metrics are not always in thick part of Teichmller space,as well as the facts that thick part of Teichmller space is not always convex with respect to these metrics.     

万有Teichmüller空间对数导数嵌入模型的一些性质

在对数导数意义下,万有Teichmüller空间T_1可表示为无穷多个互不相交的连通分支的并集T_1={■ L_θ}∪L,研究了该模型分支边界的几何性质,证明了L与L_θ的边界存在无穷多个公共点,同时还解决了关于一个分支中的点到另一分支中心距离上确界的公开问题．     

A BINARY INFINITESIMAL FORM OF TEICHMLLER METRIC AND ANGLES IN AN ASYMPTOTIC TEICHMLLER SPACE

The geometry of Teichmller metric in an asymptotic Teichmller space is studied in this article. First, a binary infinitesimal form of Teichmller metric on AT(X) is proved.Then, the notion of angles between two geodesic curves in the asymptotic Teichmller space AT(X) is introduced. The existence of such angles is proved and the explicit formula is obtained. As an application, a sufficient condition for non-uniqueness geodesics in AT(X) is obtained.     

万有Teichmüller空间对数导数嵌人模型的一些性质

在对数导数意义下,万有Teichmüller空间T1可表示为无穷多个互不相交的连通分支的并集T1={∪θ∈[0,2)Lθ}∪L,研究了该模型分支边界的几何性质,证明了L与Lθ的边界存在无穷多个公共点,同时还解决了关于一个分支中的点到另一分支中心距离上确界的公开问题.     

关于Teichmüller极值的等价性

分别记T(Δ)与B(Δ)为单位圆盘Δ上的Teichmüller空间与无限小Teichmüller空间.证明了|v|B(Δ)是无限小Strebel点并不能说明|v|T(Δ)是一个Strebel点以及|v|T(Δ)是Strebel点并不能说明|v|B(Δ)是一个无限小Strebel点.作为这个结论的应用,解决了姚国武提出的问题.     

渐近Teichmüller空间的不唯一性

设AT(△)是单位圆盘△上所有渐近Teichmüller等价类[[μ]]或[[f~μ]]构成的渐近Teichmüller空间.本文证明了对AT(△)内的任意渐近极值的f~μ,总存在一个[[f~μ]]内的渐近极值映射g~v,使边界伸缩商h~*(μ_(fog)~(-1)(g(z)))≠0.同时也获得了AT(△)在基点处的切空间上的类似结果.     

星形函数与万有Teichmüller空间的一个模型

得到了,当f(z)∈S*[A,B]且-1相似文献   

Hausdorff dimension of quasi-cirles of polygonal mappings and its applications

We show that the Hausdorff dimension of quasi-circles of polygonal mappings is one.Furthermore,we apply this result to the theory of extremal quasiconformal mappings.Let [μ] be a point in the universal Teichmller space such that the Hausdorff dimension of fμ(Δ) is bigger than one.We show that for every kn∈(0,1) and polygonal differentials ψn,n=1,2,...,the sequence {[kn ψn/|ψn|]} cannot converge to [μ] under the Teichmer metric.     

黎曼面局部Torelli定理的新证明

利用亏格为g(g≥2)的闭曲面的Teichm(u|¨)ller空间上的Kuranishi坐标和闭黎曼面上全纯1-形式的显式形变公式,我们给出从Teichm(u|¨)ller空间到Siegel上半空间的周期映射的显示表达,从而得到了闭黎曼面的两个局部Torelli定理的新证明.     

Inequalities on the inner radius of univalency and the norm of pre-Schwarzian derivative

In this paper, we get a lower bound of inner radius of univalency of Schwarzian derivative by means of the norm of pre-Schwarzian derivative. Furthermore, we apply the theory of Universal Teichmuller Space to explain its geometric meaning which shows the relationship between the inner radius in Universal Teichmuller Space embedded by Schwarzian derivative and the norm defined in Universal Teichmuller Space embedded by pre-Schwarzian derivative.     

