Beurling-Carleson sets, inner functions and a semi-linear equation

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Ivrii, Oleg, Nicolau, Artur
Format: Preprint
Published: 2022
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866929476151017472
author Ivrii, Oleg
Nicolau, Artur
author_facet Ivrii, Oleg
Nicolau, Artur
contents Beurling-Carleson sets have appeared in a number of areas of complex analysis such as boundary zero sets of analytic functions, inner functions with derivative in the Nevanlinna class, cyclicity in weighted Bergman spaces, Fuchsian groups of Widom-type and the corona problem in quotient Banach algebras. After surveying these developments, we give a general definition of Beurling-Carleson sets and discuss some of their basic properties. We show that the Roberts decomposition characterizes measures that do not charge Beurling-Carleson sets. For a positive singular measure $μ$ on the unit circle, let $S_μ$ denote the singular inner function with singular measure $μ$. In the second part of the paper, we use a corona-type decomposition to relate a number of properties of singular measures on the unit circle such as membership of $S'_μ$ in the Nevanlinna class $\mathcal N$, area conditions on level sets of $S_μ$ and wepability. It was known that each of these properties holds for measures concentrated on Beurling-Carleson sets. We show that each of these properties implies that $μ$ lives on a countable union of Beurling-Carleson sets. We also describe partial relations involving the membership of $S'_μ$ in the Hardy space $H^p$, membership of $S_μ$ in the Besov space $B^p$ and $(1-p)$-Beurling-Carleson sets and give a number of examples which show that our results are optimal. Finally, we show that measures that live on countable unions of $α$-Beurling-Carleson sets are almost in bijection with nearly-maximal solutions of $Δu = u^p \cdot χ_{u > 0}$ when $p > 3$ and $α= \frac{p-3}{p-1}$.
format Preprint
id arxiv_https___arxiv_org_abs_2210_01270
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Beurling-Carleson sets, inner functions and a semi-linear equation
Ivrii, Oleg
Nicolau, Artur
Complex Variables
Analysis of PDEs
Classical Analysis and ODEs
Beurling-Carleson sets have appeared in a number of areas of complex analysis such as boundary zero sets of analytic functions, inner functions with derivative in the Nevanlinna class, cyclicity in weighted Bergman spaces, Fuchsian groups of Widom-type and the corona problem in quotient Banach algebras. After surveying these developments, we give a general definition of Beurling-Carleson sets and discuss some of their basic properties. We show that the Roberts decomposition characterizes measures that do not charge Beurling-Carleson sets. For a positive singular measure $μ$ on the unit circle, let $S_μ$ denote the singular inner function with singular measure $μ$. In the second part of the paper, we use a corona-type decomposition to relate a number of properties of singular measures on the unit circle such as membership of $S'_μ$ in the Nevanlinna class $\mathcal N$, area conditions on level sets of $S_μ$ and wepability. It was known that each of these properties holds for measures concentrated on Beurling-Carleson sets. We show that each of these properties implies that $μ$ lives on a countable union of Beurling-Carleson sets. We also describe partial relations involving the membership of $S'_μ$ in the Hardy space $H^p$, membership of $S_μ$ in the Besov space $B^p$ and $(1-p)$-Beurling-Carleson sets and give a number of examples which show that our results are optimal. Finally, we show that measures that live on countable unions of $α$-Beurling-Carleson sets are almost in bijection with nearly-maximal solutions of $Δu = u^p \cdot χ_{u > 0}$ when $p > 3$ and $α= \frac{p-3}{p-1}$.
title Beurling-Carleson sets, inner functions and a semi-linear equation
topic Complex Variables
Analysis of PDEs
Classical Analysis and ODEs
url https://arxiv.org/abs/2210.01270