报告时间：2024年9月29日（周日）下午16:30-17:30

报告地点：主楼H203

报告摘要：This talk is concerned with essential spectra of Hamiltonian systems with one singular endpoint. The characterization of each element of the essential spectrum in terms of certain singular sequences is given, the concept of perturbation small at the singular endpoint is introduced, and the stability of the essential spectrum is obtained under this perturbation. Some sufficient conditions for the invariance of the essential spectrum are given in terms of coefficients of Hamiltonian systems. In addition，the corresponding results are obtained for the essential numerical ranges of semi-bounded systems.

报告人简介：孙华清，东北大学教授，博士生导师，东北大学数学与交叉科学研究中心主任，微分方程及其应用辽宁省教育厅重点实验室主任，辽宁省数学会数学交叉与应用委员会主任，入选市级人才计划。从事奇异微分与差分算子谱理论研究，在“J. Funct. Anal.”，“J. Differential Equations”，“Proc. Roy. Soc. Edinburgh Sect. A”，“Stud. Math. Appl.”等国际权威杂志上发表和接受30多篇。曾主持完成国家自然科学基金项目和省部级项目多项，参与国家级和省级项目多项。