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arXiv · 0711.2771

Analytic approximation of matrix functions and dual extremal functions

V. V. Peller
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Abstract

We study the question of the existence of a dual extremal function for a bounded matrix function on the unit circle in connection with the problem of approximation by analytic matrix functions. We characterize the class of matrix functions, for which a dual extremal function exists in terms of the existence of a maximizing vector of the corresponding Hankel operator and in terms of certain special factorizations that involve thematic matrix functions.

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V. V. Peller. 2008-01-02. Analytic approximation of matrix functions and dual extremal functions. https://arxiv.org/abs/0711.2771

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