IUMJ

Title: A coordinate free characterization of certain quasidiagonal operators

Authors: March Boedihardjo

Issue: Volume 64 (2015), Issue 2, 515-531

Abstract:

We obtain the following: \begin{enumerate}[label=(\roman*)] \item a new, coordinate-free characterization of quasidiagonal operators with essential spectra contained in the unit circle by adapting the proof of a classical result in the theory of Banach spaces, \item affirmative answers to some questions of Hadwin \item an alternative proof of Hadwin's characterization of the SOT, WOT, and $*$-SOT closure of the unitary orbit of a given operator on a separable, infinite-dimensional, complex Hilbert space. \end{enumerate}