Journal of Inequalities and Applications
Volume 2008 (2008), Article ID 346279, 9 pages
doi:10.1155/2008/346279
Research Article
Neighborhoods of Starlike and Convex Functions Associated with Parabola
1School of Mathematical Sciences, Universiti Sains Malaysia, Penang 11800, Malaysia
2Department of Mathematics, University of Delhi, Delhi 110007, India
3Department of Mathematics, Kent State University, Burton, OH 44021-9500, USA
Received 16 June 2008; Accepted 11 August 2008
Academic Editor: Ramm Mohapatra
Copyright © 2008 Rosihan M. Ali et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
Let f be a normalized analytic function defined on the unit disk and fλ(z):=(1−λ)z+λf(z) for 0<λ≤1. For α>0, a function f∈𝒮𝒫(α,λ) if zf′(z)/fλ(z) lies in the parabolic region Ω:={w:|w−α|<Re w+α}. Let 𝒞𝒫(α,λ) be the corresponding class consisting of functions f such that (zf′(z))′/fλ′(z) lies in the region Ω. For an appropriate δ>0, the δ-neighbourhood of a function f∈𝒞𝒫(α,λ) is shown to consist of functions in the class 𝒮𝒫(α,λ).