Sharp initial coefficient bounds and the Fekete–Szegö problem for some certain subclasses of analytic and bi-univalent functions

UDC 517.5 We introduce two new subclasses $\mathcal{U}_{\Sigma}(\alpha,\lambda)$ and ${\mathcal{B}_1}_{\Sigma}(\alpha)$ of analytic bi-univalent functions defined in the open unit disk $\mathbb{U}$, which are associated with the Bazilevich functions.  In addition, for funct...

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Дата:2023
Автори: Patil, A. B., Shaba, T. G.
Формат: Стаття
Мова:Англійська
Опубліковано: Institute of Mathematics, NAS of Ukraine 2023
Онлайн доступ:https://umj.imath.kiev.ua/index.php/umj/article/view/6602
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Назва журналу:Ukrains’kyi Matematychnyi Zhurnal
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Ukrains’kyi Matematychnyi Zhurnal
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author Patil, A. B.
Shaba, T. G.
Patil, A. B.
Shaba, T. G.
author_facet Patil, A. B.
Shaba, T. G.
Patil, A. B.
Shaba, T. G.
author_sort Patil, A. B.
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datestamp_date 2023-03-06T14:26:58Z
description UDC 517.5 We introduce two new subclasses $\mathcal{U}_{\Sigma}(\alpha,\lambda)$ and ${\mathcal{B}_1}_{\Sigma}(\alpha)$ of analytic bi-univalent functions defined in the open unit disk $\mathbb{U}$, which are associated with the Bazilevich functions.  In addition, for functions that belong to these subclasses, we obtain sharp bounds for the initial Taylor–Maclaurin coefficients $a_2$ and $a_3,$ as well as the sharp estimate for the Fekete–Szegö functional $a_3-\mu a_2^2.$
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spelling umjimathkievua-article-66022023-03-06T14:26:58Z Sharp initial coefficient bounds and the Fekete–Szegö problem for some certain subclasses of analytic and bi-univalent functions Sharp initial coefficient bounds and the Fekete–Szegö problem for some certain subclasses of analytic and bi-univalent functions Patil, A. B. Shaba, T. G. Patil, A. B. Shaba, T. G. Analytic function Univalent function Bi-univalent function Starlike function Bazilevic function Fekete-Szego functional Mathematics Analysis UDC 517.5 We introduce two new subclasses $\mathcal{U}_{\Sigma}(\alpha,\lambda)$ and ${\mathcal{B}_1}_{\Sigma}(\alpha)$ of analytic bi-univalent functions defined in the open unit disk $\mathbb{U}$, which are associated with the Bazilevich functions.  In addition, for functions that belong to these subclasses, we obtain sharp bounds for the initial Taylor–Maclaurin coefficients $a_2$ and $a_3,$ as well as the sharp estimate for the Fekete–Szegö functional $a_3-\mu a_2^2.$ УДК 517.5 Точні початкові коефіцієнтні межі та задача  Фекета–Сега для деяких підкласів аналітичних та біодновалентних функцій Введено два нових підкласи $\mathcal{U}_{\Sigma}(\alpha,\lambda)$ і ${\mathcal{B}_1}_{\Sigma}(\alpha)$ аналітичниx біодновалентних функцій, що визначені у відкритому одиничному крузі $\mathbb{U}$ та асоціюються з функціями Базилевича.  Крім того, для функцій, що належать до цих підкласів,  отримано точні межі для початкових коефіцієнтів Тейлора–Маклорена $a_2$ і $a_3$, а також точну оцінку функціонала Фекетa–Сега $a_3-\mu a_2 ^2.$ Institute of Mathematics, NAS of Ukraine 2023-03-02 Article Article https://umj.imath.kiev.ua/index.php/umj/article/view/6602 10.37863/umzh.v75i2.6602 Ukrains’kyi Matematychnyi Zhurnal; Vol. 75 No. 2 (2023); 198 - 206 Український математичний журнал; Том 75 № 2 (2023); 198 - 206 1027-3190 en https://umj.imath.kiev.ua/index.php/umj/article/view/6602/9795 Copyright (c) 2023 Amol Patil, Timilehin Shaba
spellingShingle Patil, A. B.
Shaba, T. G.
Patil, A. B.
Shaba, T. G.
Sharp initial coefficient bounds and the Fekete–Szegö problem for some certain subclasses of analytic and bi-univalent functions
title Sharp initial coefficient bounds and the Fekete–Szegö problem for some certain subclasses of analytic and bi-univalent functions
title_alt Sharp initial coefficient bounds and the Fekete–Szegö problem for some certain subclasses of analytic and bi-univalent functions
title_full Sharp initial coefficient bounds and the Fekete–Szegö problem for some certain subclasses of analytic and bi-univalent functions
title_fullStr Sharp initial coefficient bounds and the Fekete–Szegö problem for some certain subclasses of analytic and bi-univalent functions
title_full_unstemmed Sharp initial coefficient bounds and the Fekete–Szegö problem for some certain subclasses of analytic and bi-univalent functions
title_short Sharp initial coefficient bounds and the Fekete–Szegö problem for some certain subclasses of analytic and bi-univalent functions
title_sort sharp initial coefficient bounds and the fekete–szegö problem for some certain subclasses of analytic and bi-univalent functions
topic_facet Analytic function
Univalent function
Bi-univalent function
Starlike function
Bazilevic function
Fekete-Szego functional
Mathematics
Analysis
url https://umj.imath.kiev.ua/index.php/umj/article/view/6602
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