多复变数的Schwarz导数(Ⅴ)

本文从Thurston的观点出发,用二阶逼近来定义与讨论矩阵空间C~(m×n)（m≤n）中的域上全纯映照的Schwarz导数及高阶Schwarz导数,证明：如果它们存在的话,那么它们是在R_I（m,n）的紧对偶空间CG（m,n）的全纯自同构群下的相似不变量．并证明：这样得到的Schwarz导数与前几文［1－4］中由Ahlfors的观点得到的Schwarz导数是相一致的．此外,还应用这种观点定义与讨论了C~N中的域上全纯映照的Schwarz导数．     

极值Beltrami系数的Hamilton序列

考虑了Strebel点与Hamilton序列之间的关系.这个问题是Gardiner F.P.最早研究的(见[Approximation of infinite-dimensional Tcichmiiller spaces,Trans.Amer.Math.Soc.,1984,282(1):367-383]).在无限小Teichmiiller空间中,证明了范金华在[On infinitesimal Teichmüller space,Bull.Austral Math.Soc.,2008,78:293-300]中得到的使{φ_n}成为Hamilton序列的充分条件不是必要的.     

万有Teichmuller空间各分支边界点的一些几何性质

在对数导数意义下,万有Teichmuller空间T1可表示为无穷多个互不相交的连通分支的并集.本文研究了该模型各分支的几何性质,给出了为e-iθ/（1-e-iθz）为L和Le的公共边界点,且在‖·‖1的意义下,证明了L,L0,Lθ两两公共边界点之间的距离均为2.     

Integrable Teichmüller spaces

A new kind of subspaces of the universal Teichmüller space is introduced. Some characterizations of the subspaces are given in terms of univalent functions, Beltrami coefficients and quasisymmetric homeomorphisms of the boundary of the unit disc.     

The Schwarzian derivative in several complex variables (III)

In the point view of Lie group, the cross ratio and Schwarzian derivative in Cⁿ are defined and discussed, especially the Schwarzian derivative of holomorphic mappings on the domains in matrix space C^{m x n} is defined and discussed. It is proved that it is invariant up to similarity under the group of holomorphic automorphism of the Grassmann manifold CG(m, n). And it is also proved that the Schwarzian derivative equals zero if and only if the mapping is liaearly fractional. Project supported by the National Natural Science Foundation of China.     

On the outradius of the teichmüller space

Let Γ be a fuchsian group which preserves the unit disc Δ and hence also its complement Δ^* in the Riemann sphere . The Bers embedding represents the Teichm=:uller space T(Γ) of Γ in the space (B (Δ^*, Γ) of bounded quadratic differentials for Γ in Δ^*. Then, T(Γ) is included in the closed ball centred at the origin of radius 6 inB(Δ^*, Γ) with respect to the norm employed in a paper by Nehari [The Schwarzian derivative and Schlicht functions; Bull. Amer. Math. Soc. 55 (1949), 545–551]. In other words the outradiuso(Γ) ofT(Γ) is not greater than 6. The purpose of this paper is to give a complete characterization of a fuchsian group Γ for which the outradiuso(Γ) ofT(Γ) attains this extremal value 6. The main theorem is: Let Γ be a fuchsian group preserving Δ^*. Then the outradiuso(Γ) of the Teichmüller spaceT(Γ) equals 6 if and only if for any positive numberd, either (i) there exists a hyperbolic disc of radiusd precisely invariant under the trivial subgroup, or (ii) there exists the collar of widthd about the axis of a hyperbolic element of Γ. Dedicated to Professor K?taro Oikawa on his 60th birthday     

求解Riesz空间分数阶扩散方程的一种新的数值方法

本文利用Diethelm方法构造了一种逼近Riesz空间分数阶导数的O（△x^3-α）格式,其中1 < α < 2,△x是空间步长.进一步对一阶时间导数采用Crank-Nicolson方法离散,得到了求解Riesz空间分数阶扩散方程的一种新的有限差分格式,并用矩阵方法证明了稳定性和收敛性,其误差估计为O（△t²+△x^3-α）,其中△t为时间步长.最后,数值算例验证了差分格式的正确性和有效性.     

二阶P—Laplacian问题三个正解的存在性

本文要讨论了二阶P—Laplaci!an方程边值问题{△（φ（Au（t-1）））＋a（t），（t，u（t））=0，t∈N[1，T＋1]；△u（O）=0，u（T＋2）=0三个正解的存在性。通过利用一个三解不动点定理，证明了当，（t，x）在满足较弱条件时该方程至少三个正解的存在性。     

Schwarzian 导数, 几何条件和QK 空间

设ψ : D → Ω 是一个单叶函数, 利用Schwarzian 导数, 本文获得了log ψ′ 属于Q_K 空间的一个充要条件. 此外, 本文运用了一个几何条件来刻画Q_K 空间.