Abstract
In this paper, we propose some generalized integral inequalities of the Raina type depicting the Mittag–Leffler function. We introduce and explore the idea of generalized s-type convex function of Raina type. Based on this, we discuss its algebraic properties and establish the novel version of Hermite–Hadamard inequality. Furthermore, to improve our results, we explore two new equalities, and employing these we present some refinements of the Hermite–Hadamard-type inequality. A few remarkable cases are discussed, which can be seen as valuable applications. Applications of some of our presented results to special means are given as well. An endeavor is made to introduce an almost thorough rundown of references concerning the Mittag–Leffler functions and the Raina functions to make the readers acquainted with the current pattern of emerging research in various fields including Mittag–Leffler and Raina type functions. Results established in this paper can be viewed as a significant improvement of previously known results.
Keywords:
convex function; Hölder’s inequality; Hölder-Íscan inequality; improved power-mean integral inequality; s-type convexity MSC:
26A51; 26A33; 26D07; 26D10; 26D15
1. Introduction
The Hermite–Hadamard inequality, which is the primary consequence of convex functions having a beautiful geometrical understanding and broad use, has stood out with incredible interest in fundamental mathematics. Numerous mathematicians have given their endeavors to normalization, refining, impersonation, and extension of the Hermite–Hadamard inequality using different types of novel convexities.
The theory of convexity is an incredible and viable methodology for contemplating the huge greatness of issues that emerges in different fields of pure and applied sciences. Many new structures have been presented and researched concerning convex sets and convex mappings. A few scientists have inferred new variations related with convex mappings, see references [1,2,3,4,5]. Integral inequalities on the Raina function have additionally been a subject of discussion for a significant length of time. Because of their possibilities to be extended, a few variations have been set up by many mathematicians, see references [6,7].
The theory of convex mappings has a wide scope of possible applications in many interesting and captivating fields of exploration. Moreover, this theory likewise assumes an eminent part in different areas, such as information theory, coding theory, engineering, optimization, and inequality theory. Guessab et al. [8,9,10] worked on the error estimations and multivariate approximation theory. Presently, this hypothesis has an amazing commitment to the expansions and enhancements of various areas of numerical and applied sciences. Many mathematicians inspected, celebrated, and played out their work on the thoughts of convexity and expanded its various forms in helpful manners utilizing productive techniques and imaginative thought. For some of the recent considerations, we refer to the references [11,12,13,14].
2. Preliminaries
In this section we recall some known concepts.
Definition 1
([5]). Let be a real valued function. A function is said to be convex, if
holds for all and
The most important inequality concerning convex functions is the Hermite–Hadamard inequality given as:
Theorem 1.
If is a convex function, then
The double inequality (2) holds in reverse direction if is a concave function on and the constant is sharp and cannot be replaced by a similar constant. Since then, various papers with new proof, various speculations, and advancements have been proposed in the literature. This type of inequality has remained an area of great interest due to its widespread view and applications in the field of mathematical analysis.
In 2005, Raina [15] introduced a class of functions defined formally by
where and . The above class of function is the generalization of classical Mittag–Leffler function and the Kummer function.
If and for where and are parameters which can take arbitrary real or complex values (provided that and the symbol denotes the quantity
and restricts its domain to (with ), then we have the classical hypergeometric function, that is
Moreover, if with , then
The above exact function, which intermittently appears in the investigation of fractional integrals and derivatives is called a classical Mittag–Leffler function, and was first considered by Magnus Gustaf (Gösta) Mittag–Leffler (1846–1927) in 1903 and Anders Wiman (1865–1959) in 1905.
From that point forward, the Mittag–Leffler function has been broadened and explored in numerous elective ways and settings. Mittag–Leffler type functions with all of their applications have reached out in different investigations like those in science, physics, engineering, statistics, and mathematics.
