A note on spectral continuity and on spectral properties of essentially G₁ operators

Glenn Richard Luecke

Vol. 69 (1977), No. 1, 141–149

DOI: 10.2140/pjm.1977.69.141

Abstract

A bounded operator on a separable Hilbert space is essentially G₁ if the image of T in the Calkin algebra satisfies condition G₁. This paper contains results describing (1) isolated points of the essential spectrum of essentially G₁ operators, and (2) essentially G₁ operators whose essential spectrum lies on a smooth Jordan curve. Finally, the continuity of the essential spectrum, Weyl spectrum, and spectrum is discussed.

Mathematical Subject Classification 2000

Primary: 47B99

Milestones

Received: 3 November 1976

Published: 1 March 1977