2010-9-7 Tuesday 首页简介学术活动新闻图书馆下载ENGLISH


FROM 2010-6-1 TO 2010-12-31
Organizer: Guizhen Cui, Yunping Jiang and Yuefei Wang

●INTRODUCTION

晨兴数学中心“复动力系统”项目

 

l Participants

沈维孝 (NationalUniversity of Singapore)

TAN Lei (Universite de Angers)

Walter Bergweiler (Kiel University, Germany)

Laurent Bartholdi (Universität zu Göttingen)

Michel Zinsmeister (Universite de Orleans)

Arnaud Cheritat (Institut de Mathematiques deToulouse)

Sebastien Godillon (Universite de Cergy-Pontoise

伍胜健(北京大学)

乔建永(中国矿业大学)

  毅(北京航空航天大学)

张广远(清华大学)

方丽萍(北京理工大学)

尹永成(复旦大学)

邱维元(复旦大学)

沈玉良(苏州大学)

张高飞(南京大学)

刘劲松 (数学院)

  涛(华东师范大学)

范金华(南京理工大学)

彭文娟(数学院)

  羽(数学院)

李保奎(北京理工大学)

高君杨(中国矿业大学)

  丹(数学院)

廖良文(南京大学)

 

lProgram

A.    Lectures

1. Title: Dynamics of transcendental entire functions

Speaker: Walter Bergweiler

Time: Wednesday (August 25-November 17,2010) 2:30 pm

Venue: MCM 410

 

2. Title: Algebraic invariants ofholomorphic dynamics

Speaker: Laurent Bartholdi

Time: Tuesday (September 7-December 21,2010) 2:30 pm

Venue: MCM 705

 

3. Title: Random and deterministic growthprocesses

Speaker: Michel Zinsmeister

Time: Thursday (September 15-October 15)2:30 pm

Venue: MCM 410

B.      Seminar

1. Title: One-dimensional Dynamics (I)

Speaker: Weixiao Shen (National University of Singapore)

Time: June 24 (Thursday) 2:30 pm

Venue: MCM 410

 

2. Title: One-dimensional Dynamics (II)

Speaker: Weixiao Shen  (National University of Singapore)

Time: June 29 (Tuesday) 2:30 pm

Venue: MCM 705

 

3. Title: Teichmuller space and geodesic currents

Speaker: Xiaobo Liu(刘晓波)(AMSS)

Time: July 1 (Thursday) 2:30 pm

Venue: MCM 410

Abstract:为了利用双曲几何研究拓扑曲面上曲线的同伦类,F.Bonahon 引进了 geodesic currents, 即测地线空间上的测度。Teichmuller 空间及其 Thurston 紧化可以实现为此测度空间中的双曲面模型。

 

4. Title: The best bound of the area-length ratio in Ahlfors' covering surface theory

Speaker: Guangyuan Zhang (Tsinghua)

Time: July 8 (Thursday) 2:30 pm

Venue: MCM 410

Abstract:Let $D$ be a closed disk in the complex plane and let $S$ be the unit Riemann sphere. A basic consequence of Ahlfors' theory of covering surfaces is that there exists an absolute constant $h$ such that for any nonconstant holomorphic mapping $f$ from $D$ into $S$, if $f$ does not take the three values $0$, $1$ and infinity, then $A/L < h$, where $A$ is the area of the image of $D$ and $L$ is the length of the image of the boundary of $D$, both counting multiplicities. We will introduce our recent work that give the precise bound of the ratio $A/L$.

 

5. Title: No invariant line fields on escaping set of a sine family

Speaker: Tao CHEN (CUNY)

Time: July 15 (Thursday) 2:30 pm

Venue: MCM 410

 

6. Title: On the convergence of Thurston's algorithm for hyperbolic exponential maps

Speaker: 张高飞 (Nanjing Univ.)

