报告题目：Around the commutators of quadratic operators

　　报告人：张远航教授

　　报告时间：2023.12.7 15：30-16：30

　　报告地点：数学与统计学院 104报告厅

　　报告人简介：张远航，吉林大学数学学院教授，博士生导师，主要研究兴趣包括：C*-代数分类理论及应用、套代数的可逆元群连通性问题、有界线性算子的交换子、矩阵代数的非对角块。已在JFA、JNCG、JOT、Studia Math.、PAMS、IEOT及中国科学(中、英文版)等杂志上发表(含已接受)学术论文10多篇。现主持国家自然科学基金面上基金一项。

　　报告内容简介：
　　We will study the norm-closure of the set $\mathfrak{C}_{\mathfrak{E}}$ of bounded linear operators acting on a complex, separable Hilbert space $\mathcal{H}$ which may be expressed as the commutator of two idempotent operators. In particular, we will identify which biquasitriangular operators belong to the norm-closure of $\mathfrak{C}_{\mathfrak{E}}$.
　　If time permitted, we will also give characterizations of matrices could be expressed as the commutator of two square zero matrices, and some related results about limits of commutators of two square zero operators acting on $\mathcal{H}$.
　　This is based on joint papers with Laurent Marcoux and Heydar Radjavi.