{"title":"A Conjecture on <i>H</i> <sub>3</sub>(1) for Certain Starlike Functions","authors":"Neha Verma, S. Sivaprasad Kumar","doi":"10.1515/ms-2023-0088","DOIUrl":null,"url":null,"abstract":"ABSTRACT We prove a conjecture concerning the third Hankel determinant, proposed by Kumar and Kamaljeet in [A cardioid domain and starlike functions , Anal. Math. Phys. 11 (2021), Art. 54], which states that | H 3 (1)| ≤ 1/9 is sharp for the class <m:math xmlns:m=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"> <m:msubsup> <m:mi mathvariant=\"script\">S</m:mi> <m:mi>℘</m:mi> <m:mo>*</m:mo> </m:msubsup> <m:mo>=</m:mo> <m:mrow> <m:mo>{</m:mo> <m:mrow> <m:mi>z</m:mi> <m:msup> <m:mi>f</m:mi> <m:mo>′</m:mo> </m:msup> <m:mrow> <m:mo>(</m:mo> <m:mi>z</m:mi> <m:mo>)</m:mo> </m:mrow> <m:mtext>/</m:mtext> <m:mi>f</m:mi> <m:mrow> <m:mo>(</m:mo> <m:mi>z</m:mi> <m:mo>)</m:mo> </m:mrow> <m:mo>≺</m:mo> <m:mi>φ</m:mi> <m:mrow> <m:mo>(</m:mo> <m:mi>z</m:mi> <m:mo>)</m:mo> </m:mrow> <m:mo>:</m:mo> <m:mo>=</m:mo> <m:mn>1</m:mn> <m:mo>+</m:mo> <m:mi>z</m:mi> <m:msup> <m:mi>e</m:mi> <m:mi>z</m:mi> </m:msup> </m:mrow> <m:mo>}</m:mo> </m:mrow> </m:math> . In addition, we also establish bounds for sixth and seventh coefficient, and | H 4 (1)| for functions in <m:math xmlns:m=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"> <m:msubsup> <m:mi mathvariant=\"script\">S</m:mi> <m:mi>℘</m:mi> <m:mo>*</m:mo> </m:msubsup> </m:math> . The general bounds for two and three folds symmteric functions related with the Ma-Minda classes <m:math xmlns:m=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"> <m:msup> <m:mi mathvariant=\"script\">S</m:mi> <m:mo>*</m:mo> </m:msup> <m:mrow> <m:mo>(</m:mo> <m:mi>φ</m:mi> <m:mo>)</m:mo> </m:mrow> </m:math> of starlike functions are also obtained.","PeriodicalId":0,"journal":{"name":"","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"3","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1515/ms-2023-0088","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 3
Abstract
ABSTRACT We prove a conjecture concerning the third Hankel determinant, proposed by Kumar and Kamaljeet in [A cardioid domain and starlike functions , Anal. Math. Phys. 11 (2021), Art. 54], which states that | H 3 (1)| ≤ 1/9 is sharp for the class S℘*={zf′(z)/f(z)≺φ(z):=1+zez} . In addition, we also establish bounds for sixth and seventh coefficient, and | H 4 (1)| for functions in S℘* . The general bounds for two and three folds symmteric functions related with the Ma-Minda classes S*(φ) of starlike functions are also obtained.