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Main Authors: Aleman, Alexandru, Richter, Stefan
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2409.20298
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author Aleman, Alexandru
Richter, Stefan
author_facet Aleman, Alexandru
Richter, Stefan
contents Let $D(μ)$ denote a harmonically weighted Dirichlet space on the unit disc $\mathbb D$. We show that outer functions $f\in D(μ)$ are cyclic in $D(μ)$, whenever $\log f$ belongs to the Pick-Smirnov class $N^+(D(μ))$. If $f$ has $H^\infty$-norm less than or equal to 1, then cyclicity can also be checked via iterated logarithms. For example, we show that such outer functions $f$ are cyclic, whenever $\log(1+ \log(1/f))\in N^+(D(μ))$. This condition can be checked by verifying that $\log(1+ \log(1/f))\in D(μ)$. If $f$ satisfies a mild extra condition, then the conditions also become necessary for cyclicity.
format Preprint
id arxiv_https___arxiv_org_abs_2409_20298
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Cyclicity and iterated logarithms in the Dirichlet space
Aleman, Alexandru
Richter, Stefan
Functional Analysis
Let $D(μ)$ denote a harmonically weighted Dirichlet space on the unit disc $\mathbb D$. We show that outer functions $f\in D(μ)$ are cyclic in $D(μ)$, whenever $\log f$ belongs to the Pick-Smirnov class $N^+(D(μ))$. If $f$ has $H^\infty$-norm less than or equal to 1, then cyclicity can also be checked via iterated logarithms. For example, we show that such outer functions $f$ are cyclic, whenever $\log(1+ \log(1/f))\in N^+(D(μ))$. This condition can be checked by verifying that $\log(1+ \log(1/f))\in D(μ)$. If $f$ satisfies a mild extra condition, then the conditions also become necessary for cyclicity.
title Cyclicity and iterated logarithms in the Dirichlet space
topic Functional Analysis
url https://arxiv.org/abs/2409.20298