Inner approximations of doubling weights with applications to Beurling-Malliavin theory in Toeplitz kernels

Fuente: arXiv
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Main Author: Bergman, Alex
Format: Preprint
Published: 2025
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author Bergman, Alex
author_facet Bergman, Alex
contents A meromorphic inner function is a bounded holomorphic function in the upper half-plane which is unimodular on the real line and extends to a meromorphic function in the whole complex plane. The argument of a meromorphic inner function on the real line is a strictly increasing function. It turns out that it is important for many problems in function theory to approximate an arbitrary increasing function, $f$, by the argument of a meromorphic inner function. Depending on desired approximation this is a delicate problem. In this paper consider the case when $f$ satisfies a doubling condition. We give two applications of our main result. The first is a sufficient density condition for a set $Λ$ to be a zero set for a Toeplitz kernel with real analytic and unimodular symbol. Our second application is to describe a class of admissible Beurling-Malliavin majorants in model spaces. The generality considered here lets us treat most cases of model spaces generated by meromorphic one-component inner functions.
format Preprint
id arxiv_https___arxiv_org_abs_2509_21229
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Inner approximations of doubling weights with applications to Beurling-Malliavin theory in Toeplitz kernels
Bergman, Alex
Classical Analysis and ODEs
Complex Variables
Functional Analysis
42C05, 30H10, 30J05
A meromorphic inner function is a bounded holomorphic function in the upper half-plane which is unimodular on the real line and extends to a meromorphic function in the whole complex plane. The argument of a meromorphic inner function on the real line is a strictly increasing function. It turns out that it is important for many problems in function theory to approximate an arbitrary increasing function, $f$, by the argument of a meromorphic inner function. Depending on desired approximation this is a delicate problem. In this paper consider the case when $f$ satisfies a doubling condition. We give two applications of our main result. The first is a sufficient density condition for a set $Λ$ to be a zero set for a Toeplitz kernel with real analytic and unimodular symbol. Our second application is to describe a class of admissible Beurling-Malliavin majorants in model spaces. The generality considered here lets us treat most cases of model spaces generated by meromorphic one-component inner functions.
title Inner approximations of doubling weights with applications to Beurling-Malliavin theory in Toeplitz kernels
topic Classical Analysis and ODEs
Complex Variables
Functional Analysis
42C05, 30H10, 30J05
url https://arxiv.org/abs/2509.21229