演講公告

新聞標題：　( 2013-03-01 )

• 演講主題：Numerical ranges of nilpotent operators

• 主講人：吳培元 教授（交通大學 應數系）

• 演講日期：2013年3月5日(星期二) 下午3:00 –4:00

• 演講地點：(光復校區) 科學一館223室

• 茶會時間：當天下午1:30 (科學一館205室)

• 摘要內容：
  

  For a bounded linear operator A on a complex Hilbert space H, its numerical range W(A) is the subset of the complex plane consisting of all inner products of Ax and x, where x can be any unit vector in C^{n}. A classical result of Toeplitz-Hausdorff says that W(A) is always convex.
  In this talk, we will address the following three problems concerning the shape of the numerical range of a nilpotent operator A:
  (1) How is 0 situated in W(A)?
  (2) How many line segments can there be on the boundary of W(A)?
  (3) Can W(A) be equal to a noncircular elliptic disc?

go back