Let T be a self-adjoint tridiagonal operator in a Hilbert space H with the orthonormal basis {e n}n=1∞, σ(T) be the spectrum of T and Λ(T) be the set of all the limit points of eigenvalues of the truncated operator T N. We give sufficient conditions such that the spectrum of T is discrete and σ(T) = Λ(T) and we connect this problem with an old problem in analysis.
@article{bwmeta1.element.doi-10_2478_s11533-007-0009-1,
author = {E.K. Ifantis and C.G. Kokologiannaki and E. Petropoulou},
title = {Limit points of eigenvalues of truncated unbounded tridiagonal operators},
journal = {Open Mathematics},
volume = {5},
year = {2007},
pages = {335-344},
zbl = {1130.47002},
language = {en},
url = {http://dml.mathdoc.fr/item/bwmeta1.element.doi-10_2478_s11533-007-0009-1}
}
E.K. Ifantis; C.G. Kokologiannaki; E. Petropoulou. Limit points of eigenvalues of truncated unbounded tridiagonal operators. Open Mathematics, Tome 5 (2007) pp. 335-344. http://gdmltest.u-ga.fr/item/bwmeta1.element.doi-10_2478_s11533-007-0009-1/
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