报告题目：Totally ramified rational functions

报告人：Jun Hu  （City University of New York）

报告时间：2025.6.26 上午10：00-11：00

报告地点：数学楼301室

报告内容简介： A rational functuon f on the Riemann sphere is said to be totally ramified if every preimage of each critical value is a critical point. I will first explain how it appeared from the classification of finite Kleinian groups, which actually are regularly ramified. Then I will explain why non-regularly ramified rational functions exist if and only if the degrees are at least seven. Thirdly, I will explain why it is importance to know the existence of such a function for any degree at least two. Finally, I explain how often for non-regularly ramified ones to appear. Some of the results are joint works with Weiwei Cui or Yinqing Xiao. This talk is accessible to first-year undergrduate students.

报告人简介：胡骏教授，1989年被陈省身留美项目选送去美攻读博士学位，师从Dennis Sullivan教授。主要的研究领域是低维动力系统和黎曼曲面上不同复结构组成的 Teichmuller空间的不同描述。发表论文近50篇。美国数学会和美国自然科学基金会设立的数学博士后fellowship获得者。曾是加州伯克莱大学数学研究所、法国高等学术研究所、马里兰大学帕克分校、新泽西州立罗格斯大学纽瓦克分校、纽约州立大学石溪分校和上海纽约大学的访问学者或访问教授。