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We study factorizations of operator valued functions of weighted Schur classes over multiply-connected domains. There is a correspondence between functions from weighted Schur classes and so-called ``conservative curved'' systems introduced…

Functional Analysis · Mathematics 2007-05-23 Alexey Tikhonov

Let $\mathcal{S}^*(\varphi)$ be the class of all analytic functions $f$ in the unit disk $\mathbb{D}=\{z\in\mathbb{C}:|z|<1\}$, normalized by $f(0)=f'(0)-1=0$ that satisfy the subordination relation $zf'(z)/f(z)\prec\varphi(z)$, where…

Complex Variables · Mathematics 2024-10-01 Md Firoz Ali , Md Nurezzaman , Sanjit Pal

Let D denote the Dirac operator in the Euclidean space R^m. In this paper, we present a refinement of the biharmonic functions and at the same time an extension of the monogenic functions by considering the equation DfD=0. The solutions of…

Complex Variables · Mathematics 2009-11-03 Helmuth R. Malonek , Dixan Peña Peña , Frank Sommen

The main object of the present paper is to, introduce the. class of meromorphic univalent functions Involving! hypergeomatrc function .We obtain~ some interesting geometric properties according to coefficient inequality , growth and…

Complex Variables · Mathematics 2020-05-15 Mazin Sh. Mahmoud , Abdul Rahman S. Juma , Raheam A. Mansor Al-Saphory

Let $f$ be a complex-valued harmonic mapping defined in the unit disk $\mathbb D$. We introduce the following notion: we say that $f$ is a Bloch-type function if its Jacobian satisfies $$ \sup_{z\in\mathbb D}(1-|z|^2)\sqrt{|J_f(z)|}<\infty.…

Complex Variables · Mathematics 2016-12-26 I. Efraimidis , J. Gaona , R. Hernández , O. Venegas

The radii of starlikeness and convexity associated with lemniscate of Bernoulli and the Janowski function, $(1+Az)/(1+Bz)$ for $-1\leq B<A\leq 1$, have been determined for normalizations of $q$-Bessel function, Bessel function of first kind…

Complex Variables · Mathematics 2019-06-14 Vibha Madaan , Ajay Kumar , V. Ravichandran

The purpose of the present paper is to find the necessary and sufficient conditions for the subclasses of analytic functions associated with Pascal distribution to be in subclasses of spiral-like univalent functions and inclusion relations…

Complex Variables · Mathematics 2020-07-22 G. Murugusundaramoorthy

By employing the $q$-difference operator, various classes of $q$-extensions of starlike functions have emerged from many different viewpoints and perspectives. Ruscheweyh's work unified these $q$-extensions with convolution operations.…

Complex Variables · Mathematics 2025-08-12 Ming Li , Ao-Li Zhu

In this paper we investigate an interesting subclass $\mathcal{BS}(\alpha)$ ($0\leq \alpha<1$) of starlike functions in the unit disk $\Delta$. The class $\mathcal{BS}(\alpha)$ was introduced by Kargar et al. [R. Kargar, A. Ebadian and J.…

Complex Variables · Mathematics 2018-02-13 R. Kargar , A. Ebadian , L. Trojnar-Spelina

In this paper our aim is to find the radii of $\gamma$-Spirallike of order $\alpha$ and convex $\gamma$-Spirallike of order $\alpha$ for three different kinds of normalizations of the function…

Complex Variables · Mathematics 2022-11-24 Sercan Kazımoğlu , Kamaljeet Gangania

Given a charge and current distribution with compact support, the associated potentials and fields are generally not integrable in the classical sense. However, it is convenient to be able to define their Fourier transform in order to…

Mathematical Physics · Physics 2024-03-15 Tristram de Piro

Let $p$ be an analytic function defined on the open unit disc $\mathbb{D}$ with $p(0)=1$ and $0< \alpha \leq 1$. The conditions on complex valued functions $C$, $D$ and $E$ are obtained for $p$ to be subordinate to $((1+z)/(1-z))^{\alpha}$…

Complex Variables · Mathematics 2020-07-07 Kanika Sharma , Nak Eun Cho , V. Ravichandran

In this paper, we obtain coefficient criteria for a normalized harmonic function defined in the unit disk to be close-to-convex and fully starlike, respectively. Using these coefficient conditions, we present different classes of harmonic…

Complex Variables · Mathematics 2012-06-05 S. V. Bharanedhar , S. Ponnusamy

For $0<\lambda \leq 1$, let ${\mathcal U}(\lambda)$ denote the family of functions $f(z)=z+\sum_{n=2}^{\infty}a_nz^n$ analytic in the unit disk $\ID$ satisfying the condition $\left |\left (\frac{z}{f(z)}\right )^{2}f'(z)-1\right |<\lambda…

Complex Variables · Mathematics 2017-09-20 Saminathan Ponnusamy , Karl-Joachim Wirths

We characterize the inclusions of weighted classes of entire functions in terms of the defining weights resp. weight systems. First we treat weights defined in terms of a so-called associated weight function where the weight(system) is…

Complex Variables · Mathematics 2024-01-24 Gerhard Schindl

Complex-valued harmonic functions that are univalent and sense-preserving in the open unit disk are widely studied. A new methodology is employed to construct subclasses of univalent harmonic mappings from a given subfamily of univalent…

Complex Variables · Mathematics 2012-09-04 Sumit Nagpal , V. Ravichandran

In this paper our aim is to find the radii of starlikeness and convexity of the normalized Wright functions for three different kind of normalization. The key tools in the proof of our main results are the Mittag-Leffler expansion for…

Classical Analysis and ODEs · Mathematics 2021-01-19 Árpád Baricz , Evrim Toklu , Ekrem Kadıoğlu

Let function $f$ be analytic in the unit disk ${\mathbb D}$ and be normalized so that $f(z)=z+a_2z^2+a_3z^3+\cdots$. In this paper we give sharp bounds of the modulus of its second, third and fourth coefficient, if $f$ satisfies \[…

Complex Variables · Mathematics 2018-10-15 Milutin Obradovic , Nikola Tuneski

In this paper we study the class $\mathcal{U}$ of functions that are analytic in the open unit disk ${\mathbb D}=\{z:|z|<1\}$, normalized such that $f(0)=f'(0)-1=0$ and satisfy \[\left|\left [\frac{z}{f(z)} \right]^{2}f'(z)-1…

Complex Variables · Mathematics 2018-12-24 Milutin Obradovic , Nikola Tuneski

We establish the membership criteria in terms of Hadamard product for a normalized analytic function to be in the class of infinitesimal generators. Furthermore, the embedding of various subclasses of normalized univalent functions in the…

Complex Variables · Mathematics 2022-10-25 Surya Giri , S. Sivaprasad Kumar