Abstract
Let S be a band in Z2 bordered by two parallel lines that are of equal distance to the origin. Given a positive definite ℓ1 sequence of matrices {cj}j∈S, we prove that there is a positive definite matrix function f in the Wiener algebra on the bitorus such that the Fourier coefficients f(k) equal ck for k ∈ S. A parameterization is obtained for the set of all positive extensions f of {cj}j∈S. We also prove that among all matrix functions with these properties, there exists a distinguished one that maximizes the entropy. A formula is given for this distinguished matrix function. The results are interpreted in the context of spectral estimation of ARMA processes.
Original language | English (US) |
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Pages (from-to) | 20-44 |
Number of pages | 25 |
Journal | Journal of Fourier Analysis and Applications |
Volume | 5 |
Issue number | 1 |
DOIs | |
State | Published - 1999 |
Keywords
- ARMA processes
- Almost periodic functions
- Band method
- Entropy
- Matrix functions on bitorus
- Positive extensions
- Toeplitz operators
- Wiener algebra
ASJC Scopus subject areas
- Analysis
- General Mathematics
- Applied Mathematics