Time: July 22 (Thursday) 2:30 pm

Venue: MCM 410

 

7. Title: Combinatorial rigidity for unicritical maps

Speaker: Wenjuan PENG (AMSS)

Time: July 29 (Thursday) 2:30 pm

Venue: MCM 410

 

8. Title: Holomorphic motions, homotopy, and homologous

Speaker: 蒋云平 (CUNY)

Time: August 5 (Thursday) 2:30 pm

Venue: MCM 410

 

9. Title: Density of hyperbolic rational maps

Speaker: Yu ZHAI (AMSS)

Time: August 12 (Thursday) 2:30 pm

Venue: MCM 410

 

10. Title: Complex manifold structure on a bundle of universal Teichmuller space

Speaker: Zhe WANG (CUNY)

Time: August 19 (Thursday) 2:30 pm

Venue: MCM 410

 

C.      Students Seminar

  • July 6, 高延 Iterated monodromy groups
  • July 13, 褚海丰 Post-crtically finite topological polynomials
  • July 20, 周恒宇 Exponential Thurston maps and limits of quadratic differentials (I)
  • July 21, 凡石磊 (AMSS) , Twisted rabbits
  • July 27, 周恒宇 Exponential Thurston maps and limits of quadratic differentials (II)
  • July 28, 陈涛 (CUNY), Canonical Thurston obstruction of subhyperbolic branched covering
  • August 3, 张高飞 (Nanjing Univ.), An introduction to Siegel disks
  • August 4, 胡云春 (CUNY), Martingales and almost complex structure
  • August 10, 陈涛 (CUNY), Expanding Thurston maps
  • August 11, 王哲 (CUNY), Tracking a point on a Riemann surface
  • August 17, 唐树安 (Peking Univ.), On Lunar equations

lAbstracts of the Lectures

1. Title: Dynamics of transcendental entire functions

Speaker: Walter Bergweiler

 

Complex dynamics is concerned with the behavior ofanalytic functions under iteration. The iteration theory of rational functionsbegan with long memoirs by Fatou and Julia in 1918-1920. In the 1980s the areabecame again an area of very active research. This is partially due to thebeautiful computer graphics related to it, but - more importantly - there werealso new and powerful mathematical methods introduced to the subject bySullivan, Douady and Hubbard, and others.

 

The iteration of transcendental entire functions wasfirst studied by Fatou in 1926, but in recent years there has been majorinterest in the subject again. In part the theory runs parallel to that ofrational functions, but there are also significant differences. For example,while a theorem of Sullivan says that rational functions do not have wanderingdomains, such domains may exist for transcendental entire functions. Besides theJulia set, a major role in transcendental dynamics is played by the escapingset consisting of those points which tend to infinity under iteration. By atheorem of Eremenko, the Julia set is the boundary of the escaping set.

 

The purpose of this lectures is to give anintroduction to complex dynamics. While the focus will be on the dynamics oftranscendental entire functions, we do not assume familiarity with the dynamicsof rational functions. Some mathematical tools that are particularly helpful inthe iteration theory of transcendental entire functions (e.g. the Ahlforstheory of covering surfaces or Wiman-Valiron theory) will also be reviewed.

 

2. Title:  Algebraic invariants of holomorphicdynamics

Speaker: Laurent Bartholdi

 

Self-similar (or fractal) objects abound ingeometry, but their impact on algebra is relatively new. Groups, associativealgebras, and Lie algebras are called self-similar if they are equippedwith a biset (respectively bimodule), namely a set (resp. module) withcommuting left and right actions, which is free qua right set (resp.module). Important examples include the infinite torsion groups, and groups ofexponential growth, by Grigorchuk inter alia.

 

A dynamical system may be conveniently encoded as aself-similar group; this yields an extremely potent algebraic invariant of thatdynamical system, and a link between dynamics and algebra.

 

The purpose of this program is to study the linksbetween group theory and holomorphic dynamics, with particular focus onalgebraization of Thurston's algorithm.

 

3. Title: Random and deterministic growth processes

Speaker: Michel Zinsmeister

 

In 1923, in order to prove Bieberbach conjecture forunivalent functions for n=3, Lowner has shown how one can associate to acontinuous function (called the driving function) from the positive realhalf-line to the circle an increasing family of compact sets in the plane. In1999, Oded Schramm revived this theory by showing that if we choose as drivingfunction a Brownian motion then one obtains sets that describe the scalinglimit of many interfaces coming from statistical mechanics such as the onesoccurring in percolation theory. This fundamental discovery revived the studyof deterministic Lowner processes as well as growth processes in general. Thereis a random growth process initiated by physicists called DLA which is still acomplete mystery from the mathematical point of view and it is hoped thatLowner theory could yield some light on it.

 

The purpose of this program is to give a detailedaccount of general Lowner theory followed by its applications. Of course theSLE processes of Schramm will be discussed in details. Hele-Shaw flows and theHastings-Levitov model of DLA will also be discussed, the emphasis being put onthe connection with Lowner theory.

 


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