1. Introduction
The discipline of quantum calculus, alternatively referred to as calculus, expands the conventional calculus framework to encompass the fundamental tenets of quantum mechanics. The field of mathematics commonly referred to as calculus is distinguished by the incorporation of a new parameter, denoted by q, that enables the generalization of traditional calculus concepts and methodologies. This area of study has garnered recognition for its widespread application in diverse mathematical domains, particularly in the realm of Geometric function theory.
The incorporation of the parameter q is a fundamental aspect of derivatives, integrals, and functions in the field of q-calculus. The q-derivative is a mathematical operator that utilizes q-analogs of traditional derivatives within a difference quotient. The q-integral is a mathematical construct that can be comprehended as the q-analog of the Riemann integral. q-calculus is a mathematical field that comprises a set of q-special functions that have significant applications in various areas of mathematics and physics. The set of functions under consideration encompasses q-binomial coefficients and q-factorials. Broadly speaking, q-calculus is a powerful tool for examining and solving problems pertaining to discrete and quantum systems.
The utilization of fractional calculus operators has been widely employed in the explanation and solution of issues in the field of applied sciences, as well as in Geometric Function, as documented in the source [
1]. The fractional
q-calculus is an extended form of the traditional fractional calculus and has been utilized in a variety of fields, including optimal control problems,
q-difference and
q-integral equations, and ordinary fractional calculus. To obtain additional insights on the topic at hand, it is advisable to refer to a published source [
2] and current literature, which may include references such as [
3,
4,
5].
2. Preliminaries
Consider the family
consisting of functions
of the form
where
ℑ belongs to the complex unit disk
, and
is analytic in ℧. Additionally,
must satisfy the normalization condition
. Furthermore, let
represent the subset of analytic functions in ℧ that fulfill the condition
and can be expressed in the form
where
(by Caratheodory’s Lemma refer to [
6]).
The implementation of differential subordination of analytical functions has the potential to offer considerable benefits to the domain of geometric function theory. Miller and Mocanu [
14] proposed the original differential subordination problem, which has subsequently been examined in greater detail in [
15]. The book authored by Miller and Mocanu [
16] presents a comprehensive overview of the advancements made in the field, accompanied by their respective dates of publication. For a real number
and
,
, the classes
,
and
where defined by
Janowski [
7] conducted an investigation and analysis of the class
, which is a subset of
. Additionally, other classes such as
and
were also studied and analyzed in previous works such as [
9,
10,
11], among others.
For any function
in the subfamily
, there exists an inverse function denoted as
and defined by
where
In a specified domain ℧, a function is considered to be bi-univalent if it satisfies the condition that both
and its inverse function
are univalent or injective within ℧.
The definition of the subclass
in the set
involves specifying the category of bi-univalent functions in ℧, as expressed by equation (
1). Examples of the class
functions include
The inverse functions that correspond to the aforementioned functions:
This article presents an overview of
q-calculus, initially introduced by Jackson and subsequently explored by numerous mathematicians [
17,
18,
19,
20,
21,
22,
23]. It focuses on introducing key concepts and definitions within the realm of
q-calculus. Additionally, it highlights the significance of the
q-difference operator, widely employed in scientific disciplines such as geometric function theory. Emphasizing the assumption that
q lies within the interval
, the study extensively relies on fundamental definitions and properties of
q-calculus, as extensively documented by Gasper and Rahman in their work [
12].
Definition 1.
Let . The bracket is formally defined as such
Definition 2.
The derivative, also known as the difference operator, of a function Φ
is defined by
and for
It is evident that as the limit is approached, the q-deformed generator tends towards the ordinary derivative of the function .
Definition 3.
[8] By letting . A function is in the class if it satisfies the following subordination:
where the values of and are given as
The function possesses a geometric meaning in the set if and only if the quotient spans across all values within a circular region centered at and with a radius of .
Motivated by Ismail et al. [
8], we introduce the class
by
Definition 4.
By letting . A function is in the class if it satisfies the following subordination:
where the values of and are given as
The primary objective of this study is to initiate an investigation into the characteristics of bi-univalent functions that are associated with q-univalent-preserving property. In order to attain this objective, the subsequent definitions are taken into account.
3. Definitions and Examples
In this section, we present some fresh subclasses that belong to the realm of bi-univalent functions. These subclasses are namely bi-starlike and bi-convex are defined using the subordination principal to the q-Janowski Function.
Definition 5.
By imposing and . A function f belonging to the family Σ,
as defined in equation (1), is considered to be a member of the bi-starlike class, denoted by if it satisfies certain subordination conditions. These conditions can be expressed as follows:
and
where the function is defined by the equation (3), and the values of and are given as
Definition 6.
By imposing and . A function f belonging to the family Σ,
as defined in equation (1), is considered to be a member of the bi-convex class, denoted by if it satisfies certain subordination conditions. These conditions can be expressed as follows:
and
where the function is defined by the equation (3), and the values of and are given as
Example 1.
Let . A function f belonging to the family Σ,
as defined in equation (1), is considered to be a member of the bi-starlike class if it satisfies the following subordination conditions:
and
where the function is defined by the equation (3).
Example 2.
Let . A function f belonging to the family Σ,
as defined in equation (1), is considered to be a member of the bi-convex class, denoted by if it satisfies the following subordination conditions:
and
where the function is defined by the equation (3).
