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This paper explores the asymptotic behaviour of the radii of convexity and uniform convexity for normalized Bessel functions with respect to large order. We provide detailed asymptotic expansions for these radii and establish recurrence…

Complex Variables · Mathematics 2025-10-17 Árpád Baricz , Pranav Kumar , Sanjeev Singh

In this paper, we determine the radius of uniform convexity for three kinds of normalized Bessel functions of the first kind. In the mentioned cases the normalized Bessel functions are uniformly convex on the determined disks. Moreover,…

Complex Variables · Mathematics 2017-04-03 Erhan Deniz , Róbert Szász

The radius of convexity of two normalized Bessel functions of the first kind are determined in the case when the order is between $-2$ and $-1.$ Our methods include the minimum principle for harmonic functions, the Hadamard factorization of…

Classical Analysis and ODEs · Mathematics 2016-01-11 Árpád Baricz , Róbert Szász

Tight lower and upper bounds for the radius of univalence of some normalized Bessel, Struve and Lommel functions of the first kind are obtained via Euler-Rayleigh inequalities. It is shown also that the radius of univalence of the Struve…

Classical Analysis and ODEs · Mathematics 2017-07-14 Ibrahim Aktaş , Árpád Baricz , Nihat Yağmur

In this note our aim is to deduce some new monotonicity properties for a special combination of Bessel functions of the first kind by using a recently developed Mittag-Leffler expansion for the derivative of a normalized Bessel function of…

Classical Analysis and ODEs · Mathematics 2016-11-17 Árpád Baricz , Tibor K. Pogány , Róbert Szász

The main purpose of the present paper is to ascertain the radii of starlikeness and convexity associated with lemniscate of Bernoulli and the Janowski function, $(1+Az)/(1+Bz)$ for $-1\leq B<A\leq 1,$ of normalized hyper-Bessel function.

Complex Variables · Mathematics 2019-11-20 Evrim Toklu , Osman Kara

In this paper our aim is to investigate the radii of $\eta-$uniformly convexity, $\alpha-$convexity, $\eta-$parabolic starlikeness and strong starlikeness of order $\rho$ of the generalized Mittag-Leffler function for three different kinds…

Complex Variables · Mathematics 2020-09-16 Anuja Prajapati

For a fixed $a \in \{1, 2, 3, \ldots\},$ the radius of starlikeness of positive order is obtained for each of the normalized analytic functions \begin{align*} \mathtt{f}_{a, \nu}(z)&:= \bigg(2^{a \nu-a+1} a^{-\frac{a(a\nu-a+1)}{2}} \Gamma(a…

Complex Variables · Mathematics 2017-07-04 Rosihan M. Ali , See Keong Lee , Saiful R. Mondal

In the present investigation, by applying two different normalizations of the Jackson and Hahn-Exton $q$-Bessel functions tight lower and upper bounds for the radii of convexity of the same functions are obtained. In addition, it was shown…

Complex Variables · Mathematics 2017-02-16 Halit Orhan , İbrahim Aktaş

In this investigation our main aim is to determine the radius of uniform convexity of the some normalized q-Bessel and Wright functions. Here we consider six different normalized forms of q-Bessel functions, while we apply three different…

Complex Variables · Mathematics 2019-06-27 İbrahim Aktaş , Evrim Toklu , Halit Orhan

Geometric properties of the classical Lommel and Struve functions, both of the first kind, are studied. For each of them, there different normalizations are applied in such a way that the resulting functions are analytic in the unit disc of…

Classical Analysis and ODEs · Mathematics 2017-07-14 Árpád Baricz , Dimitar K. Dimitrov , Halit Orhan , Nihat Yagmur

In this paper a necessary and sufficient condition is deduced for the close-to-convexity of a cross product of Bessel and modified Bessel functions of the first kind and their derivatives by using a result of Shah and Trimble about…

Classical Analysis and ODEs · Mathematics 2017-07-14 Huda A. Al-Kharsani , Árpád Baricz , Tibor K. Pogány

In this paper necessary and sufficient conditions are deduced for the close-to-convexity of some special combinations of Bessel functions of the first kind and their derivatives by using a result of Shah and Trimble about transcendental…

Classical Analysis and ODEs · Mathematics 2017-07-14 Árpad Baricz , Erhan Deniz , Nihat Yagmur

The radii of convexity of some Lommel and Struve functions of the first kind are determined. For both of Lommel and Struve functions three different normalizations are applied in such a way that the resulting functions are analytic in the…

Classical Analysis and ODEs · Mathematics 2017-07-14 Árpád Baricz , Nihat Yağmur

The goal of this paper is to extend the classical and multiplicative fractional derivatives. For this purpose, it is introduced the new extended modified Bessel function and also given an important relation between this new function…

Classical Analysis and ODEs · Mathematics 2017-03-14 Ali Ozyapici , Yusuf Gurefe , Emine Missirli

The main purpose of the present paper is to determine the radii of starlikeness and convexity associated with lemniscate of Bernoulli and the Janowski function, $(1+Az)/(1+Bz)$ for $-1\leq B<A\leq 1,$ of normalized Wright functions. The key…

Complex Variables · Mathematics 2020-04-07 Evrim Toklu , Neslihan Karagöz

The purpose of this paper is twofold. One is to investigate the properties of the zeros of cross-products of Bessel functions or derivatives of ultraspherical Bessel functions, as well as the properties of the zeros of the derivative of the…

Classical Analysis and ODEs · Mathematics 2024-12-19 Jingwei Guo , Tao Jiang , Zuoqin Wang , Xuerui Yang

In this paper, we deal with some geometric properties including starlikeness and convexity of order $\alpha$ of Jackson's second and third $q$-Bessel functions which are natural extensions of classical Bessel function $J_{\nu}$. In additon,…

Complex Variables · Mathematics 2019-09-09 İbrahim Aktaş

In this paper, four parameters Wright function is considered. Certain geometric properties such as starlikeness, convexity, uniform convexity and close-to-convexity are discussed for this function. Further, certain geometric properties of…

Complex Variables · Mathematics 2021-07-13 Sourav Das , Khaled Mehrez

Sufficient conditions are determined on the parameters such that the generalized and normalized Bessel function of the first kind and other related functions belong to subclasses of starlike and convex functions defined in the unit disk…

Complex Variables · Mathematics 2021-01-18 Adiba Naz , Sumit Nagpal , V. Ravichandran