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For an analytic and univalent function $f$ in the unit disk $\mathbb{D}:=\{z\in\mathbb{C}:|z|<1\}$ with the normalization $f(0)=0=f'(0)-1$, the logarithmic coefficients $\gamma_n$ are defined by $\log \frac{f(z)}{z}= 2\sum_{n=1}^{\infty}…

Complex Variables · Mathematics 2016-10-03 Md Firoz Ali , D. K. Thomas , A. Vasudevarao

In this paper, estimates for second and third MacLaurin coefficients of certain subclasses of bi-univalent functions in the open unit disk defined by convolution are determined, and certain special cases are also indicated. The main result…

Complex Variables · Mathematics 2015-03-17 Pranay Goswami , Badr Alkahtani , Teodor Bulboaca

Let ${\mathcal A}$ be the class of functions analytic in the unit disk ${\mathbb D} := \{ z\in {\mathbb C}:\, |z| < 1 \}$ and normalized such that $f(z)=z+a_2z^2+a_3z^3+\cdots$. In this paper we study the class $\mathcal{U}(\lambda)$,…

Complex Variables · Mathematics 2021-04-23 N. M. Alarifi , M. Obradovic , N. Tuneski

Generalizing the Zalcman conjecture given by $\vert a_n^2 - a_{2n-1}\vert \leq (n-1)^2$, Ma proposed and proved that the inequality $$\vert a_n a_m-a_{n+m-1}\vert \leq (n-1)(m-1), \quad m,n \in \mathbb{N},$$ holds for functions…

Complex Variables · Mathematics 2026-02-02 Surya Giri

A motivation comes from {\em M. Ismail and et al.: A generalization of starlike functions, Complex Variables Theory Appl., 14 (1990), 77--84} to study a generalization of close-to-convex functions by means of a $q$-analog of a difference…

Complex Variables · Mathematics 2015-04-02 S. K. Sahoo , N. L. Sharma

The celebrated union-closed conjecture is concerned with the cardinalities of various subsets of the Boolean $d$-cube. The cardinality of such a set is equivalent, up to a constant, to its measure under the uniform distribution, so we can…

Combinatorics · Mathematics 2025-11-05 Gabriel Gendler

Inspired by the recent works of Srivastava et al. (2010), Frasin and Aouf (2011), and Caglar et al. (2013), we introduce and investigate in the present paper two new general subclasses of the class consisting of normalized analytic and…

Complex Variables · Mathematics 2021-02-18 Feras Yousef , Somaia Alroud , Mohamed Illafe

We prove the Jacobian Conjecture for the space of all the inner functions in the unit disc.

Complex Variables · Mathematics 2014-09-05 Ronen Peretz

We give some coefficient bounds and distortion theorems for a subclass of univalent functions in the unit disk, and defined using the S\^{a}l\^{a}gean differential operator. The results generalize and unify some well known results for…

Complex Variables · Mathematics 2012-10-08 Ben Ntatin

A. Grinshpan posed a deep conjecture on the norm of the Grunsky operator generated by univalent functions in the disk. It gives a quantitative answer in terms of the Grunsky coefficients, to which extent a univalent function determines the…

Complex Variables · Mathematics 2022-05-18 Samuel L. Krushkal

We introduce some generalized topological concepts to deal with union-closed families, and show that one can reduce the proof of Frankl's conjecture to some families of so-called supratopological spaces. We prove some results on the…

Combinatorics · Mathematics 2025-09-18 André Carvalho , António Machiavelo

We show that the subgroup lattice of any finite group satisfies Frankl's Union-Closed Conjecture. We show the same for all lattices with a modular coatom, a family which includes all supersolvable and dually semimodular lattices. A common…

Combinatorics · Mathematics 2020-07-08 Alireza Abdollahi , Russ Woodroofe , Gjergji Zaimi

Let ${\cal F}$ be a family of meromorphic functions on a domain $D$. We present a quite general sufficient condition for ${\cal F}$ to be a normal family. This criterion contains many known results as special cases. The overall idea is that…

Complex Variables · Mathematics 2017-10-17 Andreas Schweizer

In this paper we discuss a conjecture on intermediate subfactors which is a generalization of Wall's conjecture from the theory of finite groups. We explore special cases of this conjecture and present supporting evidence. In particular we…

Operator Algebras · Mathematics 2010-07-01 Robert Guralnick , Feng Xu

In this article, we define a very important sequence of functions, all the functions of this sequence present behaviors very close to that of the Collatz function. The study of such functions allows us to obtain very interesting results…

General Mathematics · Mathematics 2021-07-13 Raouf Rajab

In the present paper, we obtain a more general conditions for univalence of analytic functions in the open unit disk U. Also, we obtain a refinement to a quasiconformal extension criterion of the main result.

Complex Variables · Mathematics 2013-02-19 Murat Çağlar , Halit Orhan

In this paper, we first prove the coefficient conjecture of Clunie and Sheil-Small for a class of univalent harmonic functions which includes functions convex in some direction. Next, we prove growth and covering theorems and some related…

Complex Variables · Mathematics 2014-03-25 S. Ponnusamy , A. Sairam Kaliraj

In this paper our aim is to extend and improve the sufficient conditions for integral operators involving the normalized forms of the generalized Bessel functions of the first kind to be univalent in the open unit disk as investigated…

Complex Variables · Mathematics 2014-08-13 H. A. Al-Kharsani , Abeer M. Al-Zahrani , S. S. Al-Hajri

We prove a one-parameter family of sharp integral inequalities for functions on the $n$-dimensional unit ball. The inequalities are conformally invariant, and the sharp constants are attained for functions that are equivalent to a constant…

Functional Analysis · Mathematics 2012-01-31 Shibing Chen

A normalized analytic function f is shown to be univalent in the open unit disk D if its second coefficient is sufficiently small and relates to its Schwarzian derivative through a certain inequality. New criteria for analytic functions to…

Complex Variables · Mathematics 2011-08-30 Rosihan M. Ali , Mahnaz M. Nargesi , V. Ravichandran , A. Swaminathan