Themes

Numerical Range

Akio Arimoto

numerical range の話題

numerical range for nilpotent matrix now

note on the numerical ranges which give polygon and inscribed circle

The numerical range for a nilpotent operator is a disk
unpublished (2004)

U.Haagerup and P.de la Harpe,
The numerical radius of a nilpotent operator on a Hilbert space,
Proc.Amer.Math.Soc.115(1992)371-379

J.S.Lancaster
The boundary of the numerical range
Proc.Amer.Math.Soc.49(1975)393-398

C.K.Li and N.K.Tsing
Matrices with circular symmetry on their unitary orbits and C-numerical range
Proc.Amer.Math.Soc.111(1991)19-28

Chi-Kwong Li
A Simple Proof of the Eloptical Range Theorem
Proc.Amer.Math.Soc.124(1996)1985-6
A short proof is given of the ellliptical range theorem concerning the numerical range of a 2x2
complex matrix.

Notes on the Numerical Range
unpublished
Joel H.Shapiro
Corespondence with me

The Numerical Range of a Nilpotent Operator on a Hilbert Space
proceedings of AMS,2004,S0002-9939(04)07391-5
Mubaritz T.Karaev
Corespondence with me