On superoptimal approximation by analytic and meromorphic matrix-valued functions

DOI10.1006/jfan.1995.1094zbMath0877.47008OpenAlexW2005784427MaRDI QIDQ1897280

S. R. Treil'

Publication date: 8 December 1997

Published in: Journal of Functional Analysis (Search for Journal in Brave)

Full work available at URL: https://doi.org/10.1006/jfan.1995.1094

zbMATH Keywords

geometric approachsuperoptimal approximationsuperoptimal singular valuesHankel operatorNehari problemHardy class\(s\)-numbersunique best approximationoperator-valued functionsmeromorphic matrix-valued functionssuperoptimal solution

Mathematics Subject Classification ID

Best approximation, Chebyshev systems (41A50) Riesz operators; eigenvalue distributions; approximation numbers, (s)-numbers, Kolmogorov numbers, entropy numbers, etc. of operators (47B06) Toeplitz operators, Hankel operators, Wiener-Hopf operators (47B35) Functions whose values are linear operators (operator- and matrix-valued functions, etc., including analytic and meromorphic ones) (47A56)

Related Items (9)

Construction of superoptimal approximants ⋮ Approximation by analytic matrix functions: The four block problem ⋮ An explicit state-space solution to the one-block super-optimal distance problem ⋮ An index formula in connection with meromorphic approximation ⋮ Approximation by analytic operator functions. Factorizations and very badly approximable functions ⋮ Unitary interpolants and factorization indices of matrix functions. ⋮ Invariance properties of thematic factorizations of matrix functions ⋮ The 2-block superoptimal AAK problem ⋮ Factorization and approximation problems for matrix functions

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