Abstract
In the present paper, we investigate some Hermite-Hadamard inequalities related to generalized Riemann-Liouville fractional integral via exponentially convex functions. We also show the fundamental identity for having the first order derivative of a given exponentially convex function. Monotonicity and exponentially convexity of functions are used with some traditional and forthright inequalities. In the application part, we give examples and new inequalities for the special means.
1. Introduction
Recently, several researchers have attracted the fractional calculus, see References [1,2,3,4]. The effect and motivation of this fractional calculus in both theoretical and applied science and engineering rose substantially. Numerous studies related to the discrete versions of this fractional calculus have been established, which benefit from countless applications in the theory of time scales, physics, different fields of engineering, chemistry and so forth (e.g, see References [4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32] and the references therein).
A few decades ago, a lot of new operator definitions were given and the properties and structures of these operators have been examined. Some of these operators are very close to classical operators in terms of their characteristics and definitions. It is known that the , which was introduced in reference [33], extends several well-known fractional integral operators (see Remark 1 below). Both the generalized Riemann-Liouville fractional derivative and the integral operator are useful in the study of transform theory, quantum theory and fractional intgerodifferential equations.
Almost every mathematician knows the importance of convexity theory in every field of mathematics, for example in nonlinear programming and optimization theory. By using the concept of convexity, several integral inequalities have been introduced such as Jensen, and Slater inequalities, and so forth. But the well-known one is the celebrated inequality.
Let be an interval and be a convex function. Then the double inequality
holds for all with It is easy to see that if is concave on , one has the reverse of this inequality. This inequality provides bounds for the mean value of a convex function. Recently, mathematicians have focused on obtaining new variants of the inequality by giving generalizations, improvements, refinements and extensions, see References [34,35,36].
Exponentially convex functions have emerged as a significant new class of convex functions, which have important applications in technology, data science and statistics. The main motivation of this paper depends on new inequalities that have been proved via and applied for exponentially convex functions. This identity offers new upper bounds and estimations of type integral inequalities. Some particular cases have been discussed, which can be deduced from these consequences.
Recall the definition of an exponentially convex function, which is investigated by Dragomir and Gomm [34]:
Definition 1.
(See [34]) A positive real-valued function is said to be exponentially convex on K if the inequality
holds for and .
Exponentially convex functions are used to manipulate for statistical learning, sequential prediction and stochastic optimization, see References [37,38,39].
After the class of exponentially convex functions was introduced by Dragomir and Gomm [34], Alirezai and Mathar [37] have investigated the mathematical perspectives along with their fertile applications in statistics and information theory, see References [37,39]. Due to its significance, Pecaric and Jaksetic [40,41] used another kind of exponentially convex function introduced in Reference [42] and have provided some applications in Euler-Radau expansions and stolarsky means. Our intention is to use the exponentially convexity property of the functions as well as the absolute values of their derivatives in order to establish estimates for .
Definition 2.
([1,2,3]) Let be a finite or infinite real interval and Let be an increasing and positive monotone function on with a continuous derivative on Then the left and right-sided generalized Riemann-Liouville fractional integrals of a function on are defined by
and
respectively; with the classical gamma function.
Remark 1.
- 1.
- Setting , it turns into the both sided .
- 2.
- Setting , the Hadamard fractional integrals are obtained [1,3].
- 3.
- Setting it turns into the both sided Katugampola fractional integrals given in Reference [33].
- 4.
- Setting , the operators in reference [43] are obtained.
- 5.
- Setting it turns into the both sided generalized conformable fractional integrals defined by Khan et al. in reference [44].
The principal objective of this paper is to use a new convex class and a new integral operator to obtain new versions of -inequality that give bounds for the mean value of convexity. Also, we will establish some more general estimates and related modulus inequalities for via exponentially convex functions. In addition, the accuracy of the results was tested with applications of special means and with some examples.
2. Inequality for
Theorem 1.
Let be a positive function, for and Let is an increasing and positive monotone function on with continuous derivative on Let is an exponentially convex function and . Then
Proof.
Since is an exponentially convex function for we have
Let and we get
Multiplying by on both sides of inequality (6) and then integrating w.r.t over implies
Next, we again use the exponential convexity of that is,
Multiplying by on both sides of inequality (8), and then integrating w.r.t over implies
That is,
Hence the proof is completed. □
Our next result is the subsequent lemma, which is useful for our coming results.
Lemma 1.
Let be a differentiable mapping, for and . Let is an increasing and positive monotone function on with continuous derivative on and Then
Proof.
