Universal multipliers for Sub-Hardy Hilbert spaces

Fuente: arXiv
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Main Authors: Malman, Bartosz, Seco, Daniel
Format: Preprint
Published: 2024
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author Malman, Bartosz
Seco, Daniel
author_facet Malman, Bartosz
Seco, Daniel
contents To every non-extreme point $b$ of the unit ball of $\hil^\infty$ of the unit disk there corresponds a Pythagorean mate, a bounded outer function $a$ satisfying the equation $|a|^2 + |b|^2 = 1$ on the boundary of the disk. We study universal, i.e., simultaneous multipliers for families of de Branges-Rovnyak spaces $\hb$, and develop a general framework for this purpose. Our main results include a new proof of the Davis-McCarthy universal multiplier theorem for the class of all non-extreme spaces $\hb$, a characterization of the Lipschitz classes as the universal multipliers for spaces $\hb$ for which the quotient $b/a$ is contained in a Hardy space, and a similar characterization of the Gevrey classes as the universal multipliers for spaces $\hb$ for which $b/a$ is contained in a Privalov class.
format Preprint
id arxiv_https___arxiv_org_abs_2410_13438
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Universal multipliers for Sub-Hardy Hilbert spaces
Malman, Bartosz
Seco, Daniel
Functional Analysis
Complex Variables
Primary 30H45, Secondary 47B32
To every non-extreme point $b$ of the unit ball of $\hil^\infty$ of the unit disk there corresponds a Pythagorean mate, a bounded outer function $a$ satisfying the equation $|a|^2 + |b|^2 = 1$ on the boundary of the disk. We study universal, i.e., simultaneous multipliers for families of de Branges-Rovnyak spaces $\hb$, and develop a general framework for this purpose. Our main results include a new proof of the Davis-McCarthy universal multiplier theorem for the class of all non-extreme spaces $\hb$, a characterization of the Lipschitz classes as the universal multipliers for spaces $\hb$ for which the quotient $b/a$ is contained in a Hardy space, and a similar characterization of the Gevrey classes as the universal multipliers for spaces $\hb$ for which $b/a$ is contained in a Privalov class.
title Universal multipliers for Sub-Hardy Hilbert spaces
topic Functional Analysis
Complex Variables
Primary 30H45, Secondary 47B32
url https://arxiv.org/abs/2410.13438