A Special Class of Harmonic Univalent Functions

In this article, a new class of harmonic univalent functions, defined by the differential operator, is introduced. Some geometric properties, like, coefficient estimates, extreme points, convex combination and convolution (Hadamard product) are obtained.

In this paper, we introduce a new class of harmonic univalent functions with respect to k-symmetric points by using a newly-defined q-analog of the derivative operator for complex harmonic functions. For this harmonic univalent function class, we derive a sufficient condition, a representation theorem, and a distortion theorem. We also apply a generalized q-Bernardi–Libera–Livingston integral operator to examine the closure properties and coefficient bounds. Furthermore, we highlight some known consequences of our main results. In the concluding part of the article, we have finally reiterated the well-demonstrated fact that the results presented in this article can easily be rewritten as the so-called (p,q)-variations by making some straightforward simplifications, and it will be an inconsequential exercise, simply because the additional parameter p is obviously unnecessary.

Let SH be the class of functions f = h+g that are harmonic univalent and sense-preserving in the open unit disk U = { z : |z| < 1} for which f (0) = f'(0)-1=0. In this paper, we introduce and study a subclass H( α, β) of the class SH and the subclass NH( α, β) with negative coefficients. We obtain basic results involving sufficient coefficient conditions for a function in the subclass H( α, β) and we show that these conditions are also necessary for negative coefficients, distortion bounds, extreme points, convolution and convex combinations. In this paper an attempt has also been made to discuss some results that uncover some of the connections of hypergeometric functions with a subclass of harmonic univalent functions.

In this paper, a class of complex-valued harmonic univalent functions f (z) in the open disk U is defined by fractional calculus operator. We obtained coefficient bounds, distortion inequalities, convex combination, extreme points and convolution conditions for this class.

By applying Ruscheweyh derivative on the class ASH(λ, α, k, γ )o f harmonic univalent functions in the unit disk U , we obtain several interesting properties such as sharp coefficient relations, distortion bounds, extreme points, Hadamard product, and other results.

We introduce new classes of meromorphic harmonic univalent functions. Using the duality principle, we obtain the duals of such classes of functions leading to coefficient bounds, extreme points and some applications for these functions.

In this paper, a new subclass of complex-valued harmonic univalent functions f(z)=h(z)+g(z)¯¯¯¯¯¯¯¯¯ in the open disk U={z:z∈C and |z|<1} defined by using a linear operator. We investigate coefficient condition, extreme points, distortion and convex combination for this subclass.

In this paper, using Hadmard product, we introduce certain new classes of analytic functions in the open unit disk. Such results as inclusion and subordination relationships, characterization and coecient estimates, growth and distortion theorems, extreme points, closure theorems and radius of starlikeness and convexity belonging to the class TS(f;g;;;;A;B ) are obtained. Further subordination results for the class S(f;g;;;;A;B ) are derived:

We shall start with the analytic foundations and, building upon this, treat existence, regularity, and uniqueness of harmonic maps; in the course of that, already some geometric applications will occur. The A role of harmonic maps in Riemannian and Kahlerian geometry will then be discussed somewhat more systematically in the subsequent paragraphs. The last paragraph finally is devoted to a novel development of Teichmuller theory via harmonic maps.

The purpose of the present paper is to introduce a new subclass of harmonic univalent functions associated with a $q$-Ruscheweyh derivative operator. A necessary and sufficient convolution condition for the functions to be in this class is obtained. Using this necessary and sufficient coefficient condition, results based on the extreme points, convexity and compactness for this class are also obtained.

In this paper, we obtain a new characterization for univalent harmonic mappings and obtain a structural formula for the associated function which defines the analytic -like functions in the unit disk. The new criterion stated in this article for the injectivity of harmonic mappings implies the well-known results of Kas’yanyuk [10] and Brickman [3] for analytic functions, but with a simpler proof than theirs. A number of consequences of the characterization, and examples are also presented. Further investigation provides a new method to construct univalent harmonic mappings with the help of an improved distortion theorem.

Making use of a convolution structure, we introduce a new class of analytic functions PTg(λ,α,β,γ) defined in the open unit disc and investigate its various characteristics. Further we obtained distortion bounds , extreme points and radii of close-to-convexity, starlikeness and convexity for functions belonging to the class PTg(λ,α,β,γ).

In this article we consider classes of harmonic and subharmonic functions introduced with using integral operators Riman-Liouville by Professor M. Djrbashyan when α > 0. These classes are significant generalizations of already well known classes of harmonic and subharmonic functions match up with them only in a particular case. In our article we consider angular and chordal limits of harmonic and subharmonic functions got by using Riman-Liouville integral operators. A set of the points at which, probably, these limits don’t exist are characterized by using a linear measure of zero.

We consider the class of all sense-preserving complex-valued harmonic mappings f = h + g ¯ f=h+\overline {g} defined on the unit disk D \mathbb {D} with the normalization h ( 0 ) = h ′ ( 0 ) − 1 = 0 h(0)=h’(0)-1=0 and g ( 0 ) = g ′ ( 0 ) = 0 g(0)=g’(0)=0 with the second complex dilatation ω : D → D \omega :\,\mathbb {D}\rightarrow \mathbb {D} , g ′ ( z ) = ω ( z ) h ′ ( z ) g’(z)=\omega (z)h’(z) . In this paper, the authors determine sufficient conditions on h h and ω \omega that would imply the univalence of harmonic mappings f = h + g ¯ f=h+\overline {g} on D \mathbb {D} .

In this paper, using Differential operator a certain subclass of harmonic univalent functions in the unit disc U = {z ∈ C : |z| < 1} is investigated. Some properties such as coefficient bounds, convex combination, extreme points and convolution conditions of this class are obtained. The newly introduced subclass of harmonic univalent functions is more general than the subclasses earlier found in the literature.