A class of gap series with small growth in the unit disc

Let β>0 and let α be an integer which is at least 2. If f is an analytic function in the unit disc D which has power series representation f(z)=∑k=0∞ak zkα, limsupk→∞ (log+|ak|/logk)=α(1+β), then the first author has proved that f is unbounded in every sector {z∈D:Φ−ϵ<argz<Φ+ϵ, for ϵ>0}....

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Main Authors: L. R. Sons, Zhuan Ye
Format: Article
Language:English
Published: Wiley 2002-01-01
Series:International Journal of Mathematics and Mathematical Sciences
Online Access:http://dx.doi.org/10.1155/S0161171202111136
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author L. R. Sons
Zhuan Ye
author_facet L. R. Sons
Zhuan Ye
author_sort L. R. Sons
collection DOAJ
description Let β>0 and let α be an integer which is at least 2. If f is an analytic function in the unit disc D which has power series representation f(z)=∑k=0∞ak zkα, limsupk→∞ (log+|ak|/logk)=α(1+β), then the first author has proved that f is unbounded in every sector {z∈D:Φ−ϵ<argz<Φ+ϵ, for ϵ>0}. A natural conjecture concerning these functions is that limsupr→1−(logL(r)/logM(r))>0, where L(r) is the minimum of |f(z)| on |z|=r and M(r) is the maximum of |f(z)| on |z|=r. In this paper, investigations concerning this conjecture are discussed. For example, we prove that limsupr→1−(logL(r)/logM(r))=1 and limsupr→1−(L(r)/M(r))=0 when ak=kα(1+β).
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spelling doaj-art-dd1c5119cb1b4fc1985b3e196ec8206a2025-02-03T01:22:55ZengWileyInternational Journal of Mathematics and Mathematical Sciences0161-17121687-04252002-01-01321294010.1155/S0161171202111136A class of gap series with small growth in the unit discL. R. Sons0Zhuan Ye1Department of Mathematical Sciences, Northern Illinois University, DeKalb 60115, IL, USADepartment of Mathematical Sciences, Northern Illinois University, DeKalb 60115, IL, USALet β>0 and let α be an integer which is at least 2. If f is an analytic function in the unit disc D which has power series representation f(z)=∑k=0∞ak zkα, limsupk→∞ (log+|ak|/logk)=α(1+β), then the first author has proved that f is unbounded in every sector {z∈D:Φ−ϵ<argz<Φ+ϵ, for ϵ>0}. A natural conjecture concerning these functions is that limsupr→1−(logL(r)/logM(r))>0, where L(r) is the minimum of |f(z)| on |z|=r and M(r) is the maximum of |f(z)| on |z|=r. In this paper, investigations concerning this conjecture are discussed. For example, we prove that limsupr→1−(logL(r)/logM(r))=1 and limsupr→1−(L(r)/M(r))=0 when ak=kα(1+β).http://dx.doi.org/10.1155/S0161171202111136
spellingShingle L. R. Sons
Zhuan Ye
A class of gap series with small growth in the unit disc
International Journal of Mathematics and Mathematical Sciences
title A class of gap series with small growth in the unit disc
title_full A class of gap series with small growth in the unit disc
title_fullStr A class of gap series with small growth in the unit disc
title_full_unstemmed A class of gap series with small growth in the unit disc
title_short A class of gap series with small growth in the unit disc
title_sort class of gap series with small growth in the unit disc
url http://dx.doi.org/10.1155/S0161171202111136
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