51 citations · 394 across the 42 of their papers we have counts for
17 papers · 1 filter
Commuting normal operators and joint numerical range
Jor-Ting Chan, Chi-Kwong Li, Yiu-Tung Poon
Let be a complex Hilbert space and let be the algebra of all bounded linear operators on . For a positive integer less…
The joint -numerical range of operators
Jor-Ting Chan, Chi-Kwong Li, Yiu-Tung Poon
Let be the algebra of all bounded linear operators on the Hilbert space . For a positive integer less than the dimension of ${\mathca…
Joint numerical ranges and communtativity of matrices
Chi-Kwong Li, Yiu-Tung Poon, Ya-Shu Wang
The connection between the commutativity of a family of matrices and the generalized joint numerical ranges is studied. For instance, it is shown that is a f…
Numerical Range Inclusion, Dilation, and Operator Systems
Chi-Kwong Li, Yiu-Tung Poon
Researchers have identified complex matrices such that a bounded linear operator acting on a Hilbert space will admit a dilation of the form whenever the nume…
Submultiplicativity of the numerical radius of commuting matrices of order two
Chi-Kwong Li, Yiu-Tung Poon
Denote by the numerical radius of a matrix . An elementary proof is given to the fact that for a pair of commuting matrices of order two, and charac…
Numerical Range Inclusion, Dilation, and completely positive maps
Chi-Kwong Li, Yiu-Tung Poon
A proof using the theory of completely positive maps is given to the fact that if , or has a reducing eigenvalue, then every bounded linear operator with…