Ebook: Approximation of Hilbert Space Operators

The purpose of this monograph (and a second one, by C. Apostol,
L. A. Fialkow, D. A. Herrero and D. Voiculescu that will follow and
complete the results contained here) is to provide a set of general
arguments to deal with approximation problems (in the norm-topology)
related to those subsets of the algebra L[H) of all operators acting
on a complex separable infinite dimensional Hubert space that are
invariant under similarities.