主講人：張福振 美國諾瓦東南大學教授

時間：2024年6月14日13：30

地點：三號樓332室

舉辦單位：數理學院

主講人介紹：張福振，現為美國Nova Southeastern University（諾瓦東南大學）數學系教授。主要研究線性與多重線性代數及矩陣分析、算子理論、泛函分析和組合數學。至今發表學術論文80余篇，著作3部。曾任美國數學會《數學評論》 評審人,國際線性代數學會公報《IMAGE》編委,美國自然科學基金評委。現任多家國際數學雜志編委或客座編委。若干國際數學專業會議主講人,其中包括第18屆國際線性代數學會大會，第22屆國際矩陣與統計研討班，和田納西大學線性代數及圖論會。國際矩陣分析及應用系列會議組委會主席。第19屆國際線性代數學會大會組委會成員。在世界各地專業會議中報告80余次。近年來在中國一些高校就中美高等教育演講。被聘為上海大學等高校兼職教授。參與創建佛州華人華僑聯合會，并曾任主席(1994-1996)，南佛州現代中文學校校長等職。2013年獲諾瓦東南大學文理學院杰出教授獎。

內容介紹：Are eigenvalues continuous functions of matrix entries? In other words, do the eigenvalues of a matrix change continuously as the matrix itself undergoes small changes? (The answer is yes or no, depending on what is meant by eigenvalue continuity). Eigenvalue continuity is a fundamental concept in linear algebra and matrix theory that provides insights into the behavior of eigenvalues under small changes to matrices, with wide-ranging implications in theory and applications. However, eigenvalue continuity has been misused or carelessly used. We discuss the continuity of eigenvalues as functions (functional continuity) as well as in the topological sense (topological continuity). This talk is also concerned with a few issues of linear algebra, both in teaching and research. These issues are usually overlooked or carelessly treated in texts or teaching.