The Bohr inequality on a simply connected domain and its applications

TL;DR

This paper generalizes the Bohr inequality for analytic functions in simply connected domains, explores its sharpness, and applies it to hypergeometric functions and quasiconformal harmonic maps.

Contribution

It introduces a generalized Bohr inequality in simply connected domains, determines the Bohr radius for hypergeometric functions, and extends results to quasiconformal harmonic maps.

Findings

Established a generalized Bohr inequality with sharpness in simply connected domains.

Determined the Bohr radius for hypergeometric functions on these domains.

Extended Bohr inequalities to K-quasiconformal harmonic maps.

Abstract

In this article, we first establish a generalized Bohr inequality and examine its sharpness for a class of analytic functions $f$ in a simply connected domain $\Omega_\gamma,$ where $0\leq \gamma<1$ with a sequence $\{\varphi_n(r) \}^{\infty}_{n=0}$ of non-negative continuous functions defined on $[0,1)$ such that the series $\sum_{n=0}^{\infty}\varphi_n(r)$ converges locally uniformly on $[0,1)$. Our results represent twofold generalizations corresponding to those obtained for the classes $\mathcal{B}(\mathbb{D})$ and $\mathcal{B}(\Omega_{\gamma})$, where \begin{align*} \Omega_{\gamma}:=\biggl\{z\in \mathbb{C}: \bigg|z+\dfrac{\gamma}{1-\gamma}\bigg|<\dfrac{1}{1-\gamma}\biggr\}. \end{align*} As a convolution counterpart, we determine the Bohr radius for hypergeometric function on $ \Omega_{\gamma} $. Lastly, we establish a generalized Bohr inequality and its sharpness for the class of $ K $-quasiconformal, sense-preserving harmonic maps of the form $f=h+\overline{g}$ in $\Omega_{\gamma}.$