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

In Ho Jeon, In Hyoun Kim


In the present note, provided $T\in\mathscr{L(H)}$ is biquasitriangular and Browder's theorem hold for $T$, we show that the spectrum $\sigma$ is continuous at $T$ if and only if the essential spectrum $\sigma_{e}$ is continuous at $T$.


spectral continuity, biquasitriangular

Subject classification

47A10, 47A53, 47B20


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

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