Matrices with circular symmetry on their unitary orbits and $C$-numerical ranges
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- by Chi-Kwong Li and Nam-Kiu Tsing PDF
- Proc. Amer. Math. Soc. 111 (1991), 19-28 Request permission
Abstract:
We give equivalent characterizations for those $n \times n$ complex matrices $A$ whose unitary orbits $\mathcal {U}(A)$ and $C$-numerical ranges ${W_C}(A)$ satisfy ${e^{i\theta }}\mathcal {U}(A) = \mathcal {U}(A)$ or ${e^{i\theta }}{W_C}(A) = {W_C}(A)$ for some real $\theta$ (or for all real $\theta$). In particular, we show that they are the block-cyclic or block-shift operators. Some of these results are extended to infinite-dimensional Hilbert spaces.References
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Additional Information
- © Copyright 1991 American Mathematical Society
- Journal: Proc. Amer. Math. Soc. 111 (1991), 19-28
- MSC: Primary 15A60; Secondary 47A12, 47C99
- DOI: https://doi.org/10.1090/S0002-9939-1991-1041014-5
- MathSciNet review: 1041014