Product of two diagonal entries of a 3-by-3 normal matrix. (English) Zbl 06883431
Summary: The set of product of two diagonal entries of 3-by-3 normal matrices unitarily similar to a diagonal matrix is a triangle if the diagonal entries form an acute-angled triangle inscribed to the unit circle.
MSC:
| 47A12 | Numerical range, numerical radius |
References:
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