dorsal/arxiv
View SchemaSharp Bohr-Rogosinski radii for Schwarz functions and Euler operators in C^n
| Authors | Molla Basir Ahamed, Sujoy Majumder, Nabadwip Sarkar |
|---|---|
| Categories | |
| ArXiv ID | 2601.06630vv1 |
| URL | https://arxiv.org/abs/2601.06630 |
| License | http://creativecommons.org/licenses/by/4.0/ |
Abstract
This paper is devoted to the investigation of multidimensional analogues of refined Bohr-type inequalities for bounded holomorphic mappings on the unit polydisc $\mathbb{D}^n$. We establish a sharp extension of the classical Bohr inequality, proving that the Bohr radius remains $R_n = 1/(3n)$ for the family of holomorphic functions bounded by unity in the multivariate setting. Further, we provide a definitive resolution to the Bohr-Rogosinski phenomenon in several complex variables by determining sharp radii for functional power series involving the class of Schwarz functions $\omega_{n,m}\in\mathcal{B}_{n,m}$ and the local modulus $|f(z)|$. By employing the radial (Euler) derivative operator $Df(z) = \sum_{k=1}^{n} z_k \frac{\partial f(z)}{\partial z_k}$, we obtain refined growth estimates for derivatives that generalize well-known univariate results to $\mathbb{C}^n$. Finally, a multidimensional version of the area-based Bohr inequality is established. The optimality of the obtained constants is rigorously verified, demonstrating that all established radii are sharp.
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"abstract": "This paper is devoted to the investigation of multidimensional analogues of refined Bohr-type inequalities for bounded holomorphic mappings on the unit polydisc $\\mathbb{D}^n$. We establish a sharp extension of the classical Bohr inequality, proving that the Bohr radius remains $R_n = 1/(3n)$ for the family of holomorphic functions bounded by unity in the multivariate setting. Further, we provide a definitive resolution to the Bohr-Rogosinski phenomenon in several complex variables by determining sharp radii for functional power series involving the class of Schwarz functions $\\omega_{n,m}\\in\\mathcal{B}_{n,m}$ and the local modulus $|f(z)|$. By employing the radial (Euler) derivative operator $Df(z) = \\sum_{k=1}^{n} z_k \\frac{\\partial f(z)}{\\partial z_k}$, we obtain refined growth estimates for derivatives that generalize well-known univariate results to $\\mathbb{C}^n$. Finally, a multidimensional version of the area-based Bohr inequality is established. The optimality of the obtained constants is rigorously verified, demonstrating that all established radii are sharp.",
"arxiv_id": "2601.06630",
"authors": [
"Molla Basir Ahamed",
"Sujoy Majumder",
"Nabadwip Sarkar"
],
"categories": [
"math.CV"
],
"license": "http://creativecommons.org/licenses/by/4.0/",
"title": "Sharp Bohr-Rogosinski radii for Schwarz functions and Euler operators in C^n",
"url": "https://arxiv.org/abs/2601.06630",
"version": "v1"
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