Browsing by Author "Ravichandran, V"

Now showing 1 - 6 of 6
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    Applications of first order differential subordination for functions with positive real part
    (Babes-Bolyai University, 2018-09-26) Ahuja, Om P.; Kumar, Sushil; Ravichandran, V
    Several inclusions between the class of functions with positive real part and the class of starlike univalent functions associated with lemniscate of Bernoulli are obtained by making use of the well-known theory of differential subordination. Further, these inclusions give sufficient conditions for normalized analytic functions to belong to some subclasses of starlike functions. The results also provide sharp version of some previously known results.
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    Differential subordination for Janowski functions with positive real part
    (Babes-Bolyai University, 2021-09-28) Anand, Swati; Kumar, Sushil; Ravichandran, V
    Theory of differential subordination provides techniques to reduce differential subordination problems into verifying some simple algebraic condition called admissibility condition. We exploit the first order differential subordination theory to get several sufficient conditions for function satisfying several differential subordinations to be a Janowski function with positive real part. As applications, we obtain sufficient conditions for normalized analytic functions to be Janowski starlike functions.
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    Ma-Minda starlikeness of certain analytic functions
    (Babes-Bolyai University, 2025-02-25) Janani, Baskar Babujee; Ravichandran, V
    A normałized anałytic function defined on the open unit disc (Formula presented) is całłed Ma-Minda starłike if zf0(z)/f(z) is subordinate to the function ϕ. For a normałized convex function f defined on (Formula presented) and α > 0, we determine the radius of Ma-Minda starłikeness of the function g defined as (Formula presented) for certain choices of ϕ. In particułar, we investigate the radius of Janowski starłikeness of the function g. © Studia UBB MATHEMATICA. Published by Babeş-Bolyai University This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
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    Sharp Bounds on the Higher Order Schwarzian Derivatives for Janowski Classes
    (MDPI AG, 2018-08-18) Cho, Nak Eun; Kumar, Virendra; Ravichandran, V
    Higher order Schwarzian derivatives for normalized univalent functions were first considered by Schippers, and those of convex functions were considered by Dorff and Szynal. In the present investigation, higher order Schwarzian derivatives for the Janowski star-like and convex functions are considered, and sharp bounds for the first three consecutive derivatives are investigated. The results obtained in this paper generalize several existing results in this direction.
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    Star-likeness associated with the exponential function
    (TUBITAK, 2019-03-22) Naz, Adiba; Nagpal, Sumit; Ravichandran, V
    Given a domain Ω in the complex plane and a univalent function q defined in an open unit disk D[double-struck] with nice boundary behaviour, Miller and Mocanu studied the class of admissible functions Ψ(Ω, q) so that the differential subordination Ψ (p(z), zp'(z), z2p''(z); z) ≺ h(z) implies p(z) ≺ q(z), where p is an analytic function in D[double-struck] with p(0) = 1, ψ: 3 ×D[double-struck] → and Ω = h(D[double-struck]) . This paper investigates the properties of this class for q(z) = ez . As application, several sufficient conditions for normalized analytic functions f to be in the subclass of star-like functions associated with the exponential function are obtained.
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    Starlike functions related to the bell numbers
    (MDPI AG, 2019-02-13) Cho, Nak Eun; Kumar, Sushil; Kumar, Virendra; Ravichandran, V; Srivastava, H. M.
    The present paper aims to establish the first order differential subordination relations between functions with a positive real part and starlike functions related to the Bell numbers. In addition, several sharp radii estimates for functions in the class of starlike functions associated with the Bell numbers are determined. © 2019 by the authors.