报告题目：Hardy spaces associated with flag singular integrals

报告人：何少勇副教授，湖州师范大学

报告时间：2026年3月25日（周三）11:00-12:00

报告地点：20-306

报告摘要：In this talk, we will review the background of flag singular integrals as developed by Nagel, Ricci, and Stein in a series of papers in the late 1990s and early 2000s. These operators form a class of singular integral operators on Euclidean spaces that sits between the classical one‑parameter Calderón–Zygmund theory and the multi‑parameter theory of product kernels. Nagel, Ricci, and Stein established fundamental connections between product kernels and flag kernels, showing that on Euclidean space, product kernels can be expressed locally as finite sums of flag kernels. We further analyze the local behavior of both product and flag kernels and prove that local product kernels decompose into finite sums of local flag kernels. Finally, we will discuss Hardy spaces adapted to flag singular integrals, using a discrete Littlewood–Paley theory.

报告人简介：何少勇，湖州师范大学副教授。2021年于浙江师范大学获博士学位，曾获浙江省优秀博士学位论文奖。

邀请人：现代分析及其应用研究所