TY - JOUR
T1 - Wiener-Hopf indices of unitary functions on the unit circle in terms of realizations and related results on Toeplitz operators.
AU - Ran, André
AU - Kaashoek, M.A.
AU - Groenewald, Gilbert
PY - 2017/6
Y1 - 2017/6
N2 - We provide new formulas for the Wiener–Hopf factorization indices of a rational matrix function R which has neither poles nor zeros on the unit circle. In addition, we recover recent results on the Fredholm characteristics of the Toeplitz operator with symbol R via the method of matricial coupling. Furthermore, we present an alternative formula for the index in terms of the Fourier coefficients of R.
AB - We provide new formulas for the Wiener–Hopf factorization indices of a rational matrix function R which has neither poles nor zeros on the unit circle. In addition, we recover recent results on the Fredholm characteristics of the Toeplitz operator with symbol R via the method of matricial coupling. Furthermore, we present an alternative formula for the index in terms of the Fourier coefficients of R.
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U2 - 10.1016/j.indag.2017.03.001
DO - 10.1016/j.indag.2017.03.001
M3 - Article
SN - 0019-3577
VL - 28
SP - 694
EP - 710
JO - Indagationes Mathematicae
JF - Indagationes Mathematicae
IS - 3
ER -