Abstract
In the present work, we introduce two new local fractional integral operators involving Mittag–Leffler kernel on Yang’s fractal sets. Then, we study the related generalized Hermite–Hadamard-type inequality using generalized -convexity and obtain two identities pertaining to these operators, and the respective first- and second-order derivatives are given. In terms of applications, we provide some new generalized trapezoid-type inequalities for generalized ()-convex functions. Finally, some special cases are deduced for different values of , E, and h.
Keywords:
fractal sets; generalized (E, h)-convexity; local fractional integral and derivative; generalized Mittag–Leffler function MSC:
52A41; 26A51; 26A33; 26D07
1. Introduction
Convexity is a significant concept in various fields of mathematics and related areas, such as economics, finance, and biology. It provides a powerful framework for exploring diverse topics in both pure and applied sciences. The idea of convexity is closely connected with the development of the theory of inequalities, which is an essential tool for analyzing particular aspects of solutions to differential equations and estimating the errors of quadrature formulas.
The most famous inequality related to convex functions is the so-called Hermite–Hadamard integral inequality, which can be stated as follows [1]:
where is a convex function on , with .
The class of convex functions has been extended to many more general classes, among which we can cite the class of h-convex functions introduced in [2] as follows:
Definition 1.
Let be a positive function and be an interval; then, is called h-convex if g is non-negative and the following inequality holds:
The class of h-convex functions includes many types of convexity, such as classical convexity (), s-convexity (), Godunova–Levin functions (), and P-functions ().
Modified h-convexity, generalized modified h-convexity, strong h-convexity, and generalized strongly modified h-convexity are studied in [3,4].
In [5], Sarikaya et al. provided the Hermite–Hadamard inequality related to h-convex functions.
Theorem 1.
([5]). Let be h-convex, and , with and . Then,
In [6], the author introduces the class of E-convex functions as follows:
Definition 2
([6]). A function is said to be E-convex, where , if
The Hermite–Hadamard inequality related to E-convex functions is presented in [7].
Theorem 2.
([7]). Let us assume that is a continuous increasing function and , with . A function is said to be E-convex on , if the following inequality holds:
Fractal sets and fractal theory have garnered considerable interest from scientists and engineers. According to Mandelbrot, a fractal set is one in which the Hausdorff dimension is greater than the topological dimension [8,9]. Several techniques of fractional calculus have been developed to study the properties of functions acting on fractal sets, such as those presented in [10,11,12,13,14,15,16,17,18,19]. The investigation and advancement of local fractional functions in fractal sets, including local fractional calculus and function monotonicity, are extensively studied by Yang in [20].
Conforming to Gao-Yang-Kang’s notion [20], the real line number in fractal set has the below properties.
If , and , where , then:
- .
- .
- .
- .
- .
- .
- .
The following definitions related to the local fractional calculus on are given in [20]:
Definition 3.
The local fractional derivative of of order δ at is given by
Definition 4.
Let g be a local fractional continuous on . The local fractional of function of order δ is defined by
where and , where , is a partition on and Γ is the well-known Gamma function .
The following defines the Mittag–Leffler function on fractal sets of order (see [20,21]):
Lemma 1.
The local fractional derivative and integral of the Mittag–Leffler function are given by
where τ is an arbitrary constant.
Two local fractional integral operators involving Mittag–Leffler kernel are described in [20,21].
Definition 5.
Let us assume that and . The local fractional left- and right-side integral operators of order are defined, respectively, by
On Yang’s fractal sets, the generalized h-convex function is defined in [22] as
Definition 6.
Let us consider that is a positive function; then, is called generalized h-convex if g is non-negative and the following inequality holds:
Some Hermite–Hadamard-type integral inequalities for local fractional integral operators involving Mittag–Leffler kernel using generalized h-convexity are studied in [23].
On Yang’s fractal sets, the generalized E-convex function is defined in [24] as
Definition 7.
A function is called a generalized E-convex function on a set if there exists a map such that U is an E-convex set and
where , and .
In this article, we focus on some local fractional integral inequalities involving Mittag–Leffler kernel using combined ()-convexity. First, we introduce two local fractional integral operators; then, we establish generalized Hermite–Hadamard-type inequalities related to these operators for the aforementioned class of functions. Finally, using two novel identities involving first-order and second-order local fractional derivatives, we establish some trapezium-type inequalities for the same class of functions.
