English

Integral transforms of functions to be in the Pascu class using duality techniques

Complex Variables 2014-11-24 v1

Abstract

Let Wβ(α,γ)W_{\beta}(\alpha,\gamma), β<1\beta<1, denote the class of all normalized analytic functions ff in the unit disc D={zC:z<1}{\mathbb{D}}=\{z\in {\mathbb{C}}: |z|<1\} such that \begin{align*} {\rm Re\,} \left(e^{i\phi}\left((1-\alpha+2\gamma)\frac{f}{z}+(\alpha-2\gamma)f'+\gamma zf"-\beta\right)\frac{}{}\right)>0, \quad z\in {\mathbb{D}}, \end{align*} for some ϕR\phi\in {\mathbb{R}} with α0\alpha\geq 0, γ0\gamma\geq 0 and β<1\beta< 1. Let M(ξ)M(\xi), 0ξ10\leq \xi\leq 1, denote the Pascu class of ξ\xi-convex functions given by the analytic condition \begin{align*} {\rm Re\,}\frac{\xi z(zf'(z))'+(1-\xi)zf'(z)}{\xi zf'(z)+(1-\xi)f(z)}>0 \end{align*} which unifies the class of starlike and convex functions. The aim of this paper is to find conditions on λ(t)\lambda(t) so that the integral transforms of the form \begin{align*} V_{\lambda}(f)(z)= \int_0^1 \lambda(t) \frac{f(tz)}{t} dt. \end{align*} carry functions from Wβ(α,γ)W_{\beta}(\alpha,\gamma) into M(ξ)M(\xi). As applications, for specific values of λ(t)\lambda(t), it is found that several known integral operators carry functions from Wβ(α,γ)W_{\beta}(\alpha,\gamma) into M(ξ)M(\xi). Results for a more generalized operator related to Vλ(f)(z)V_\lambda(f)(z) are also given.

Keywords

Cite

@article{arxiv.1304.0696,
  title  = {Integral transforms of functions to be in the Pascu class using duality techniques},
  author = {Satwanti Devi and A. Swaminathan},
  journal= {arXiv preprint arXiv:1304.0696},
  year   = {2014}
}

Comments

17 pages

R2 v1 2026-06-21T23:52:22.073Z