Results 21 to 30 of about 22,022 (323)

Remark on functions with all derivatives univalent

open access: yesInternational 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

Coefficients and Fekete–Szegö Functional Estimations of Bi-Univalent Subclasses Based on Gegenbauer Polynomials

open access: yesMathematics, 2023
Subclasses of analytic and bi-univalent functions have been extensively improved and utilized for estimating the Taylor–Maclaurin coefficients and the Fekete–Szegö functional.
Abdulmtalb Hussen, Abdelbaset Zeyani
doaj   +1 more source

Univalent functions maximizing Re[f(ζ1)+f(ζ2)]

open access: yesInternational Journal of Mathematics and Mathematical Sciences, 1996
We study the problem maxh∈Sℜ[h(z1)+h(z2)] with z1,z2 in Δ. We show that no rotation of the Koebe function is a solution for this problem except possibly its real rotation, and only when z1=z¯2 or z1,z2 are both real, and are in a neighborhood of the x ...
Intisar Qumsiyeh Hibschweiler
doaj   +1 more source

On convolutions of slanted half-plane mappings

open access: yesJournal of Taibah University for Science, 2021
The convolution of convex harmonic univalent functions in the unit disk, unlike analytic functions, may not be convex or even univalent. The main purpose of this work is to develop previous work involving the convolution of convex harmonic functions ...
Elif Yaşar
doaj   +1 more source

Nonvanishing Meromorphic Univalent Functions [PDF]

open access: yesProceedings of the American Mathematical Society, 1988
This note studies the best constants s s such that the function k ( z ) = z + 2 + 1 / z k(z) = z + 2 + 1/z solves the linear coefficient problems max Re ⁡ { s
Abu-Muhanna, Yusuf, Schober, Glenn
openaire   +2 more sources

Subclasses of Bi-Univalent Functions Defined by Frasin Differential Operator

open access: yesMathematics, 2020
Let Ω denote the class of functions f ( z ) = z + a 2 z 2 + a 3 z 3 + ⋯ belonging to the normalized analytic function class A in the open unit disk U = z : z
Ibtisam Aldawish   +2 more
doaj   +1 more source

Boundary distortion estimates for holomorphic maps

open access: yes, 2013
We establish some estimates of the the angular derivatives from below for holomorphic self-maps of the unit disk at one and two fixed points of the unit circle provided there is no fixed point inside the unit disk. The results complement Cowen-Pommerenke
Frolova, A.   +3 more
core   +1 more source

Faber Polynomial Coefficient Estimates for Meromorphic Bi-Starlike Functions

open access: yesInternational Journal of Mathematics and Mathematical Sciences, 2013
We consider meromorphic starlike univalent functions that are also bi-starlike and find Faber polynomial coefficient estimates for these types of functions. A function is said to be bi-starlike if both the function and its inverse are starlike univalent.
Samaneh G. Hamidi   +2 more
doaj   +1 more source

Schwarzian Derivatives and Uniform Local Univalence

open access: yes, 2007
Quantitative estimates are obtained for the (finite) valence of functions analytic in the unit disk with Schwarzian derivative that is bounded or of slow growth. A harmonic mapping is shown to be uniformly locally univalent with respect to the hyperbolic
Chuaqui, Martin   +2 more
core   +2 more sources

Subordination by Univalent Functions [PDF]

open access: yesProceedings of the American Mathematical Society, 1981
Let K K be the class of functions f ( z ) = z + a 2 z 2 + ⋯ f(z) = z + {a_2}{z^2} + \cdots , which are regular and univalently convex in
Singh, Sunder, Singh, Ram
openaire   +1 more source

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