Let T be a bounded linear operator on a complex Hilbert space H. In this paper we introduce a new class, denoted *, of operators satisfying where k is a natural number, and we prove basic structural properties of these operators. Using these results, we also show that if E is the Riesz idempotent for a non-zero isolated point μ of the spectrum of T ∈ *, then E is self-adjoint and EH = ker(T-μ) = ker(T-μ)*. Some spectral properties are also presented.
@article{bwmeta1.element.bwnjournal-article-doi-10_4064-sm208-1-6,
author = {Salah Mecheri},
title = {Isolated points of spectrum of k-quasi-*-class A operators},
journal = {Studia Mathematica},
volume = {209},
year = {2012},
pages = {87-96},
zbl = {1250.47040},
language = {en},
url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-sm208-1-6}
}
Salah Mecheri. Isolated points of spectrum of k-quasi-*-class A operators. Studia Mathematica, Tome 209 (2012) pp. 87-96. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-sm208-1-6/