（一）

报告人：徐国义博士

报告题目： Three Circles Theorems for harmonic functions

报告摘要： I will present my recent work on harmonic functions over manifolds with non-negative Ricci curvature. I will try to tell the main line of the story about the harmonic functions on manifolds since Yau's work, and explain the intuitive idea behind the proof of our main results （including the existence of nontrivial harmonic functions of polynomial growth, the uniform bound of the frequency of those harmonic functions）. And suitable technical stuff will presented, but elementary differential geometry and PDE knowledge is enough for understanding most part of the talk.

时间：5月29日下午4:00-5:00

地点：E402

报告人简历：2010年获得美国明尼苏达州立大学博士学位，2010年至2013年在加州大学Irvine分校做博士后研究，2013年七月至今在清华大学数学系担任助理教授。目前主持国家基金一项。

（二）

报告人：黄显涛博士

报告题目：Path-connectedness of the moduli space of metrics with positive isotropic curvature on four-manifolds

报告摘要：sotropic curvature was introduced by Micallef and Moore, this curvature condition appears naturally in the second variation formula of energy of surfaces, and it also plays a key role in the proof of the famous 1/4-sphere theorem. The classification of manifolds with positive isotropic curvature is also an interesting problem. By studying Ricci flow with surgery on four dimensional orbifolds with isolated singularities, Chen, Tang and Zhu gave a complete classification of compact four-manifolds admitting metrics with positive isotropic curvature. Based on Chen, Tang and Zhu’s work, we begin to study the moduli space of metrics with positive isotropic curvature on four-manifolds. In this talk, I will introduce my joint work with Prof. Bing-long Chen, which studying the Path-connectedness of the moduli space of metrics with positive isotropic curvature on certain four-manifolds.

 时间：5月29日下午5:00-6:00

 地点：E402

 报告人简历：2014年获得中山大学博士学位，2014年7月至今在清华大学丘成桐数学中心从事博士后研究。