Coefficient Related Studies for New Classes of Bi-Univalent Functions

Using the recently introduced Sălăgean integro-differential operator, three new classes of bi-univalent functions are introduced in this paper. In the study of bi-univalent functions, estimates on the first two Taylor–Maclaurin coefficients are usually given. We go further in the present paper and b...

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Main Authors: Ágnes Orsolya Páll-Szabó, Georgia Irina Oros
Format: Article
Language:English
Published: MDPI AG 2020-07-01
Series:Mathematics
Subjects:
Online Access:https://www.mdpi.com/2227-7390/8/7/1110
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author Ágnes Orsolya Páll-Szabó
Georgia Irina Oros
author_facet Ágnes Orsolya Páll-Szabó
Georgia Irina Oros
author_sort Ágnes Orsolya Páll-Szabó
collection DOAJ
description Using the recently introduced Sălăgean integro-differential operator, three new classes of bi-univalent functions are introduced in this paper. In the study of bi-univalent functions, estimates on the first two Taylor–Maclaurin coefficients are usually given. We go further in the present paper and bounds of the first three coefficients <inline-formula> <math display="inline"> <semantics> <mfenced separators="" open="|" close="|"> <msub> <mi>a</mi> <mn>2</mn> </msub> </mfenced> </semantics> </math> </inline-formula>, <inline-formula> <math display="inline"> <semantics> <mfenced separators="" open="|" close="|"> <msub> <mi>a</mi> <mn>3</mn> </msub> </mfenced> </semantics> </math> </inline-formula> and <inline-formula> <math display="inline"> <semantics> <mfenced separators="" open="|" close="|"> <msub> <mi>a</mi> <mn>4</mn> </msub> </mfenced> </semantics> </math> </inline-formula> of the functions in the newly defined classes are given. Obtaining Fekete–Szegő inequalities for different classes of functions is a topic of interest at this time as it will be shown later by citing recent papers. So, continuing the study on the coefficients of those classes, the well-known Fekete–Szegő functional is obtained for each of the three classes.
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spelling doaj.art-7ade27a605924629a2a332408552669b2023-11-20T05:57:24ZengMDPI AGMathematics2227-73902020-07-0187111010.3390/math8071110Coefficient Related Studies for New Classes of Bi-Univalent FunctionsÁgnes Orsolya Páll-Szabó0Georgia Irina Oros1Faculty of Mathematics and Computer Science, Babes-Bolyai University, 400084 Cluj Napoca, RomaniaDepartment of Mathematics and Computer Sciences, Faculty of Informatics and Sciences, University of Oradea, 410087 Oradea, RomaniaUsing the recently introduced Sălăgean integro-differential operator, three new classes of bi-univalent functions are introduced in this paper. In the study of bi-univalent functions, estimates on the first two Taylor–Maclaurin coefficients are usually given. We go further in the present paper and bounds of the first three coefficients <inline-formula> <math display="inline"> <semantics> <mfenced separators="" open="|" close="|"> <msub> <mi>a</mi> <mn>2</mn> </msub> </mfenced> </semantics> </math> </inline-formula>, <inline-formula> <math display="inline"> <semantics> <mfenced separators="" open="|" close="|"> <msub> <mi>a</mi> <mn>3</mn> </msub> </mfenced> </semantics> </math> </inline-formula> and <inline-formula> <math display="inline"> <semantics> <mfenced separators="" open="|" close="|"> <msub> <mi>a</mi> <mn>4</mn> </msub> </mfenced> </semantics> </math> </inline-formula> of the functions in the newly defined classes are given. Obtaining Fekete–Szegő inequalities for different classes of functions is a topic of interest at this time as it will be shown later by citing recent papers. So, continuing the study on the coefficients of those classes, the well-known Fekete–Szegő functional is obtained for each of the three classes.https://www.mdpi.com/2227-7390/8/7/1110bi-univalent functionsSălăgean integral and differential operatorcoefficient boundsFekete–Szegő problem
spellingShingle Ágnes Orsolya Páll-Szabó
Georgia Irina Oros
Coefficient Related Studies for New Classes of Bi-Univalent Functions
Mathematics
bi-univalent functions
Sălăgean integral and differential operator
coefficient bounds
Fekete–Szegő problem
title Coefficient Related Studies for New Classes of Bi-Univalent Functions
title_full Coefficient Related Studies for New Classes of Bi-Univalent Functions
title_fullStr Coefficient Related Studies for New Classes of Bi-Univalent Functions
title_full_unstemmed Coefficient Related Studies for New Classes of Bi-Univalent Functions
title_short Coefficient Related Studies for New Classes of Bi-Univalent Functions
title_sort coefficient related studies for new classes of bi univalent functions
topic bi-univalent functions
Sălăgean integral and differential operator
coefficient bounds
Fekete–Szegő problem
url https://www.mdpi.com/2227-7390/8/7/1110
work_keys_str_mv AT agnesorsolyapallszabo coefficientrelatedstudiesfornewclassesofbiunivalentfunctions
AT georgiairinaoros coefficientrelatedstudiesfornewclassesofbiunivalentfunctions