Kuo-Zhong Wang

activity

20132016

most citedNumerical Radii for Tensor Products of Matrices

9 citations · 12 across the 7 of their papers we have counts for

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4 papers · 1 filter

math.FA2015★ 2 cited

Numerical Ranges of the product of Operators

Hongke Du, Chi-Kwong Li, Kuo-Zhong Wang +2

We study containment regions of the numerical range of the product of operators $A$ and $B$ such that $W (A)$ and $W (B)$ are line segments. It is shown that the containment region i…

math.FA2014

The spectrum of the product of operators, and the product of their numerical ranges

Chi-Kwong Li, Ming-Cheng Tsai, Kuo-Zhong Wang +1

We show that a compact operator $A$ is a multiple of a positive semi-definite operator if and only if $$ σ(AB) \subseteq \overline{W(A)W(B)}, \quad\text{for all (rank one) operator…

math.FA2013★ 9 cited

Numerical Radii for Tensor Products of Matrices

Hwa-Long Gau, Kuo-Zhong Wang, Pei Yuan Wu

For $n$ -by- $n$ and $m$ -by- $m$ complex matrices $A$ and $B$ , it is known that the inequality $w (A \otimes B) \leq ∥ A ∥ w (B)$ holds, where $w (\cdot)$ and $∥ \cdot ∥$ denote, respectively…

math.FA2013

Zero-dilation Index of a Finite Matrix

Hwa-Long Gau, Kuo-Zhong Wang, Pei Yuan Wu

For an $n$ -by- $n$ complex matrix $A$ , we define its zero-dilation index $d (A)$ as the largest size of a zero matrix which can be dilated to $A$ . This is the same as the maximum $k$ …