4 papers · 1 filter
A Toeplitz-like operator with rational matrix symbol having poles on the unit circle:\ Matrix representation and spectral analysis
G. J. Groenewald, S. ter Horst, J. Jaftha +1
In this paper we consider a class of unbounded Toeplitz operators with rational matrix symbols that have poles on the unit circle and employ state space realization techniques from…
A Toeplitz-like operator with rational matrix symbol having poles on the unit circle: Fredholm properties
G. J. Groenewald, S. ter Horst, J. Jaftha +1
This paper concerns the analysis of an unbounded Toeplitz-like operator generated by a rational matrix function having poles on the unit circle T. It extends the analysis of such o…
Equivalence after extension and Schur coupling do not coincide, on essentially incomparable Banach spaces
Sanne ter Horst, Miek Messerschmidt, Andre C. M. Ran +1
In 1994 H. Bart and V.É. Tsekanovskii posed the question whether the Banach space operator relations matricial coupling (MC), equivalence after extension (EAE) and Schur coupling (…
Equivalence after extension and Schur coupling coincide for inessential operators
S. ter Horst, M. Messerschmidt, A. C. M. Ran +2
In recent years the coincidence of the operator relations equivalence after extension (EAE) and Schur coupling (SC) was settled for the Hilbert space case. For Banach space operato…