Article
Limit points of eigenvalues of truncated unbounded tridiagonal operators
Central European Journal of Mathematics
(Impact Factor: 0.52).
05/2007;
5(2):335344.
DOI: 10.2478/s1153300700091
ABSTRACT Let T be a selfadjoint 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.

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