Matrices with Circular Symmetry on Their Unitary Orbits and C-numerical Ranges
نویسنده
چکیده
We give equivalent characterizations for those n x n complex matrices A whose unitary orbits %?(A) and C-numerical ranges WC{A) satisfy ei8&(A) = f/(A) or e'e WC(A) = WC(A) for some real 0 (or for all real 0 ). In particular, we show that they are the block-cyclic or block-shift operators. Some of these results are extended to infinite-dimensional Hubert spaces.
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تاریخ انتشار 2010