AM  Vol.4 No.11 A , November 2013
Spectra of 2 × 2 Upper-Triangular Operator Matrices
Author(s) Haiyan Zhang
ABSTRACT

In [Perturbation of Spectrums of 2 × 2 Operator Matrices, Proceedings of the American Mathematical Society, Vol. 121, 1994], the authors asked whether there was an operator  such that  for a given pair (A,B) of operators, where the operator  was defined by . In this note, a partial answer for the question is given.


Cite this paper
H. Zhang, "Spectra of 2 × 2 Upper-Triangular Operator Matrices," Applied Mathematics, Vol. 4 No. 11, 2013, pp. 22-25. doi: 10.4236/am.2013.411A1004.
References
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[7]   Y. Li, X. H. Sun and H. K. Du, “Inversctions of the Left and Right Essential Spectra of 2 × 2 Upper Triangular Operator Matrices,” Bulletin London Mathematical Society, Vol. 36, 2004, pp. 811-819.

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