Numerical ranges of some Foguel operators
نویسندگان
چکیده
منابع مشابه
Numerical ranges of composition operators
Composition operators on the Hilbert Hardy space of the unit disk are considered. The shape of their numerical range is determined in the case when the symbol of the composition operator is a monomial or an inner function fixing 0. Several results on the numerical range of composition operators of arbitrary symbol are obtained. It is proved that 1 is an extreme boundary point if and only if 0 i...
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15 صفحه اولSome Constants Related to Numerical Ranges
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The classical numerical range of a quadratic operator is an elliptical disk. This result is extended to different kinds of generalized numerical ranges. In particular, it is shown that for a given quadratic operator, the rank-k numerical range, the essential numerical range, and the q-numerical range are elliptical disks; the c-numerical range is a sum of elliptical disks, and the Davis-Wieland...
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ژورنال
عنوان ژورنال: Operators and Matrices
سال: 2023
ISSN: ['1848-9974', '1846-3886']
DOI: https://doi.org/10.7153/oam-2023-17-14