Bi-Starlike Function of Complex Order Involving Mathieu-Type Series in the Shell-Shaped Region

For functions of the form <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>ϕ</mi><mrow><mo>(</mo><mi>ξ</mi><mo>)</mo></mrow><mo>=</mo...

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Main Authors: Ibrahim S. Elshazly, Gangadharan Murugusundaramoorthy, Borhen Halouani, Alaa H. El-Qadeem, Kaliappan Vijaya
Format: Article
Language:English
Published: MDPI AG 2024-10-01
Series:Axioms
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Online Access:https://www.mdpi.com/2075-1680/13/11/747
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author Ibrahim S. Elshazly
Gangadharan Murugusundaramoorthy
Borhen Halouani
Alaa H. El-Qadeem
Kaliappan Vijaya
author_facet Ibrahim S. Elshazly
Gangadharan Murugusundaramoorthy
Borhen Halouani
Alaa H. El-Qadeem
Kaliappan Vijaya
author_sort Ibrahim S. Elshazly
collection DOAJ
description For functions of the form <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>ϕ</mi><mrow><mo>(</mo><mi>ξ</mi><mo>)</mo></mrow><mo>=</mo><mi>ξ</mi><mo>+</mo><msubsup><mo>∑</mo><mrow><mi>n</mi><mo>=</mo><mn>2</mn></mrow><mo>∞</mo></msubsup><msub><mi>c</mi><mi>n</mi></msub><msup><mi>ξ</mi><mi>n</mi></msup></mrow></semantics></math></inline-formula>, we identified two new subclasses of bi-starlike functions and bi-convex functions by using Mathieu-type series defined in the disc <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>Δ</mo><mo>=</mo><mo>{</mo><mi>ξ</mi><mo>∈</mo><mi mathvariant="double-struck">C</mi><mo>:</mo><mo>|</mo><mi>ξ</mi><mo>|</mo><mo><</mo><mn>1</mn><mo>}</mo></mrow></semantics></math></inline-formula>. We derived constraints for <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mrow><mo>|</mo></mrow><msub><mi>c</mi><mn>2</mn></msub><mrow><mo>|</mo></mrow></mrow></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mrow><mo>|</mo></mrow><msub><mi>c</mi><mn>3</mn></msub><mrow><mo>|</mo></mrow></mrow></semantics></math></inline-formula>, and the subclasses are connected to the shell-shaped area. The Fekete–Szegö functional properties for the aforementioned function subclasses were also investigated. Additionally, a number of related corollaries are shown.
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spelling doaj-art-8a7739dcea2a438e80b74a9f4ef14a202025-08-20T01:53:40ZengMDPI AGAxioms2075-16802024-10-01131174710.3390/axioms13110747Bi-Starlike Function of Complex Order Involving Mathieu-Type Series in the Shell-Shaped RegionIbrahim S. Elshazly0Gangadharan Murugusundaramoorthy1Borhen Halouani2Alaa H. El-Qadeem3Kaliappan Vijaya4Department of Basic Sciences, Common First Year Deanship, King Saud University, Riyadh 11451, Saudi ArabiaSchool of Advanced Sciences, Vellore Institute of Technology, Vellore 632014, IndiaDepartment of Mathematics, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi ArabiaDepartment of Mathematics, Faculty of Science, Zagazig University, Zagazig 44519, EgyptSchool of Advanced Sciences, Vellore Institute of Technology, Vellore 632014, IndiaFor functions of the form <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>ϕ</mi><mrow><mo>(</mo><mi>ξ</mi><mo>)</mo></mrow><mo>=</mo><mi>ξ</mi><mo>+</mo><msubsup><mo>∑</mo><mrow><mi>n</mi><mo>=</mo><mn>2</mn></mrow><mo>∞</mo></msubsup><msub><mi>c</mi><mi>n</mi></msub><msup><mi>ξ</mi><mi>n</mi></msup></mrow></semantics></math></inline-formula>, we identified two new subclasses of bi-starlike functions and bi-convex functions by using Mathieu-type series defined in the disc <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>Δ</mo><mo>=</mo><mo>{</mo><mi>ξ</mi><mo>∈</mo><mi mathvariant="double-struck">C</mi><mo>:</mo><mo>|</mo><mi>ξ</mi><mo>|</mo><mo><</mo><mn>1</mn><mo>}</mo></mrow></semantics></math></inline-formula>. We derived constraints for <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mrow><mo>|</mo></mrow><msub><mi>c</mi><mn>2</mn></msub><mrow><mo>|</mo></mrow></mrow></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mrow><mo>|</mo></mrow><msub><mi>c</mi><mn>3</mn></msub><mrow><mo>|</mo></mrow></mrow></semantics></math></inline-formula>, and the subclasses are connected to the shell-shaped area. The Fekete–Szegö functional properties for the aforementioned function subclasses were also investigated. Additionally, a number of related corollaries are shown.https://www.mdpi.com/2075-1680/13/11/747bi-univalentanalyticbi-convexbi-starlikecoefficients bounds
spellingShingle Ibrahim S. Elshazly
Gangadharan Murugusundaramoorthy
Borhen Halouani
Alaa H. El-Qadeem
Kaliappan Vijaya
Bi-Starlike Function of Complex Order Involving Mathieu-Type Series in the Shell-Shaped Region
Axioms
bi-univalent
analytic
bi-convex
bi-starlike
coefficients bounds
title Bi-Starlike Function of Complex Order Involving Mathieu-Type Series in the Shell-Shaped Region
title_full Bi-Starlike Function of Complex Order Involving Mathieu-Type Series in the Shell-Shaped Region
title_fullStr Bi-Starlike Function of Complex Order Involving Mathieu-Type Series in the Shell-Shaped Region
title_full_unstemmed Bi-Starlike Function of Complex Order Involving Mathieu-Type Series in the Shell-Shaped Region
title_short Bi-Starlike Function of Complex Order Involving Mathieu-Type Series in the Shell-Shaped Region
title_sort bi starlike function of complex order involving mathieu type series in the shell shaped region
topic bi-univalent
analytic
bi-convex
bi-starlike
coefficients bounds
url https://www.mdpi.com/2075-1680/13/11/747
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