Consider
By making a change of variable in the above equation we have
Now
and
It follows that
This completes the proof. □
Theorem 2.
Let be a differentiable mapping, for and . Let be an increasing and positive monotone function on with continuous derivative on and If is exponentially convex and then
Proof.
First note that, for every , we have Let then we have Applying Lemma 1, Hlder’s inequality and exponentially convexity of we obtain
where
Now
Corollary 1.
Letting , then under the assumption of Theorem 2, we have
Proof.
Since is differentiable and strictly increasing function, we can write where as and and Then, the subsequent inequality holds true
By exponentially convexity of we have
By using (2) of Definition 2, we get
Now for and the subsequent inequality holds true
By exponentially convexity of we have
Adopting the same procedure as we did for (14) and (15), one can get from (17) and (18) the coming inequality
From inequalities (16) and (19), we get (13). Hence the proof is completed. □
Particular cases are stated as follows.
Corollary 2.
Choosing in (13), then we have a new inequality for ;
Corollary 3.
Choosing and in (13), adding the resulting inequalities, then the conditions of Theorem 1 are satisfied, we have
Corollary 4.
Theorem 3.
Let be the functions such that be differentiable function, Ψ is also differentiable and strictly increasing with Then for we have
where
respectively.
Proof.
From the convexity of we obtain
From (24), we have
Since is a differentiable and strictly increasing function, we have the subsequent inequality
where as and
Integrating over we have
and
Therefore (28) takes the form
Also from (24), one has
Following the same procedure as we did for (25), we also have
By convexity of we have
Now for and and the following inequality holds true
Particular cases are stated as follows.
Corollary 5.
To prove our next result we need the following Lemma.
Lemma 3.
Suppose that is an exponentially convex function which is symmetric about Then we have
Proof.
Write
Since is convex, therefore we have
Also, is symmetric about therefore we have and the inequality in (36) holds. □
Theorem 4.
Suppose that be an exponentially convex function such that is positive convex and symmetric about Ψ is a differentiable and strictly increasing function having Then we have
Proof.
Since is differentiable and strictly increasing function therefore where as and Hence, the following inequality holds true
From the exponential convexity of it can be obtained
By using (2) of Definition 2, we get
Now for and the following inequality holds true
Adopting the same procedure as we did for (38) and (39) one can get from (40) and (42) the subsequent inequality
Using Lemma 3 and multiplying (36) with and integrating over we get
By using (2) of Definition 2 we get
Similarly, using Lemma 3 and multiplying (36) with and integrating over we get
Corollary 6.
3. Examples
Example 5.
Let and . Then all the assumptions in Theorem 1 are satisfied.
Clearly,
and
Adding the above equations, we have the left-hand side term of (13)
On the other hand,
Example 6.
Clearly,
and
Adding the above equations, we get the left-hand term of (21)
Next,
Adding the above equations we get the right-hand side term of (21)
4. Applications
We consider the following special means for arbitrary real numbers
Now using the results in Section 1, we have some applications to the special means of real numbers.
Proposition 6.
For then
Proof.
Apply Theorem 2 with , and we obtain the desired result. □
Proposition 6.
For then
Proof.
Apply Theorem 2 with , and we obtain the desired result. □
Proposition 6.
Let then
Proof.
Apply Theorem 2 with , and we obtain the desired result. □
Proposition 6.
Let then
Proof.
Apply Theorem 2 with , and we obtain the general result. □
5. Conclusions
In this article, we have investigated a few fractional integral inequalities for via exponentially convexity. These inequalities have bounds of the sum of left-sided and right-sided fractional integrals and inequalities for the function, and their first derivative in absolute value is exponentially convex. Also, fractional inequalities of type for a symmetric and exponentially convex function are proved. These estimates, bounds and inequalities exist for all fractional operators are stated in Remark 1. The method followed to produce fractional inequalities is innovative and simple. It could be followed to broaden further consequences for other classes of functions related to exponentially convex functions, using convenient fractional integral operators.
Author Contributions
All authors contributed equally to the writing of this paper. All authors read and approved the final manuscript.
Funding
The second author would like to thank Prince Sultan University for funding this work through research, group Nonlinear Analysis Methods in Applied Mathematics (NAMAM) group number RG-DES-2017-01-17.
Acknowledgments
The authors are grateful to the reviewers for their valuable and constructive suggestions.
Conflicts of Interest
The authors declare no conflict of interest.
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