Abstract
In recent years, special functions such as Bessel functions have been widely used in many areas of mathematics and physics. We are essentially motivated by the recent development; in our present investigation, we make use of certain conic domains and define a new class of analytic functions associated with the Dini functions. We derive inclusion relationships and certain integral preserving properties. By applying the Bernardi-Libera-Livingston integral operator, we obtain some remarkable applications of our main results. Finally, in the concluding section, we recall the attention of curious readers to studying the q-generalizations of the results presented in this paper. Furthermore, based on the suggested extension, the -extension will be a relatively minor and unimportant change, as the new parameter is redundant.
Keywords:
analytic function; univalent function; starlike and convex function; subordination; quasi-convex functions; Bessel functions; Dini functions MSC:
Primary 30C45; 30C50; 30C80; Secondary 11B65; 47B38
1. Introduction, Definitions and Motivation
The theory of special functions is an important component in most branches of mathematics. Special functions are applied in complicated mathematical calculations by engineers and scientists. The applications are covering a wide range of fields in physics, engineering and computer sciences. In the field of computer science, special functiona known as activation functions have a very important place. The widespread usage of these functions has attracted a large number of researchers to work in many areas. The study of the geometric properties of special functions such as Bessel functions, hypergeometric functions, Mittag-Leffler functions, Struve functions, Wright functions and other related functions is a continuing aspect of geometric function theory research. Some geometric properties of these functions can be found in [1,2,3].
Bessel functions are a set of solutions to a second-order differential equation that can appear in a variety of contexts. Bessel functions were initially employed by Bessel to explain three-body motion, with the Bessel functions appearing in the series expansion on planetary perturbation [4]. Euler, Lagrange and the Bernoullis also examined the Bessel functions. Now, consider the equation
which is a second-order linear homogeneous differential equation. The Equation (1) is well-known Bessel’s differential equation. Its solution is known as the Bessel function and is represented by , where is given as follows:
where represents the well-known Euler Gamma function; also, the well-known Pochhammar symbol is given by the relation
or
See [5] for a thorough examination of the first-order Bessel function.
The Dini function is a kind of special function and is the combination of the Bessel function of the first kind and is defined by
Moreover, the normalized Dini functions can be defined as (see [6])
where
Let the symbol mean the class of all analytic functions t in the open unit disk:
and having a Taylor-Maclaurin form as
Let , consisting of univalent functions in E and with the condition
Moreover, all normalized univalent functions in E are contained in the set . For two given functions , we say that is subordinate to written symbolically as if there exists a Schwarz function which is holomorphic in the open unit disk E with
so that
Moreover, if the function is univalent in E, then the following equivalence hold true:
For two given functions t and g from the class , the convolution (or Hadamard product) of these functions is given by
Let be the class of Carathéodory functions, consisting of all analytic functions p satisfying the conditions
and
Robertson [7] introduced and studied the classes of starlike and convex functions of order as follows
and
respectively. Note that if and only if (see also Srivastava and Owa [8]).
In 1964, Libera [9] introduced the class of close to convex functions of order and type which is defined by
Many researchers have recently examined different classes of analytic and univalent functions in various areas; see for more information [10,11,12,13,14,15,16,17,18]. By taking inspiration from the above-cited work, Shams et al. [19] introduced the domain for as follows:
Note that, for ,
for
Here, are the extremal functions for the conic domain, , and are given below:
where
and , is the first kind of Legendre’s complete elliptic integral.
We now give the following well-known subclasses of the analytic function.
Definition 1
(see [19]). A function is said to be in the class - if and only if
Definition 2
(see [19]). A function is said to be in the class - if and only if
We note that
Definition 3
(see [20]). A function is said to be in the class k- if and only if
Definition 4
(see [20]). A function is said to be in the class k- if and only if
The functions defined in (5) play the role of extremal functions for each of the above-defined function classes.
Remark 1.
First of all, it is easy to see that
where and are the functions classes introduced and studied by Robertson (see [7]). Secondly, we have
where k- and k- are the functions classes introduced and studied by Kanas and Wiśniowska (see [21]). Thirdly, we have
where and are the function classes introduced by Goodman [22] and also studied in [23,24].
Here, we remark that quantum calculus or simply q-calculus has many applications in different branches of mathematics and physics. Geometric function theory is one among them. In geometric function theory, the role of q-calculus is very important. Many new subclasses of analytic functions have been generalized and studied by giving it q-extension. Furthermore, by using the q-approach, deferent subclasses, which involve the conic domains, have been generalized. Some significant works on q-calculus in geometric function theory can be found in [25,26,27,28,29,30,31,32,33]. In particular, we call the attention of curious readers to the prospect of studying the q-generalizations of the results presented in this paper, influenced by a newly published survey-cum-expository review article by Srivastava [17]; see also [16].
The theory of the operator plays a vital role in the development of geometric function theory. Many new convolution operators have been defined and studied by well-known mathematicians. We are motivated by the above-mentioned works and the recent research; here, we now use the idea of convolution and introduce the operator as follows:
Here, in [34], the generalized Bernardi-Libera-Livingston integral operator is defined as follows:
In our present investigation, we make use of certain conic domains and define a new class of analytic functions associated with the Dini functions. We derive inclusion relationships and certain integral preserving properties. By applying the Bernardi-Libera-Livingston integral operator, we obtain some remarkable applications of our main results.
2. Preliminaries Results
In order to prove our main results, we need the following Lemmas.
