Some inequalities for rational function with prescribed poles and restricted zeros

In this article, we first prove some auxiliary results in the form of lemmas using an improved Schwarz lemma at the boundary recently proved by Mercer. Furthermore, we establish some new inequalities for rational functions on the unit disk in the complex plane with prescribed poles and restricted ze...

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Bibliographic Details
Main Authors: Soraisam Robinson, Devi Khangembam Babina, Chanam Barchand
Format: Article
Language:English
Published: De Gruyter 2025-02-01
Series:Demonstratio Mathematica
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Online Access:https://doi.org/10.1515/dema-2025-0102
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Summary:In this article, we first prove some auxiliary results in the form of lemmas using an improved Schwarz lemma at the boundary recently proved by Mercer. Furthermore, we establish some new inequalities for rational functions on the unit disk in the complex plane with prescribed poles and restricted zeros. It is of interest to know that in the bounds of theorems we prove, four extremal coefficients of the numerator polynomial are incorporated rather than usually two coefficients in the existing literature. Moreover, our results strengthen some recent results concerning the inequalities for rational functions and, in turn, produce refinements of some polynomial inequalities as particular cases.
ISSN:2391-4661