The Mittag–Leffler function emerges normally in the arrangement of fractional order integral equations and particularly in the investigations of the fractional speculation of the kinetic equation, random walks, Lévy flights, superdiffusive transport, and in the investigations of complex frameworks. In numerous new research articles, the interest in the group of Mittag–Leffler type functions has become impressive due primarily to their potential for applications in reaction–diffusion and other applied issues and their different speculations show up in the arrangements of fractional order differential and integral equations, see the references [16,17,18].
Cortez established the new class of set and function involving Raina’s function in [6,7], which is said to be generalized convex set and convex function.
Definition 2
([7]). Let and . A set is said to be generalized convex, if
for all and
Definition 3
([7]). Let σ denote a bounded sequence then and . If satisfies the following inequality
for all where and then is called generalized convex function.
Remark 1.
We have and so we obtain Definition 1.
Condition 1.
Let be an open generalized convex subset with respect to . For any and
Note that, for every and for all from Condition 1, we have
Definition 4
([19]). A nonnegative function is called s-type convex function if for every and if
Definition 5
([20]). Two functions and are said to be similarly ordered, if
Theorem 2
(Hölder-İşcan inequality [21]). Let and . If and are real functions defined on interval and if are integrable functions on , then
Theorem 3
(Improved power-mean integral inequality [22]). Let . If and are real functions defined on interval and if are integrable functions on , then
Owing to the aforementioned trend and inspired by the ongoing activities, the rest of this paper is organized as follows. First of all, in Section 3, we define and explore the newly introduced idea about generalized convex functions and their algebraic properties. In Section 4, we present the novel version of Hermite–Hadamard type inequality. In Section 5, we establish two new equalities and employing these new equalities and with the help of newly introduced definition, we present some refinements of Hermite–Hadamard type inequality. Finally, we give some applications in support of the newly introduced idea and a brief conclusion.
3. Generalized –Type Convex Function of Raina Type and Its Properties
In this section, we are to add and introduce a new notion for a new family of convex functions namely generalized s-type convex function of Raina type.
Definition 6.
Let be a nonempty generalized convex set with respect to . Then the nonnegative function is said to be generalized s-type convex function of Raina type, if
holds for every , , , and .
Remark 2.
Taking in Definition 6, then we attain a definition which is called generalized convex function which is first time explored by Cortez [6,7].
Taking in Definition 6, then we attain s-type convex function which is explored by İşcan et al. [19].
Taking and in Definition 6, then we obtain the convex function which is investigated by Niculescu et al. [5].
Lemma 1.
The following inequalities
are holds, if for all and .
Proof.
The rest of the proof is clearly seen. □
Proposition 1.
Every nonnegative generalized convex function of Raina type is s-type preinvex function for
Proof.
By using Lemma 1 and definition of generalized convex function of Raina type for we have
□
Proposition 2.
Every non-negative generalized s-type convex function of Raina type for is an generalized h–convex function of Raina type with .
Proof.
Using the definition of generalized s-type convex function of Raina type for and mention condition , we have
□
This means that, the new class of generalized s-type convex function of Raina type is very larger with respect to the known class of functions, like generalized convex functions and convex functions. This is the beauty of the proposed new Definition 6.
Now, we will discuss and explore the some properties in the support of the newly introduced idea.
Theorem 4.
Let If be two generalized s-type convex function of Raina type with respect to same , then
- is a generalized s-type convex function of Raina type with respect to .
- For , then is a generalized s-type convex function of Raina type with respect to .
Proof.
Let be generalized s-type convex function of Raina type with respect to same , then for all and we have
Let be a generalized s-type convex function of Raina type with respect to , then for all , and we have
This is the required proof. □
Remark 3.
Choosing in Theorem 4, then we get the and are generalized convex functions of Raina type.
Choosing in Theorem 4, then we get the and are s-type convex functions.
Choosing and in Theorem 4, then we get the and are convex functions.
Theorem 5.
Let be a generalized s-type convex function of Raina type with respect to and is non-decreasing function. Then the function is a generalized s-type convex function of Raina type with respect to same .
Proof.
For all and we have
This is the required proof. □
Remark 4.
If in Theorem 5, then
If we put in Theorem 5, then
Theorem 6.
