During the period of August 12-23, 2019, Professor Maosheng Xiong of the Hong Kong University of Science and Technology was invited to visit our college. During his visit, he gave an academic report entitled "Constructing differentially 4-uniform permutations over GF(2^(2m)) from quadratic APN permutations over GF(2^(2m+1))" on August 14 and an academic report entitled "From weight enumerators to zeta functions" on August 18, respectively.

In the reports, Xiong introduced permutation polynomials, APN functions and zeta functions in detail, and had a deep communication and discussion with the teachers and students who participated in the reports, which made us gain a lot.

Maosheng Xiong, a professor at Hong Kong University of Science and Technology, has made many important results in the fields of number theory, coding and cryptography. He has presided over a number of projects of the Hong Kong Research Grant Authority and presided over a joint project between the National Science Foundation of China and the Hong Kong Research Grant Council. He has published more than 40 papers in international journals such as IEEE Transactions on Information Theory, Finite Fields and Their Applications, Designs, Codes and Cryptography, etc.