4月12日下午，应学院邀请，印度Harish-Chandra研究所Chakraborty教授、Hoque博士在我院学术交流厅分别进行了题为“Class numbers of quadratic fields”和“Pell-type equations and class groups of cyclotomic field”的精彩报告，报告由张天平副教授主持。学院青年教师高玉彬、刘杭、王章结，以及相关专业数十名研究生聆听了此次报告。报告还吸引了兄弟院校相关专业的数位教师参与。

在报告中，Chakraborty教授讨论了一些二次域的类数。基于与Hoque、Kishi和Pandey共同完成的一些工作，Chakraborty教授从定性和定量两方面分别讨论了实二次域和虚二次域上类数的整除性，并介绍了虚二次域上的3阶理想类群的一些最新进展。

基于与Chakraborty共同完成的一些工作，Hoque博士讨论了一些Pell类型方程的可解性。然后，应用已知的结果来寻找具有非平凡类群的分圆域的集合。最后，构造了一类具有三阶元素的类群的分圆域的集合。

报告结束后，Chakraborty教授与Hoque教授还同与会师生进行了深入的互动交流。

** Chakraborty教授简介：**

Dr. Chakraborty earned his Ph.D. in Mathematics in 1998 from Harish-Chandra Research Institute, Allahabad, India under the supervision of Prof. B Ramakrishnan. In 1997, he joined The Institute of Mathematical Sciences, Chennai, India as a post-doctoral fellow. After that he joined Queen’s University, Canada as a post-doctoral fellow. Dr. Chakraborty came back to India in 2001, and joined Harish-Chandra Research Institute as an assistant professor. Currently, he is a professor at Harish-Chandra Research Institute, Allahabad, India. He visited University of Paris VI, Paris, University of Paris VII, Paris, Tokyo Metropolitan University, Japan, Kinki University, Japan, Kyoto Sangyo University, Japan, Waseda University, Japan, Universitá Roma Tre, Italy, the University of Hong Kong, Hong Kong, Northwest University, China, Shandong University, China, Shangluo University, China, Mahidol University, Thailand, Mandalaya University, Myanmar, Eötvös Loránd University, Budapest, and many more.

The broad area of research of Dr. Chakraborty lies in Algebraic Number Theory as well as in Analytic Number Theory. In particular, his research areas include: ideal class groups of algebraic numbers fields; Diophantine equations; automorphic forms; arithmetic functions; elliptic curves, cryptography and special functions. He has published more than 50 research articles in reputed journals. He has also published 2 books in number theory. He has produced 5 Ph.D. students under his guidance. He is also serving as an editorial member of some reputed journals.

** Hoque博士简介：**

Dr. Hoque earned his M.Sc. degree in Mathematics from Gauhati University, Guwahati, India, in 2008 and then he did his M. Tech. degree from Tezpur University, Tezpur India in 2011. After that he joined Regional Institute of Science and Technology, Meghalaya, India in 2011 as an Assistant Professor. He joined Ph.D. programme in 2012 at Gauhati University, Guwahati, India under the supervision of Prof. Helen K. Saikia and finished his Ph. D. in 2015. He also worked at Gauhati University Institute of Science and Technology, Guwahati, India during the period October, 2012–February, 2016 as an assistant professor. He has joined Harish-Chandra Research Institute, Allahabad, India on March, 2016. He visited the University of Hong Kong, Hong Kong, Northwest University, China, Shangluo University, China, Mahidol University, Thailand, Mandalaya University, Myanmar etc.

The broad research area of Dr. Hoque lies in Algebraic Number Theory as well as in Analytic Number Theory. In particular, his research areas include: ideal class groups of algebraic numbers fields; Diophantine equations; arithmetic functions; elliptic curves and zeta functions. The title of his Ph. D. thesis is “A study on the class numbers of quadratic and cyclotomic fields”. He has published more than 20 research articles in well-known journals.