$q$--Rabotnov Functions and Bi-univalent Functions
DOI:
https://doi.org/10.29020/nybg.ejpam.v19i1.7109Keywords:
Subordination, ultraspherical Polynomial, $\q$-Calculus, analytic functions,, univalent functions, bi-univalent functions, orthogonal polynomials, carathéodory's functions, fekete-Szeg\"{o} problemAbstract
In this work, we introduce and investigate a new subclass of bi-univalent functions, denoted by $\mathfrak{R}_{\Sigma}^{\mu,x}(\varrho,\varphi,\lambda;\gamma;q)$, which is defined through the interplay between $q$--Rabotnov functions and $q$--Gegenbauer polynomials. For functions in this class, we derive sharp bounds for the initial Taylor--Maclaurin coefficients $|a_{2}|$ and $|a_{3}|$, and we establish estimates for the corresponding Fekete--Szeg\H{o} functional. Furthermore, by selecting suitable parameter values, our results reduce to several well known subclasses, thereby yielding a range of new consequences and extensions in the theory of analytic bi-univalent functions.
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Copyright (c) 2026 Abdullah Alsoboh, Ala Amourah, Omar Alnajar, Fahad Al Abri, Tala Sasa

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