Lemma 1
(In [35]). In For a convex univalent function h in E with the following conditions,
If the function p with is analytic in E, then we have
Lemma 2
(In [36]). Let h be convex in the open unit disk E, let and is analytic in E with
If is analytic in E with , then
3. Main Results
Theorem 1.
Let and h be convex univalent in E with
Proof.
Suppose that
where the function p belongs to the family of analytic functions in E, with the condition
Now, making use of (8), we have
Upon taking the logarithmic differentiation of the above equation with regard to , we find that
Now, by applying Lemma 1 in conjunction with the above equation, one can easily get the required result. □
Theorem 2.
Let . If - then -.
Proof.
Suppose that
where the function q is from the family of analytic functions in E with the condition From (8), we can write
Taking the logarithmic differentiation of the above equation with regard to , we find that
Since is convex univalent in E and
By making use of by Theorem 1, in conjunction with (6), we can get the desired result. □
Theorem 3.
Suppose that . If - then -.
Proof.
Making use of Definitions 1 and 2 in conjunction with Theorem 2, we have
Hence, Theorem 3 is completed. □
Theorem 4.
Let . If - then -.
Proof.
Since we see that
then, we have
Letting
It could be seen that both functions and are analytic in E with the following condition:
The following relation now holds true according to Theorem 2:
We observed that
Taking the differentiation of (10), we obtain
By using (8), we obtain
By taking and , we obtain
By making use of Lemma 2, we have
Then, by Definition 3, we get
Thus, we have now completed the proof of our Theorem 4. □
If we put in the above Theorem, we get the following Corollary.
Corollary 1.
Let . If - then -.
The next result (Theorem 5) can be proved similarly as we proved Theorem 4; therefore, we have chosen to omit the details involved in the proof of Theorem 5.
Theorem 5.
Let . If - then -.
In the next result, for the generalized Bernardi-Libera-Livingston integral operator , certain closure properties are investigated.
Theorem 6.
Let . If - then -.
Proof.
It could be seen that the following relation is due to applying the definition of and the linearity property of the operator
p is analytic in E with
On differentiating (14), we get
By using Lemma 1, we have
since
Hence, the proof of Theorem 6 is completed. □
If we put , in the above Theorem, we get the following Corollary.
Corollary 2.
Let . If - then -.
The following Theorem (Theorem 7) can be proved by using argumenty similar to those that are used in the proof of Theorem 6. Therefore, we choose to omit the details involved.
Theorem 7.
Let . If - then -.
Theorem 8.
Let . If - then -.
Proof.
By definition, we have
Now, from (13), we have
Since - by Theorem 6, we have -
Let
and
Now,
We now have that
Taking the differentiation of both sides of Equation (17), we have
By using the above equation along with (15), we have
By supposing along with the following
Finally, by making use of Lemma 2, we have our desired result. □
If we put , in the above Theorem, we have the following Corollary.
Corollary 3.
Let . If - then -.
The following Theorem (Theorem 9) can be proved by using arguments similar to those that are used in the proof of Theorem 6. Therefore, we choose to omit the details involved.
Theorem 9.
Let . If - then -.
4. Concluding Remarks and Observations
In our present investigation, we have studied some remarkable subclasses of analytic functions involving the Dini functions in conic domains. We have derived certain inclusion type results and the integral preserving properties for our defined function classes. We have also applied the well-known integral operator Bernardi-Libera-Livingston and have discussed some interesting applications of our main results.
Moreover, we recall the attention of curious readers to the prospect of studying the q-generalizations of the results reported in this paper, influenced by a newly published survey-cum-expository review article by Srivastava [17]; see also [3,16,37,38,39]. Furthermore, based on the suggested extension, the -extension will be a relatively minor and unimportant change, as the new parameter is redundant (see, for details, Srivastava [17], p. 340). Furthermore, in light of Srivastava’s recent result [5], the interested reader’s attention is brought to further investigation into the -extension of the Riemann-Liouville fractional integral.
Author Contributions
Conceptualization, S.K.; methodology, S.K., J.-S.R., S.A., N.K. (Nazar Khan) and N.K. (Nasir Khan); validation, B.K., J.-S.R., S.A., N.K. (Nazar Khan) and N.K. (Nasir Khan); formal analysis, B.K., S.K., J.-S.R., S.A. and N.K. (Nasir Khan); investigation, S.K. and N.K. (Nazar Khan); writing—original draft preparation, B.K., S.K., J.-S.R., S.A. and N.K. (Nazar Khan); writing—review and editing, B.K., J.-S.R., S.A., N.K. (Nazar Khan) and N.K. (Nasir Khan); funding acquisition, J.-S.R. All authors have read and agreed to the published version of the manuscript.
Funding
This research was supported by (1) Basic Science Research Program through the National Research Foundation of Korea funded by the Ministry of Education (2016R1D1A1B01008058). (2) Competency Development Program for Industry Specialists of the Korean Ministry of Trade, Industry and Energy (MOTIE), operated by the Korea Institute for Advancement of Technology (KIAT) (No. P0002397, HRD program for Industrial Convergence of Wearable Smart Devices).
Institutional Review Board Statement
Not applicable.
Informed Consent Statement
Not applicable.
Data Availability Statement
Not applicable.
Acknowledgments
The authors would like to thank the reviewers for their valuable suggestions and comments, which have improved the presentation of the paper substantially.
Conflicts of Interest
The authors declare that they have no competing interest.
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