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(2003 / vol.6 / no.2)
SPECTRAL PROPERTIES OF CLASS A OPERATORS
DERMING WANG, JUN IK LEE
Pages. 93-98     



Let $T$ be a class A operator. It is shown that (i) every
eigenvector of $T$ corresponding to a nonzero eigenvalue is a
normal eigenvector, (ii) every approximate eigenvector of $T$
correseponding to a nonzero approximate eigenvalue is a normal
approximate eigenvector, and (iii) $T$ is normal if the planar
Lebesque measure of the spectrum of $T$ is zero.



1. Introduction
2. Eigenvectors and approximate eigenvectors
3. The normality



Hyponormal, $p$- and $w$-hyponormal and class A operators



47A10, 47A53