科研之友
微信
新浪微博
Facebook
分享链接
摘要
Let H be a complex Hilbert space and let A = (A1,..., An) be an ntuple of self-adjoint operators on H. The joint numerical range of A is the set W(A) = {( A1x, x ,..., Anx, x ) : x is a unit vector in H}. By a result of Li and Poon, the closure of W(A), denoted by W(A)-, is star-shaped with each point in the joint essential numerical range of A a star centre. In this note, we give a few observations about the boundary of W(A) and W(A)-basing on their results.
- 出版日期2018
- 单位香港大学
