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Related papers: A generalized Bohr-Rogosinski phenomenon

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For a positive integer $m$ and a subgroup $\Lambda$ of the unit group $(\mathbb{Z}/m\mathbb{Z})^\times$, the corresponding generalized Kloosterman sum is the function $K(a,b,m,\Lambda) = \sum_{u \in \Lambda}e(\frac{au + bu^{-1}}{m})$.…

In this paper we investigate a certain category of cotangent sums and more specifically the sum $$\sum_{m=1}^{b-1}\cot\left(\frac{\pi m}{b}\right)\sin^{3}\left(2\pi m\frac{a}{b}\right)\:$$ and associate the distribution of its values to a…

Classical Analysis and ODEs · Mathematics 2017-09-21 Michael Th. Rassias

A generalization of Young's inequality for convolution with sharp constant is conjectured for scenarios where more than two functions are being convolved, and it is proven for certain parameter ranges. The conjecture would provide a unified…

Functional Analysis · Mathematics 2011-08-09 Sergey Bobkov , Mokshay Madiman , Liyao Wang

Many star bodies have convex subsets with approximately the same Gaussian measure (of the complement). Inspired by this phenomenon, and in connection with the randomized Dvoretzky theorem for Lorentz spaces, we derive bounds on the…

Functional Analysis · Mathematics 2022-06-22 Daniel J. Fresen

Ma-Minda class (of starlike functions) consists of all normalized analytic functions $f$ on the unit disk for which the image of $zf'(z)/f(z)$ is contained in the some starlike region in the right-half plane. We obtain the best possible…

Complex Variables · Mathematics 2019-10-14 Adiba Naz , Sushil Kumar , V. Ravichandran

Bohr's classical theorem and its generalizations are now active areas of research and have been the source of investigations in numerous function spaces. In this article, we study a generalized Bohr's inequality for the class of bounded…

Complex Variables · Mathematics 2022-05-04 Shankey Kumar

Recently the present authors established refined versions of Bohr's inequality in the case of bounded analytic functions. In this article, we state and prove a generalization of these results in a reformulated "distance form" version and…

Complex Variables · Mathematics 2021-03-25 Saminathan Ponnusamy , Ramakrishnan Vijayakumar , Karl-Joachim Wirths

In this paper, we investigate three specific subclasses of Ma-Minda type convex functions: namely, convex functions of order $\alpha$, Janowski convex functions, and Robertson functions of normalized analytic functions defined in the open…

Complex Variables · Mathematics 2026-03-19 Md Firoz Ali , Lokenath Thakur

We prove an extension of the Bourgain-Sarnak-Ziegler theorem and then apply it to bound certain polynomial exponential sums with modular coefficients.

Number Theory · Mathematics 2020-03-23 Mattia Cafferata , Alberto Perelli , Alessandro Zaccagnini

The purpose of this paper is twofold. First, we introduce a family of generalized Markov-Hurwitz equations, extending classical Markov-Hurwitz equations with additional degree n-1 interaction terms, Gyoda and Matsushita's generalized Markov…

Number Theory · Mathematics 2026-05-07 Zhichao Chen , Zelin Jia , Wenchao Wu

We introduce and study a class of starlike functions associated with the non-convex domain \[ \mathcal{S}^*_{nc} = \left\{ f \in \mathcal{A} : \frac{z f'(z)}{f(z)} \prec \frac{1+z}{\cos{z}} =: \varphi_{nc}(z), \;\; z \in \mathbb{D}…

Complex Variables · Mathematics 2024-12-09 S. Sivaprasad Kumar , Surya Giri

We propose a systematic method for analyzing Rohrlich-type divisor sums for arbitrary congruence subgroups $\Gamma_0(N)$. Our main theorem unifies various results from the literature, and its significance is illustrated through the…

Number Theory · Mathematics 2024-10-17 Daeyeol Jeon , Soon-Yi Kang , Chang Heon Kim , Toshiki Matsusaka

In this paper, we mainly study the order of $q$-starlikeness of the well-known basic hypergeometric function. In addition, we obtain the Bieberbach-type problem for a generalized class of starlike functions. We also discuss the…

Complex Variables · Mathematics 2018-09-11 Sarita Agrawal

We prove that the Bernardi Integral Operator maps certain classes of bounded starlike functions into the class of convex functions, improving the result of Oros and Oros. We also present a general unified method for investigating various…

Complex Variables · Mathematics 2025-03-21 Johnny E. Brown

We introduce a family of regularized functionals $g_n(x)$ that generalize the Euler--Mascheroni constant $\gamma$. They arise from a weighted regularization of Clausen-type trigonometric sums, and admit explicit integral representations,…

General Mathematics · Mathematics 2025-09-29 Ken Nagai

For a fixed $a \in \{1, 2, 3, \ldots\},$ the radius of starlikeness of positive order is obtained for each of the normalized analytic functions \begin{align*} \mathtt{f}_{a, \nu}(z)&:= \bigg(2^{a \nu-a+1} a^{-\frac{a(a\nu-a+1)}{2}} \Gamma(a…

Complex Variables · Mathematics 2017-07-04 Rosihan M. Ali , See Keong Lee , Saiful R. Mondal

Recent advances in image and signal processing have drawn on geometric function theory, particularly coefficient estimate problems. Motivated by their significance, we introduce a class of starlike functions related to a balloon-shaped…

Complex Variables · Mathematics 2026-02-19 S. Sivaprasad Kumar , A. Tripathi

We give some Korovkin-type theorems on convergence and estimates of rates of approximations of nets of functions, satisfying suitable axioms, whose particular cases are filter/ideal convergence, almost convergence and triangular…

Functional Analysis · Mathematics 2021-01-15 Antonio Boccuto , Xenofon Dimitriou

We study the functional equation \[ \sum_{i=1}^mf_i(b_ix+c_iy)= \sum_{k=1}^nu_k(y)v_k(x) \] with $x,y\in\mathbb{R}^d$ and $b_i,c_i\in {GL}(d,\mathbb{R})$, both in the classical context of continuous complex-valued functions and in the…

Classical Analysis and ODEs · Mathematics 2017-02-01 J. M. Almira , E. V. Shulman

In this paper, we study the Bohr inequality with lacunary series for vector-valued holomorphic functions defined in unit ball of finite dimensional Banach sequence space. Also, we study the Bohr-Rogosinski inequality for same class of…

Complex Variables · Mathematics 2025-09-05 Sabir Ahammed , Molla Basir Ahamed , Rajesh Hossain