由哈尔滨工业大学国际合作部“国际学者云课堂”系列活动组织，应数学学院汪贤超副教授的邀请，香港城市大学数学系刘宏宇教授将于近日在数学学院做系列学术报告。以下是报告信息，欢迎感兴趣的广大师生参加。

报告时间：2022年5月29日(周日)，8:30-11:30

报告题目一：Mathematical theory of visibility and invisibility

报告摘要：This is the first one of a series of talks on the mathematical theory of visibility and invisibility.I shall present a bird view of the mathematical study of inverse problems including the two faces of visibility and invisibility.

报告题目二：Overdetermined PDEs and Schiffer’s problem in inverse scattering theory

报告摘要：Schiffer’s problem asks whether one can determine the shape of an obstacle by a single far-field measurement. It is a well know and longstanding geometric inverse problem in scattering theory. I shall describe the research progress of our group as well as proffer several conjectures.

报告时间：2022年5月30日(周一)， 14:00-17:00

报告题目三：Mathematical theory of a class of inverse problems with unknown sources and mediums

报告摘要：We are mainly concerned with a class of inverse problems where one intends to simultaneously recover certain unknown sources and mediums by using passive or active measurements. This type of inverse problems arises in a variety of cutting-edge applications including photo-acoustic tomography, MAD (magnetic anomaly detection) technology, earthquake precursor detection and cosmological exploration. In this talk, I shall discuss the mathematical progress of our study including the modeling, unique identifiability and numerical reconstruction results.

报告题目四：Mathematical theory of invisibility cloaking and metamaterials

报告摘要：Invisibility is the other face of inverse problem where one intends to hide the information of a target object from being detected with respect to certain probing means. In this talk, I shall discuss our mathematical understanding of two cloaking approaches, one by transformation medium coating and the other one by anomalous localized resonances, both using metamaterials.

报告时间：2022年5月31日(周二)， 14:00-17:00

报告题目五：Spectral geometry of transmission resonance and applications

报告摘要：Transmission eigenvalue problems are a type of non-elliptic, non-self-adjoint and nonlinear (in a certain sense) spectral problems that arise in scattering theory when transparency/invisibility occurs. We discover that transmission eigenfunctions possess rich geometric structures. I shall discuss those intriguing geometric patterns as well as the associated applications in inverse problems, which show the reconciliation of visibility and invisibility.

报告题目六：Inverse scattering, bionic learning and AIs

报告摘要：In this talk, I shall discuss the interplay among inverse scattering techniques, bionic learning and artificial intelligences and report several interesting discoveries by our research group.

报告形式：腾讯会议，会议号：578 7181 1431

报告人简介：刘宏宇，香港城市大学数学系教授，国家级高层次人才，福建省闽江学者讲座教授。研究领域为应用数学和计算数学，包括反问题，波成像，数学物理方程，超材料的数学理论，散射理论和谱几何。近年来也探讨反散射与仿生学习及人工智能的交叉和结合。