报告人： 杨大春，北京师范大学

题目: Ball Banach Function Spaces Meet BBM, BVY, and BSVY Formulae

摘要: The concept of ball quasi-Banach function (BQBF) spaces was introduced in 2017by Y. Sawano, K.-P. Ho, D. Yang, and S. Yang. It is well known that some well-known function spaces, such as Morrey spaces, weighted Lebesgue spaces, mixed-norm Lebesgue spaces, and Orlicz-slice spaces, are ball quasi-Banach function spaces,but not quasi-Banach function spaces. In this talk, we will first recall the celebrated (BBM) formulae of J. Bourgain, H. Brezis, and P. Mironescu and the recent surprising (BVY and BSVY) formulae of H. Brezis, A. Seeger, J. Van Schaftingen, and P.-L. Yung. Then we will introduce some recent extensions of these formulae to Sobolev spaces associated with ball Banach function spaces. In particular, we will introduce some methods on how to overcome the difficulties caused by the deficiency of the translation invariance, the rotation invariance, and the explicit expression of the quasi-norm of BQBF spaces under consideration.

时间：4月30日（周二）上午9:00-10:30

腾讯会议 ID： 643-129-839