English

Order of convexity of Integral Transforms and Duality

Complex Variables 2013-05-06 v1

Abstract

Recently, Ali et al defined the class Wβ(α,γ)\mathcal{W}_{\beta}(\alpha, \gamma) consisting of functions ff which satisfy eiϕ((1α+2γ)f(z)z+(α2γ)f(z)+γzf(z)β)>0,\Re e^{i\phi}\left((1-\alpha+2\gamma)\frac{f(z)}{z}+(\alpha-2\gamma)f'(z)+\gamma zf''(z)-\beta\right)>0, for all zE={z:z<1}z\in E=\left\{z : |z|<1\right\} and for α,γ0\alpha, \gamma\geq0 and β<1\beta<1, ϕR\phi\in \mathbb{R} (the set of reals). For fWβ(α,γ)f\in{\mathcal{W}_{\beta}(\alpha, \gamma)}, they discussed the convexity of the integral transform Vλ(f)(z):=01λ(t)f(tz)tdt,V_{\lambda}(f)(z):=\int_{0}^{1}\lambda(t)\frac{f(tz)}{t}dt, where λ\lambda is a non-negative real-valued integrable function satisfying the condition 01λ(t)dt=1\displaystyle\int_{0}^{1}\lambda(t)dt=1. The aim of present paper is to find conditions on λ(t)\lambda(t) such that Vλ(f)V_{\lambda}(f) is convex of order δ\delta (0δ1/20\leq\delta\leq1/2) whenever fWβ(α,γ)f\in{\mathcal{W}}_{\beta}(\alpha, \gamma). As applications, we study various choices of λ(t)\lambda(t), related to classical integral transforms.

Keywords

Cite

@article{arxiv.1305.0732,
  title  = {Order of convexity of Integral Transforms and Duality},
  author = {Sarika Verma and Sushma Gupta and Sukhjit Singh},
  journal= {arXiv preprint arXiv:1305.0732},
  year   = {2013}
}

Comments

15 pages