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Some sufficient conditions on certain constants which are involved in some first, second and third order differential subordinations associated with certain functions with positive real part like modified Sigmoid function, exponential…

Complex Variables · Mathematics 2020-12-24 Meghna Sharma , Sushil Kumar , Naveen Kumar Jain

The association of subordination and special functions is used to find sharp estimates on the parameter $\beta$ such that the analytic function $p(z)$ is subordinate to certain functions having positive real part whenever $p(z)+\beta z…

Complex Variables · Mathematics 2023-08-21 Meghna Sharma , Naveen Kumar Jain , Sushil Kumar

By using the theory of first-order differential subordination for functions with fixed initial coefficient, several well-known results for subclasses of univalent functions are improved by restricting the functions to have fixed second…

Complex Variables · Mathematics 2012-08-02 Sumit Nagpal , V. Ravichandran

The primary objective of this work is to obtain some sufficient conditions so that normalized Gauss hypergeometric function satisfies exponential starlikeness and convexity in the unit disk. Moreover, conditions on parameter of this…

Complex Variables · Mathematics 2025-03-21 Anish Kumar , Sourav Das

Functions with fixed initial coefficient have been widely studied. A new methodology is proposed in this paper by making appropriate modifications and improvements to the theory of second-order differential subordination. Several…

Complex Variables · Mathematics 2012-08-02 Rosihan M. Ali , Sumit Nagpal , V. Ravichandran

We consider the class $\mathcal{S}^*(q_c)$ of normalized starlike functions $f$ analytic in the open unit disk $|z|<1$ that satisfying the inequality \begin{equation*} \left|\left(\frac{zf'(z)}{f(z)}\right)^2-1\right|<c \quad (0<c\leq1).…

Complex Variables · Mathematics 2018-07-11 R. Kargar , L. Trojnar-Spelina

In this paper, we employ a novel second and third-order differential subordination technique to establish the sufficient conditions for functions to belong to the classes $\mathcal{S}^*_s$ and $\mathcal{S}^*_{\rho}$, where $\mathcal{S}^*_s$…

Complex Variables · Mathematics 2024-03-27 Neha Verma , S. Sivaprasad Kumar

For an analytic function $f$ on the unit disk $\mathbb{D}=\{z:|z|<1\}$ satisfying $f(0)=0=f'(0)-1,$ we obtain sufficient conditions so that $f$ satisfies $|(zf'(z)/f(z))^2-1|<1.$ The technique of differential subordination of first or…

Complex Variables · Mathematics 2018-06-14 Vibha Madaan , Ajay Kumar , V. Ravichandran

Let $q_1$ and $q_2$ belong to a certain class of normalized analytic univalent functions in the open unit disk of the complex plane. Sufficient conditions are obtained for normalized analytic functions $p$ to satisfy the double…

Complex Variables · Mathematics 2011-12-30 Rosihan M. Ali , Nak Eun Cho , Oh Sang Kwon , V. Ravichandran

Let A,B,D,E belong to [-1, 1] and let p(z) be an analytic function with fixed initial coefficient defined in the open unit disk. Conditions on A,B,D,and E are determined so that 1+{\alpha}zp'(z) being subordinated to (1+Dz)/(1+Ez) implies…

Complex Variables · Mathematics 2020-05-11 Najla M. Alarifi

In this paper our aim is to present some subordination and superordination results, by using an operator, which involves the normalized form of the generalized Bessel functions of first kind. These results are obtained by investigating some…

Complex Variables · Mathematics 2016-11-26 Arpad Baricz , Erhan Deniz , Murat Caglar , Halit Orhan

Sharp estimates on $\beta$ are determined so that an analytic function $p$ defined on the open unit disk in the complex plane normalized by $p(0)=1$ is subordinate to some well known starlike functions with positive real part whenever…

Complex Variables · Mathematics 2017-03-13 O. P. Ahuja , Sushil Kumar , V. Ravichandran

The theory of first-order differential subordination developed by Miller and Mocanu was recently extended to functions with fixed initial coefficient by R. M. Ali, S. Nagpal and V. Ravichandran [Second-order differential subordination for…

Complex Variables · Mathematics 2012-12-20 Lee See Keong , V. Ravichandran , Shamani Supramaniam

Let $\mathcal{A}_n$ be the class of analytic functions $f(z)$ of the form $f(z)=z+\sum_{k=n+1}^\infty a_kz^k,n\in\mathbb{N}$ and let \begin{align*} \Omega_n:=\left\{f\in\mathcal{A}_n:\left|zf'(z)-f(z)\right|<\frac{1}{2},\;…

Complex Variables · Mathematics 2021-04-13 Lateef Ahmad Wani , A. Swaminathan

In this article, we wish to establish some first order differential subordination relations for certain Carath\'{e}odory functions with nice geometrical properties. Moreover, several implications are determined so that the normalized…

Complex Variables · Mathematics 2021-03-09 Meghna Sharma , Sushil Kumar , Naveen Kumar Jain

This paper presents several results concerning second and third-order differential subordination for the class $\mathcal{S}^{*}_{e}:=\{f\in \mathcal{A}:zf'(z)/f(z)\prec e^z\}$, which represents the class of starlike functions associated…

Complex Variables · Mathematics 2024-01-09 Neha Verma , S. Sivaprasad Kumar

We are interested in finding the sufficient conditions on $A$, $B$, $\lambda$, $b$ and $c$ which ensure that the generalized Bessel functions ${u}_{\lambda}:={u}_{\lambda,b,c}$ satisfies the subordination ${u}_{\lambda}(z) \prec (1+Az)/…

Complex Variables · Mathematics 2016-07-08 S. Kanas , S. R. Mondal , A. D. Mohammed

In the present investigation, we employ a new technique to find several first and second order differential subordination implications involving the following starlike class associated with a bean shaped domain: \begin{equation*}…

Complex Variables · Mathematics 2025-04-24 S. Sivaprasad Kumar , Pooja Yadav

In this article we study the inclusion properties of the Bessel-Struve kernel functions in the Janowski class. In particular, we find the conditions for which the Bessel-Struve kernel functions maps the unit disk to right half plane. An…

Complex Variables · Mathematics 2016-02-01 Saiful R Mondal , Mohamed Al Dhuian

Let $h$ be a non-vanishing analytic function in the open unit disc with $h(0)=1$. Consider the class consisting of normalized analytic functions $f$ whose ratios $f(z)/g(z)$, $g(z)/z p(z)$, and $p(z)$ are each subordinate to $h$ for some…

Complex Variables · Mathematics 2021-01-06 Rosihan M. Ali , Kanika Sharma , V. Ravichandran
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