Results 21 to 30 of about 664 (120)

Remark on functions with all derivatives univalent

International Journal of Mathematics and Mathematical Sciences, 1980
An attractive conjecture is discounted for the class of normalized univalent functions whose derivatives are also univalent.
M. Lachance
doaj   +1 more source

Coefficient bounds for certain subclasses of starlike functions

Journal of Inequalities and Applications, 2019
The conjecture proposed by Raina and Sokòł [Hacet. J. Math. Stat. 44(6):1427–1433 (2015)] for a sharp upper bound on the fourth coefficient has been settled in this manuscript. An example is constructed to show that their conjectures for the bound on the
Nak Eun Cho, Virendra Kumar, Oh Sang Kwon, Young Jae Sim   +3 more
doaj   +1 more source

Hankel Inequalities for a Subclass of Bi-Univalent Functions based on Salagean type q-Difference Operator

Journal of Mathematical and Fundamental Sciences, 2020
In this investigation a new subclass of bi-univalent functions is established that is defined in the open unit disk Δ={𐌶 ∈ ℂ: |𐌶| < 1} and are endowed with the Sălăgean type q-difference operator.
Sibel Yalçın, Åžahsene Altınkaya, Gangadharan Murugusundaramoorthy, Kaliappan Vijaya   +3 more
doaj   +1 more source

Certain Coefficient Estimate Problems for Three-Leaf-Type Starlike Functions

Fractal and Fractional, 2021
In our present investigation, some coefficient functionals for a subclass relating to starlike functions connected with three-leaf mappings were considered.
Lei Shi, Muhammad Ghaffar Khan, Bakhtiar Ahmad, Wali Khan Mashwani, Praveen Agarwal, Shaher Momani   +5 more
doaj   +1 more source

Hölder Inequalities for a Generalized Subclass of Univalent Functions Involving Borel Distributions

Mathematics, 2022
In this article, by making use of the Borel distributions series, we introduce a new family of normalized holomorphic functions in the open unit disk and investigate necessary and sufficient conditions for functions f to be in this new class. Furthermore,
Gangadharan Murugusundaramoorthy, Luminiţa-Ioana Cotîrlǎ   +1 more
doaj   +1 more source

Coefficient Bounds for Certain Subclasses of q-Starlike Functions

Mathematics, 2019
By making use of q-calculus, we define and investigate several new subclasses of bi-univalent mappings related to the q-Noor integral operator. The coefficient bounds | u 2 | , | u 3 | and the Fekete−Szegő problem u ...
Lin-Lin Fan, Zhi-Gang Wang, Shahid Khan, Saqib Hussain, Muhammad Naeem, Tahir Mahmood   +5 more
doaj   +1 more source

Second Hankel Determinant for the Subclass of Bi-Univalent Functions Using q-Chebyshev Polynomial and Hohlov Operator

Fractal and Fractional, 2022
The q-derivative and Hohlov operators have seen much use in recent years. First, numerous well-known principles of the q-derivative operator are highlighted and explained in this research.
Isra Al-Shbeil, Timilehin Gideon Shaba, Adriana Cătaş   +2 more
doaj   +1 more source

Coefficient Bounds for Certain Classes of Meromorphic Functions

Journal of Inequalities and Applications, 2009
Sharp bounds for |a1−μa02| are derived for certain classes Σ∗(ϕ) and Σα∗(ϕ) of meromorphic functions f(z) defined on the punctured open unit disk for which −zf′(z)/f(z) and (−(1−2α)zf′(z)+Π...
K. Suchithra, H. Silverman, B. Adolf Stephen, A. Gangadharan   +3 more
doaj   +1 more source

Coefficient Bounds for Certain Subclasses of Bi-Univalent Function

Abstract and Applied Analysis, 2013
We introduce two new subclasses of the function class Σ of bi-univalent functions defined in the open unit disc. Furthermore, we find estimates on the coefficients |a2| and |a3| for functions in these new subclasses.
G. Murugusundaramoorthy, N. Magesh, V. Prameela   +2 more
doaj   +1 more source

HARMONIC MAPPINGS WITH THE FIXED ANALYTIC PART

Проблемы анализа, 2021
In this article, we consider a class of sense-preserving harmonic mappings whose analytic part is convex in one direction. We prove that functions in this class are close-to-convex for certain values of parameters.
Rajbala, Jugal K. Prajapat
doaj   +1 more source