The Maximum Locus of the Bloch Norm

For a Bloch function f in the unit ball in ℂn, we study the maximal locus of the Bloch norm of f; namely, the set Lf where the Bergman length of the gradient vector field of f attains its maximum. We prove that for n ≥, the set Lf consists of a finite union of real analytic sets with dimensions at m...

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Main Author: El Hassan Youssfi
Format: Article
Language:English
Published: Sciendo 2023-05-01
Series:Moroccan Journal of Pure and Applied Analysis
Subjects:
Online Access:https://doi.org/10.2478/mjpaa-2023-0019
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author El Hassan Youssfi
author_facet El Hassan Youssfi
author_sort El Hassan Youssfi
collection DOAJ
description For a Bloch function f in the unit ball in ℂn, we study the maximal locus of the Bloch norm of f; namely, the set Lf where the Bergman length of the gradient vector field of f attains its maximum. We prove that for n ≥, the set Lf consists of a finite union of real analytic sets with dimensions at most 2n − 2. This is not the case for n = 1 as was proved earlier by Cima and Wogen. We also give some rigidity properties of the set Lf. In particular, we give some sufficient criteria for constructing extreme functions in the Little Bloch ball.
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spelling doaj.art-2c870c19103f423f8e4af4c074aa9ad92023-06-12T06:33:05ZengSciendoMoroccan Journal of Pure and Applied Analysis2351-82272023-05-019229130310.2478/mjpaa-2023-0019The Maximum Locus of the Bloch NormEl Hassan Youssfi01I2M UMR 7373, Université d’Aix-Marseille, 39 Rue Joliot-Curie 13453 Marseille Cedex 13, France.For a Bloch function f in the unit ball in ℂn, we study the maximal locus of the Bloch norm of f; namely, the set Lf where the Bergman length of the gradient vector field of f attains its maximum. We prove that for n ≥, the set Lf consists of a finite union of real analytic sets with dimensions at most 2n − 2. This is not the case for n = 1 as was proved earlier by Cima and Wogen. We also give some rigidity properties of the set Lf. In particular, we give some sufficient criteria for constructing extreme functions in the Little Bloch ball.https://doi.org/10.2478/mjpaa-2023-0019bergman kernelbergman metricbloch functionbloch32a18
spellingShingle El Hassan Youssfi
The Maximum Locus of the Bloch Norm
Moroccan Journal of Pure and Applied Analysis
bergman kernel
bergman metric
bloch function
bloch
32a18
title The Maximum Locus of the Bloch Norm
title_full The Maximum Locus of the Bloch Norm
title_fullStr The Maximum Locus of the Bloch Norm
title_full_unstemmed The Maximum Locus of the Bloch Norm
title_short The Maximum Locus of the Bloch Norm
title_sort maximum locus of the bloch norm
topic bergman kernel
bergman metric
bloch function
bloch
32a18
url https://doi.org/10.2478/mjpaa-2023-0019
work_keys_str_mv AT elhassanyoussfi themaximumlocusoftheblochnorm
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