7 citations · 20 across the 18 of their papers we have counts for
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Optimal interpolation in Hardy and Bergman spaces: a reproducing kernel Banach space approach
Gilbert J. Groenewald, Sanne ter Horst, Hugo J. Woerdeman
After a review of the reproducing kernel Banach space framework and semi-inner products, we apply the techniques to the setting of Hardy spaces and Bergman spaces , $1<p…
Indefinite determinantal representations versus nonsingularities on the noncommutative d-torus
Gilbert J. Groenewald, Sanne ter Horst, Hugo J. Woerdeman
We show that for a multivariable polynomial with a determinantal representation the matrix $…
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: Invertibility and Riccati equations
G. J. Groenewald, S. ter Horst, J. Jaftha +1
This paper is a continuation of the work on unbounded Toeplitz-like operators $T_\Om$ with rational matrix symbol $\Om$ initiated in Groenewald et. al (Complex Anal. Oper. Theory 1…
A Toeplitz-like operator with rational matrix symbol having poles on the unit circle: Fredholm characteristics
G. J. Groenewald, S. ter Horst, J. J. Jaftha +1
In a recent paper (Groenewald et al.\ {\em Complex Anal.\ Oper.\ Theory} \textbf{15:1} (2021)) we considered an unbounded Toeplitz-like operator generated by a rational matri…
Wiener-Hopf factorization indices of rational matrix functions with respect to the unit circle in terms of realization
G. J. Groenewald, M. A. Kaashoek, A. C. M. Ran
As in the paper [G. Groenewald, M.A. Kaashoek, A.C.M. Ran, Wiener-Hopf indices of unitary functions on the unit circle in terms of realizations and related results on Toeplitz oper…