Non-differentiability of the Teichmuller cometric in infinite-dimensional Teichmuller spaces

The author shows the non-differentiability of the Teichmuller cometric for infinite-dimensional Teichmuller spaces. Let Y be a Riemann surface, the Teichm uller space of Y denoted by T(Y). For[X, f]∈T(Y), where [X. f] is an equivalent class of marked Riemann surfaces (X. f),

Geodesic uniqueness problem in infinite-dimensional Teichmuller spaces

LET[μ] be a point in a Teichmuller space T（Γ） and [μ]≠[0]. When T（Γ） is finite-di-mensional, the extremal Beltrami differential in [μ]is unique and the geodesic segment α:[tμ0] （0≤t≤1） is the unique geodesic segment joining [0] and [μ], where μ0 is the uniqueextremal Beltrami differential in [μ]. However, when T（Γ） is infinite-dimensional, [μ]

万有Teichmuller空间中测地线的不唯一性

本文主要讨论万有Ｔｅｉｃｈｍｔｉｌｌｅｒ空间中的测地线问题，并给出了一些测地线不唯一的判断准则．特别地，证明了如下定理：设ｆ是单位圆△到自身上的极值拟共形映射，μ是它的复特征，如果存在常数ｋ．＜｜｜μ｜｜＿∞，使集合｛ｚ∈△：｜μ（Ｚ）｜≤ｋ｝有内点，则在万有Ｔｅｉｃｈｍｕｌｌｅｒ空间中，原点［０］与［μ］之间存在无穷多条测地线．

Some Remarks on the Geodesics in Infinite Dimensional Teichmuller Spaces

Let B denote the set of those points p in an infinite dimensional Teichmiiller space such that a geodesic between the zero point and p is not unique. Some properties of the set B are given.

THE DISTANCE BETWEEN DIFFERENT COMPONENTS OF THE UNIVERSAL TEICHMULLER SPACE

The model of the universal Teichmuller union of infinite disconnected components. between different components is 0, and the every other component is 2. space by the derivatives of logarithm is the In this paper, it is proved that the distance distance from the center of a component to

基于任意拟圆的对数导数意义下区域的单叶性内径

研究了对数导数意义下区域的单叶性内径。以任意拟圆为基础,给出了区域对数导数单叶性内径下界的两个公式。此外,根据逼近区域的特征得到了区域的对数导数单叶性内径的另一个下界公式,并由此估计出正多边形的单叶性内径的上界。

拟对称映射的最大伸缩商与边界伸缩商

文献[1]在研究单位圆周■△上的拟对称自同胚的最大伸缩商与极值最大伸缩商之间的关系时,证明了:如果拟对称自同胚h的最大伸缩商Kq(h)不能在某个以开单位圆盘△为域、顶点在单位圆周■△上的拓扑四边形Q处达到,则一定有Kq(h)≤H(h)成立,其中H(h)为h的边界伸缩商.这一结论在文献[1]中起着重要作用,但证明比较烦琐.该文主要给出该结论一个简单的证明,并且利用这一结论研究拟对称自同胚的最大伸缩商何时可以在某个拓扑四边形上达到.

一杯咖啡背后的拓扑

日常喝咖啡,可以使我们感悟到奇妙的拓扑学原理。我们均匀搅拌咖啡,咖啡静止后会有一个分子回到初始位置,这是经典的布劳威尔不动点定理,我们用代数拓扑的方法加以证明;咖啡拉花经过搅拌后变得愈发复杂,但是咖啡拉花的抽象模式保持不变,这反映了曲面同胚映射的动力学特性,可以用泰希米勒空间和布劳威尔不动点定理加以证明。

万有Teichmller空间的某些性质

本文讨论了以单位国内共形映射的对数导数为模型的万有Teichm(?)ller空间的拓扑性质,用较I. V. Zhuravlev简单的方法证明这种万有Teichm(?)ller空间的不连通性并得到更深入的结果,证明其每个连通分支是可缩的。

拟对称映射的最大伸缩商

万有Teichmller空间的研究中有三个非常重要的量:单位圆到自身的拟对称映射的极值最大伸缩商,拟对称最大伸缩商以及边界伸缩商.对于拟对称映射的最大伸缩商,有一个平行于一般极值伸缩商与边界伸缩商充要条件的问题,证明了对于一些特殊的拟对称映射,问题的答案是否定的.

