報告題目：Around the commutators of quadratic operators
報告人：張遠航教授
報告時間：2023.12.7 15：30-16：30
報告地點：數(shù)學(xué)與統(tǒng)計學(xué)院 104報告廳
報告人簡介：張遠航，吉林大學(xué)數(shù)學(xué)學(xué)院教授，博士生導(dǎo)師，主要研究興趣包括：C*-代數(shù)分類理論及應(yīng)用、套代數(shù)的可逆元群連通性問題、有界線性算子的交換子、矩陣代數(shù)的非對角塊。已在JFA、JNCG、JOT、Studia Math.、PAMS、IEOT及中國科學(xué)(中、英文版)等雜志上發(fā)表(含已接受)學(xué)術(shù)論文10多篇。現(xiàn)主持國家自然科學(xué)基金面上基金一項。
報告內(nèi)容簡介：
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.
