A NOTE ON *-PARANORMAL OPERATORS AND RELATED CLASSES OF OPERATORS
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We shall show that the Riesz idempotent E of every ∗- paranormal operator T on a complex Hilbert space H with respect to each isolated point of its spectrum (T) is self-adjoint and satisfies EH = ker(T − ) = ker(T − )∗. Moreover, Weyl’s theorem holds for ∗-paranormal operators and more general for operators T satisfying the norm condition ∥Tx∥n ≤ ∥Tnx∥∥x∥n−1 for all x ∈ H. Finally, for this more general class of operators we find a sufficient condition such that EH = ker(T − ) = ker(T − )∗ holds.
Abstract
We shall show that the Riesz idempotent E of every ∗- paranormal operator T on a complex Hilbert space H with respect to each isolated point of its spectrum (T) is self-adjoint and satisfies EH = ker(T − ) = ker(T − )∗. Moreover, Weyl’s theorem holds for ∗-paranormal operators and more general for operators T satisfying the norm condition ∥Tx∥n ≤ ∥Tnx∥kx∥n−1 for all x ∈ H. Finally, for this more general class of operators we find a sufficient condition such that EH = ker(T − ) = ker(T − )∗ holds.
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