Fekete and Szegö established a precise limit for the functional
in their 1933 publication [
56]. The limit was derived using real values of
and has been commonly known as the classical Fekete-Szeg"o outcome. Establishing precise boundaries for a given function within a compact family of functions
, and for any complex
, poses a formidable challenge.
4. The bounds of the coefficients within the bi-starlike class
Estimations for the initial coefficients of functions were discovered. Nevertheless, the issue of establishing precise coefficient limits for , is yet to be resolved, as indicated in several sources ([24–52]). Initially, the estimates for the coefficients of the class , as defined in Definition 5, are provided.
Theorem 1.
If Φ
is an element of Σ
defined by (1), it can be said that Φ
is a member of the class , as per the following statement:
Proof. If
belongs to the class
, according to Definition 5, under the given conditions, there exist analytic functions
and
such that
, and
and
hold for all
ℑ and
in the unit disk ℧. In light of these conditions, the function
can be expressed as follows:
and
For
, we have
Next we calculate the values of
and
. Taking
then, we get
Comparing Equations (
16) and (
17), we have
By utilizing equations (
14) and (
15) along (
18), we can derive the following expression.
and
There is a commonly accepted understanding that if.
and
then for all
, we have
In view of (
1), (
3), from (
19) and (
20), we obtain
and
By comparing the pertinent coefficients in (
19) and (
20), we arrive at the following.
and
It follows from (
22) and (24) that
and
Adding (24) and (
25), we get
Substituting the value of
from (
27), we obtain
Applying for the coefficients
and
along the equation (
21), we obtain
The subtraction of equation (
25) from equation (24) yields the following result:
Then, in view of (
26) and (
27), Eq. (
30) becomes
Thus applying (
21), we conclude that
This completes the proof of Theorem. □
The Fekete-Szeg"o inequality for functions belonging to the class
is examined in view of Zaprawa’s [
57] finding.
Theorem 2.
Given that Φ
is an element of Σ
defined by (1) and belongs to the class , and μ is a real number, we can state the following
Proof. If
is given by (
1), from (
29) and (
30), we have
where
Then, we conclude that
Which completes the proof of Theorem 2. □
5. The bounds of the coefficients within the bi-convex class
In next theorem, the estimates for the coefficients of the class , as defined in Definition 6, are provided.
Theorem 3.
If Φ
is an element of Σ
defined by (1), it can be said that Φ
is a member of the class , as per the following statement:
and
Proof. If
belongs to the class
, according to Definition 6, under the given conditions, the function
can be expressed as follows:
and
By utilizing equations (
31) and (
32) along (
16-
18), we can derive the following expression.
and
In view of (
1), (
3), from (
33) and (
34), we obtain
and
By comparing the pertinent coefficients in (
19) and (
20), we arrive at the following.
and
It follows from (
35) and (37) that
and
Adding (37) and (
38), we get
Substituting the value of
from (
40), we obtain
Applying for the coefficients
and
along the equation (
21), we obtain
The subtraction of equation (
38) from equation (37) yields the following result:
Then, in view of (
39) and (
40), Eq. (
43) becomes
Thus applying (
21), we conclude that
This completes the proof of Theorem. □
In the last theorem, we examine the Fekete-Szeg"o inequality for functions belonging to the class .
Theorem 4.
Given that Φ
is an element of Σ
defined by (1) and belongs to the class , and ϵ is a real number, we can state the following
where
Proof. If
is given by (
1), from (
42) and (
43),
we have
where
Then, we conclude that
Which completes the proof of Theorem 4. □
6. Corollaries
The theorems presented in this study, namely Theorems 1 and 2, lead to the derivation of several corollaries that closely resemble the illustrative examples provided in Examples 1 and 2. These corollaries serve to further demonstrate and validate the results obtained from the theorems. By applying the principles and findings established in Theorems 1 and 2, these corollaries offer additional concrete instances that align with the examples previously discussed, providing further insight and supporting the overall conclusions of this study.
Corollary 1.
If Φ
is an element of Σ
defined by (1), it can be said that Φ
is a member of the class , as per the following statement:
and
Corollary 2.
If Φ
is an element of Σ
defined by (1), it can be said that Φ
is a member of the class , as per the following statement:
and
Conclusion: The present investigation pertains to the examination of the coefficient problems that arise in the context of the newly introduced subclasses of bi-univalent functions using q-Janowski Function, as defined in Definitions 5 and 6, over the disk ℧. The subclasses under consideration are denoted by , , , and . The determination of the Taylor-Maclaurin coefficients and , as well as the evaluation of the Fekete-Szegö functional problem, has been performed on functions belonging to the aforementioned subclasses of . Through the specialization of parameters in our primary discoveries, we have discerned a number of supplementary novel outcomes. The utilization of fractional q-derivative operators is anticipated to have extensive implications in diverse scientific domains, encompassing mathematics and technology.
Author Contributions
Conceptualization, A.A. (Abdullah Alsoboh) and F.M.S.; methodology, A.A. (Ala Amourah) and A.A. (Abdullah Alsoboh); validation, F.M.S. and D.B.; formal analysis, A. Alsoboh; investigation, A. Amourah, A.A. (Abdullah Alsoboh) and D.B.; writing—original draft preparation, A.A. (Ala Amourah); writing—review and editing, A.A. (Abdullah Alsoboh) and A.A. (Ala Amourah); supervision, A.A. (Abdullah Alsoboh) All authors have read and agreed to the published version of the manuscript.
Institutional Review Board Statement
Not applicable.
Informed Consent Statement
Not applicable.
Data Availability Statement
No data were used to support this study.
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