A Toeplitz-like operator with rational symbol having poles on the unit circle II: the spectrum

G. J. Groenewald, S. ter Horst, J. Jaftha, A. C. M. Ran

Published 2018-04-24Version 1

This paper is a continuation of our study of a class of Toeplitz-like operators with a rational symbol which has a pole on the unit circle. A description of the spectrum and its various parts, i.e., point, residual and continuous spectrum, is given, as well as a description of the essential spectrum. In this case, the essential spectrum need not be connected in ${\mathbb C}$. Various examples illustrate the results.