Abstract
In this paper, the Jackson q-derivative is used to investigate two classes of analytic functions in the open unit disc. The coefficient conditions and inclusion properties of the functions in these classes are established by convolution methods.
MSC:
30C45; 30C50; 30C55; 30C80
1. Introduction
Let be the class of functions that are analytic and of the form:
The Hadamard product (or convolution) of two functions , denoted by is defined by
where f is given by (1) and In 1978, Silverman et al. [1] obtained characterizations of convex, starlike and spiral-like functions in terms of convolutions. For each of these classes , they determined a function g that depends on , such that . both fundamental and adequate for f to be in . As a result of the work by Silverman et al. [1], many important properties of certain subclasses of analytic functions were studied by various authors (for related works, one may refer to [2,3,4,5,6,7,8]). For q∈ the Jackson q-derivative of a function f is given by (see [9,10])
Moreover, we have the following q-derivative rules
and
We recall a known differential operator which was introduced by Govindaraj and Sivasubramanian (see [11]), and is also known as the Salagean q-differential operator, defined recursively on as follows: For and q∈
Then, we find that
where
Definition 1.
A function is said to be in the class if and only if
where q∈ is the Jackson q-derivative and ≺ denotes the usual subordination (see [12,13,14] ).
Definition 2.
A function is said to be in the class if and only if
where ∈ and is the Jackson q-derivative.
With the help of the Salagean q-differential operator given by (5), we have the following definition.
Definition 3.
A function is said to be in the class if and only if
where q∈ and
In this paper, we use a technique similar to that given by Silverman et al. [1] in order to obtain certain convolution properties of the two classes and . Furthermore, the coefficient conditions and inclusion properties of the functions in these classes are established.
2. Convolution Conditions
Theorem 1.
Proof.
Let function f be in the class if and only if
which is equivalent to
which simplifies to
Since
and
This implies that
Then, (12) can be rewritten as the following
Hence, the first part of Theorem 1 was proven.
Conversely, since assumption (8) holds for it follows that
hence the function is analytic in (i.e., it is regular in , with ).
We obtain from the first part that
If we denote
relation (14) shows that . Thus, the simply connected domain is included in a connected component of From here, using the fact that together with the univalent of the function , it follows that ; that is . Thus, the second part of Theorem 1 was proven. □
Taking in Theorem 1, we get the following corollary.
Corollary 1.
Letting in Theorem 1, we acquire the following corollary.
Corollary 2.
Theorem 2.
Proof.
Note that
From Theorem 1, we have if and only if
where and Now we can easily deduce that
This finishes the proof of Theorem 2. □
Theorem 3.
If satisfies the inequality
then
Proof.
Since
then,
Thus, from Theorem 2, we have , which ends the proof. □
Theorem 4.
Proof.
Since,
By utilizing the property, if and then (21) can be written as
which means that This finishes the proof of Theorem 4. □
Theorem 5.
Proof.
Note that
This finishes the proof of Theorem 5. □
Taking in Theorem 5, we get the following corollary.
Corollary 3.
Letting in Corollary( 3), we acquire the following corollary.
Corollary 4.
3. Conclusions
In this paper, we introduced and studied two new subclasses of analytic functions in the open unit disc using the Jackson q-derivative. A similar technique to that given by Silverman et al. [1] was used to obtain certain convolution properties for these two classes. In addition, the coefficient conditions and inclusion properties of these classes are established. Several special cases have been examined as applications of our main results.
Author Contributions
Conceptualization, A.M.Y.L.; Funding acquisition, B.M.A.; Investigation, B.M.A.; Project administration, A.O.B.; Supervision, A.M.Y.L. and A.O.B.; Writing (original draft), B.M.A.; Writing (review and editing), A.M.Y.L. and A.O.B. All authors have read and agreed to the published version of the manuscript.
Funding
This research was funded by the Deanship of Scientific Research (DSR) at King Abdulaziz University, Jeddah, Saudi Arabia(FP-212-43).
Institutional Review Board Statement
Not applicable.
Informed Consent Statement
Not applicable.
Acknowledgments
The authors would like to express their thanks to the referees for their helpful comments and suggestions that improved the presentation of the paper.
Conflicts of Interest
The authors declare no conflict of interest.
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