Title： Some Characterizations of Smoothness Function Spaces

Speaker: Wen YUAN (北京师范大学)

Time: 14:00-15:00 26/04/2023      立德楼315

Abstract:  Function spaces with certain smoothness, such as Sobolev spaces, Lipschitz spaces, Besov spaces and Triebel-Lizorkin spaces, are widely used in different areas of mathematics. In this talk, we first recall a series of classical smoothness function spaces,

as well as various tools to describe smoothness of functions  or distributions. Then we introduce two progress on the characterization of Sobolev type spaces: the first one is characterizations of Sobolev type spaces via differeces of ball averages, and the other one is characterizations of the first-order Sobolev type spaces via the Gagliardo seminorms.