Analytic approximation of matrix functions and dual extremal functions
Functional Analysis
2008-01-03 v2 Classical Analysis and ODEs
Complex Variables
Spectral Theory
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.
Cite
@article{arxiv.0711.2771,
title = {Analytic approximation of matrix functions and dual extremal functions},
author = {V. V. Peller},
journal= {arXiv preprint arXiv:0711.2771},
year = {2008}
}