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报告主题: The normal closure of a bounding pair map in its mapping class group

报 告 人: 陈伟彦（清华大学丘成桐数学中心）

报告时间：2026年 6月22日（星期一）上午10:00-11:30

报告地点：清清文理楼3A02

邀 请 人: 杜晓明

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2026年6月15日

报告摘要：

The mapping class group of a surface consists of all self-homeomorphisms up to isotopy. It contains a mysterious subgroup, the Torelli group, which consists of mapping classes that act trivially on the homology of the surface. In the 1980s, Dennis Johnson proved a series of groundbreaking theorems about the Torelli group, one of which stated that it is normally generated by a single genus 1 bounding pair map. Extending Johnson's result, we give two descriptions of the normal subgroup generated by a genus n bounding pair map. We characterize this geometrically defined subgroup using the algebraic invariants of Chillingworth and Casson-Morita. This work is joint with Lei Chen and Justin Lanier.

报告人介绍：

陈伟彦博士毕业于芝加哥大学，师从Benson Farb，随后在明尼苏达大学做博士后，目前任职于清华大学丘成桐数学中心，从事拓扑以及其与代数几何、表示论、组合学的交叉处的研究。