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Can I read Higher Rank Numerical Ranges of Normal Operators and Unitary Dilations on EtoBox?
Higher Rank Numerical Ranges of Normal Operators and Unitary Dilations by Pankaj Dey; Mithun Mukherjee is a Mathematics article available to read on EtoBox.
What is Higher Rank Numerical Ranges of Normal Operators and Unitary Dilations about?
Here we give a closure free description of the higher rank numerical range of a normal operator acting on a separable Hilbert space. This generalizes a result of Avendaño for self-adjoint operators. It has several interesting applications. We show using Durszt's example that there exists a normal contraction T for which the intersection of the higher rank numerical ranges of all unitary dilations of T contains the higher rank numerical range of T as a proper subset. We strengthen and generalize a result of Wu by providing a necessary and sufficient condition for the higher rank numerical range of a normal contraction being equal to the intersection of the higher rank numerical ranges of all possible unitary dilations of it. We also show that the above condition is necessary for a general contraction.
Who reads Higher Rank Numerical Ranges of Normal Operators and Unitary Dilations?
It is typically read by researchers, students, and practitioners in Mathematics.
- Author
- Pankaj Dey; Mithun Mukherjee
- Publisher
- Elsevier BV
- Published
- 2023
- Language
- EN
- Field
- Mathematics (Physical Sciences)