English

Schwarzian norm estimates for some classes of analytic functions

Complex Variables 2022-12-14 v1

Abstract

Let A\mathcal{A} denote the class of analytic functions ff in the unit disk D={zC:z<1}\mathbb{D}=\{z\in\mathbb{C}:|z|<1\} normalized by f(0)=0f(0)=0, f(0)=1f'(0)=1. In the present article, we obtain the sharp estimates of the Schwarzian norm for functions in the classes G(β)={fA:Re[1+zf(z)/f(z)]<1+β/2}\mathcal{G}(\beta)=\{f\in \mathcal{A}:{\rm Re\,}[1+zf''(z)/f'(z)]<1+\beta/2\}, where β>0\beta>0 and F(α)={fA:Re[1+zf(z)/f(z)]>α}\mathcal{F}(\alpha)=\{f\in \mathcal{A}:{\rm Re\,}[1+zf''(z)/f'(z)]>\alpha\}, where 1/2α0-1/2\le \alpha\le 0. We also establish two-point distortion theorem for functions in the classes G(β)\mathcal{G}(\beta) and F(α)\mathcal{F}(\alpha).

Keywords

Cite

@article{arxiv.2212.06374,
  title  = {Schwarzian norm estimates for some classes of analytic functions},
  author = {Md Firoz Ali and Sanjit Pal},
  journal= {arXiv preprint arXiv:2212.06374},
  year   = {2022}
}
R2 v1 2026-06-28T07:31:59.255Z