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arXiv · 1909.03393

Extreme points and support points of families of harmonic Bloch mappings

Hua Deng·Saminthan Ponnusamy·Jinjing Qiao
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Abstract

In this paper, the main aim is to discuss the existence of the extreme points and support points of families of harmonic Bloch mappings and little harmonic Bloch mappings. First, in terms of the Bloch unit-valued set, we prove a necessary condition for a harmonic Bloch mapping (resp. a little harmonic Bloch mapping) to be an extreme point of the unit ball of the normalized harmonic Bloch spaces (resp. the normalized little harmonic Bloch spaces) in the unit disk $\mathbb{D}$. Then we show that a harmonic Bloch mapping $f$ is a support point of the unit ball of the normalized harmonic Bloch spaces in $\mathbb{D}$ if and only if the Bloch unit-valued set of $f$ is not empty. We also give a characterization for the support points of the unit ball of the harmonic Bloch spaces in $\mathbb{D}$.

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Hua Deng, Saminthan Ponnusamy, Jinjing Qiao. 2019-09-08. Extreme points and support points of families of harmonic Bloch mappings. https://arxiv.org/abs/1909.03393

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