Korean J. Math. Vol. 23 No. 4 (2015) pp.601-605
DOI: https://doi.org/10.11568/kjm.2015.23.4.601

A note on spectral continuity

Main Article Content

In Ho Jeon
In Hyoun Kim

Abstract

In the present note, provided TL(H) is biquasitriangular and Browder's theorem hold for T, we show that the spectrum σ is continuous at T if and only if the essential spectrum σe is continuous at T.


Article Details

Supporting Agencies

This work was supported by the Incheon National University Research Grant in 2013

References

[1] C. Apostol, C. Foias and D. Voiculescu, Some results on non-quasitriangular operators. IV, Rev. Roum. Math. Pures Appl. 18 (1973), 487–514. Google Scholar

[2] J. B. Conway and B. B. Morrel, Operators that are points of spectral continuity, Integral equations and operator theory, 2 (1979), 174-198. Google Scholar

[3] J. B. Conway and B. B. Morrel, Operators that are points of spectral continuity II, Integral equations and operator theory 4 (1981), 459-503. Google Scholar

[4] N. Dunford, Spectral operators, Pacific J. Math. 4 (1954), 321–354. Google Scholar

[5] S. V. Djordjevi c and B. P. Duggal, Weyl's theorem and continuity of spectra in the class of p-hyponormal operators, Studia Math. 143 (2000), 23-32. Google Scholar

[6] S. V.Djordjevi c and Y. M. Han, Browder's theorem and spectral continuity, Glasgow Math. J. 42 (2000), 479-486. Google Scholar

[7] S. V.Djordjevi c, Continuity of the essential spectrum in the class of quasihyponormal operators, Vesnik Math. 50 (1998) 71-74. Google Scholar

[8] B. P. Duggal, I. H. Jeon, and I. H. Kim, Continuity of the spectrum on a class of upper triangular operator matrices, Jour. Math. Anal. Appl. 370 (2010), 584–587. Google Scholar

[9] R. Harte and W. Y. Lee, Another note on Weyl’s theorem, Trans. Amer. Math. Soc. 349 (1997), 2115–2124. Google Scholar

[10] I. S. Hwang and W. Y. Lee, The spectrum is continuous on the set of phyponormal operators, Math. Z. 235 (2000), 151–157. Google Scholar

[11] R. Lange, Biquasitriangularity and spectral continuity, Glasgow Math. J. 26 (1985), 177–180. Google Scholar

[12] J. D. Newburgh, The variation of spectra, Duke Math. J. 18 (1951), 165–176. Google Scholar