Isomorphisms of fiber spaces over Teichmüller spaces

We will be mainly concerned with some important fiber spaces over Teichmuller spaces, including the Bers fiber space and Teichmuller curve, establishing an isomorphism theorem between 'punctured' Teichmuller curves and determining the biholomorphic isomorphisms of these fiber spaces.

Amenability, Poincare series operator and Teichmuller distance

Any covering Y→X of a hyperbolic Riemann surface X determines an inclusion of Teichmuller spaces T(X)→T(Y). This map is shown to be an isometry for the Teichmuller metric iff the covering is amenable, and contracting iff for any [μ]εT(X), where is the Poincare series operator. Furthermore the inclusion is not a uniform contraction on T(X).

Kobayashi’s and Teichmuller’s Metrics and Bers Complex Manifold Structure on Circle Diffeomorphisms

Given a modulus of continuity ω,we consider the Teichmuller space TC1+ω as the space of all orientation-preserving circle diffeomorphisms whose derivatives are ω-continuous functions modulo the space of Mobius transformations preserving the unit disk.We study several distortion properties for diffeomorphisms and quasisymmetric homeomorphisms.Using these distortion properties,we give the Bers complex manifold structure on the Teichm(u| ")ller space TC^1+H as the union of over all0 <α≤1,which turns out to be the largest space in the Teichmuller space of C1 orientation-preserving circle diffeomorphisms on which we can assign such a structure.Furthermore,we prove that with the Bers complex manifold structure on TC^1+H ,Kobayashi’s metric and Teichmuller’s metric coincide.

Teichmuller空间的星形结构问题

对于任一保持单位圆盘Δ及其外部Δ的Ｆｕｃｈｓ群Γ，利用Ｂｅｒｓ嵌入，Ｔｅｉｃｈｍｕｌｌｅｒ空间Ｔ（Γ）可看成是Δ上Γ的有界全纯二次微分Ｂ（Δ，Γ）中的一个有界区域，本文的目的是讨论Ｔｅｉｃｈｍｕｌｌｅｒ空间Ｔ（Γ）的星形问题。特别地，我们证明了：当Γ是第二类Ｆｕｃｈｓ群时，Ｔ（Γ）不是星形的．

Teichmuller空间中的极值长度函数

利用极值长度函数，研究了Ｔｅｉｃｈｍｕｌｌｅｒ空间中的度量问题及多次调和性，得到了极值长度在地震形变下的变化规律．

万有Teichmüller空间不同模型中的测地线唯一性

研究万有Teichmülle空间不同模型中的测地线的唯一性问题。证明了在万有Teichmülle空间中存在两个点,它们之间的测地线唯一,但在万有Teichmülle空间的Schwarz导数与Pre-Schwarz导数模型中,这两个点所对应的点之间的测地线不唯一。

平面区域上的极值问题

文章把双曲黎曼曲面上关于极值拟共形映射的一些结果推广到了平面区域Ω=C^-E上,其中E<^C为闭集,0,1,∞∈E。

On Holomorphic Sections in Teichmiiller Spaces

It is proved that, for any elementary torsion free Fuchsian group F, the natural projection from the Teichmiiller curve V（F） to the Teichmiiller space T（F） has no holomorphic section.

Geometric aspects of the moduli space of Riemann surfaces

We describe some recent progress in the study of moduli space of Riemann surfaces in this survey paper. New complete Kahler metrics were introduced on the moduli space and Teichmuller space. Their curvature properties and asymptotic behavior were studied in details. These natural metrics served as bridges to connect all the known canonical metrics, especially the Kahler-Einstein metric. We showed that all the known complete metrics on the moduli space are equivalent and have Poincare type growth. Furthermore,the Kahler-Einstein metric has strongly bounded geometry. This also implied that the logarithm cotangent bundle of the moduli space is stable in the sense of Mumford.

On Nonuniqueness of Geodesics and Geodesic Disks in the Universal Asymptotic Teichmüller Space

Abstract The non-uniqueness on geodesics and geodesic disks in the universal asymptotic Teichmfiller space AT（D） are studied in this paper. It is proved that if # is asymptotically extremal in [[#]] with h （μ） 〈 h＊ （μ） for some point ζ∈D, then there exist infinitely many geodesic segments joining [[0]] and [[μ]], and infinitely many holomorphic geodesic disks containing [[0]] and [μ]] in AT（D）.