2. Main Results
We begin this section with the following definitions:
Definition 8.
Let us consider that is a positive function and ; then, is called generalized -convex if g is non-negative and the following inequality holds:
This type of convexity, which combines generalized h-convexity and E-convexity, defines a larger and more comprehensive class of functions. Essentially, for , we obtain generalized E-convexity, and for , we obtain generalized h-convexity. Therefore, both of these types of convexity imply generalized -convexity, but the converse is false, as shown by the following example:
Example 1.
Let be a non negative function defined as follows:
Here, g is a generalized -convex function with respect to and , but not a generalized h-convex function.
Example 2.
Let us assume that
where , , and such that , . Consequently, g is a generalized ()-convex function but not a generalized h-convex function.
Definition 9.
Let us assume that and . The left- and right-side local fractional integral operators of order are defined, respectively, by
Remark 1.
- If , then Definition 8 returns to Definition 2 in [23].
- If , then
In what follows, we set .
Theorem 3.
Let us assume that is a positive function, with and . If g is a generalized ()-convex function on , then the following inequalities hold:
Proof.
Since g is a generalized ()-convex function on , then
Let us put and ; then,
By multiplying on both sides of inequality (16) and integrating the result into , we get
Let us put, and ; then,
Therefore, the first inequality of (15) holds.
Now, we prove the second inequality of (15). Since g is a generalized ()-convex function for , then
Adding the two sides of the above two inequalities gives
By multiplying on both sides of inequality (19) and integrating the result into , we obtain
From (17) and (18), the above inequality becomes
Therefore, the second inequality of (15) holds. This completes the proof. □
Remark 2.
- For , in the above Theorem, we obtain the following inequalities:
- Let ; then, we obtain the local fractional integral inequalities (3.3) in [23].
Corollary 1.
If in Theorem 3, then we obtain
Proof.
If , by using , we have
□
Lemma 2.
Let us assume that is a local fractional differentiable function on . If , then we obtain
Proof.
Theorem 4.
Let be a local fractional differentiable function on . If and is generalized ()-convex on , then we obtain
Proof.
Since h is a positive function and is generalized ()-convex on , then by using Lemma 2, we have
This completes the proof. □
Remark 3.
- For , we have
- If , then inequality (23) returns to inequality (3.17) in [23].
Corollary 2.
If in the last Theorem, we obtain
Proof.
If , by using ,
Hence,
The proof is completed. □
Lemma 3.
Let us assume that is a twice local fractional differentiable function on . If , we obtain
Proof.
Using local fractional integration by parts, then
Similarly, we have
Theorem 5.
Let be a twice local fractional differentiable function on . If and is generalized ()-convex on , then we obtain
Proof.
If we consider the function , then from [20], we have:
- is non-negative on .
- is increasing on .
- is decreasing on .
Then, function reaches its maximum at .
Consequently, we get
Now, since h is a positive function and is generalized ()-convex on , then by using Lemma 3, we have
This completes the proof. □
3. Application Examples
In this section, we provide examples to illustrate the application of results in the previous section.
Example 3.
Let ; we can obtain the following inequalities:
Proof.
By taking , since g is a generalized -convex function for and , and by applying Theorem 3, inequalities (27) are obtained. □
Example 4.
Let ; we can obtain the following inequalities:
Proof.
By taking , and , g is a classical h-convex function. So, according to the result in Remark 3, we obtain inequalities (28). □
4. Conclusions
In this paper, new generalized Hermite–Hadamard-type inequalities related to local fractional integral operators involving Mittag–Leffler kernel are established for the class of -convex functions on fractal sets. Then, some new trapezium-type inequalities are derived from two new identities using local fractional integrals involving first-order and second-order derivatives.
Author Contributions
Methodology, W.S., A.L. and O.A.; Validation, A.K.; Investigation, W.S. and O.A.; Writing—original draft, W.S.; Writing—review and editing, A.L. and A.K.; Supervision, A.K. All authors have read and agreed to the published version of the manuscript.
Funding
The research was not supported by any external funding sources.
Data Availability Statement
This study did not involve the collection or production of any underlying data.
Acknowledgments
The authors express their gratitude to the editor and the reviewers for their valuable and constructive feedback on this work.
Conflicts of Interest
The authors state that they have no conflict of interest to declare.
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