Let be a class of generalized s-type convex function of Raina type with respect to same and . Then is a generalized s-type convex function of Raina type with respect to and is an interval.
Proof.
Let , and then
This is the required proof. □
Theorem 7.
Let If be two generalized s-type convex function of Raina type with respect to same and are similarly ordered functions and then the product is a generalized s-type convex function of Raina type with respect to .
Proof.
Let be a generalized s-type convex function of Raina type with respect to same , and then
This shows that the product of two generalized s-type convex function of Raina type with respect to same is again a generalized s-type convex function of Raina type with respect to . □
Remark 5.
Taking in Theorem 7, then we attain the new inequality namely the product of s-type convex functions
4. Hermite–Hadamard Type Inequality via Generalized s–Type Convex Function of Raina Type
The principal intention and main aim of this section is to establish novel version of Hermite–Hadamard type inequality in the mode of newly discussed concept namely generalized s-type convex function of Raina type.
Theorem 8.
Let be a generalized s-type convex function of Raina type, if and and satisfies Condition 1 then the following Hermite–Hadamard type inequalities hold
Proof.
Since and is a generalized convex set with respect to , for every and we have . From the definition of s-type preinvex function of , we have
but,
so,
This completes the right hand side of above inequality. For the left hand side we use the Definition 6, put and condition C for and integrating over ,
Putting and in above inequality, we prove the L.H.S of above inequality
So after putting the value of x and y, we get
Now by using Condition 1, we have
Now
This is the required proof. □
Corollary 1.
If we put and in Theorem 8, then we get Hermite–Hadamard inequality in [23].
Remark 6.
Under the assumption of Theorem 8, if we take with , we get the following inequality involving classical Mittag–Leffler function
5. Refinements of Hermite–Hadamard Type Inequality
The aim of this section is to investigate the refinements of Hermite–Hadamard type inequality by using the newly introduced definition. In order to attain the refinements of Hermite–Hadamard inequality, we need the following lemmas.
Lemma 2.
Let be a generalized convex subset with respect to and with . Suppose that is a differentiable function. If is integrable on the , then the following equality holds:
Proof.
Suppose that . Since X is generalized convex set with respect to , for every , we have . Integrating by parts implies that
Which completes the proof. □
Lemma 3.
Let be a generalized convex subset with respect to and with . Suppose that is a differentiable function. If is integrable on the , then the following equality holds:
Proof.
Suppose that . Since X is generalized convex set with respect to , for every , we have . Integrating by parts implies that
In this way the proof is completed. □
Theorem 9.
Suppose is a generalized convex set with respect to and be a differentiable mapping on , with and suppose that . If is a generalized s-type convex function of Raina type on , then
holds.
Proof.
Suppose that . Since is a generalized convex set with respect to , for any we have .
Using Lemma 2, one has
Since, is generalized s-type convex function of Raina type on , we have
Since,
The proof of the theorem is completed by using the above computations in (10). □
Corollary 2.
If we choose , then we attain the following inequality
Corollary 3.
If we choose , then we attain the following inequality
Corollary 4.
If we choose and , then we attain the following inequality
Remark 7.
Under the assumption of Theorem 9, if we take with , we get the following inequality involving classical Mittag–Leffler function
Theorem 10.
Suppose is a generalized convex set with respect to and be a differentiable mapping on , with and suppose that . If is generalized s-type convex function of Raina type on , then
Proof.
Suppose that . Since is a generalized convex set with respect to , for any we have .
Using Lemma 2 and Hölder’s inequality, one has
Since, is generalized s-type convex function of Raina type on , we have
Now, Equation (11) becomes
Since,
The proof of the Theorem is completed by using the above computations in (12). □
Corollary 5.
If we choose , then we attain the following inequality:
Corollary 6.
If we choose , then we attain the following inequality:
Corollary 7.
If we choose and , then we attain the following inequality:
Remark 8.
Under the assumptions of Theorem 10, if we take with , we get the following inequality involving classical Mittag–Leffler function:
Theorem 11.
Suppose is a generalized convex set with respect to and be a differentiable mapping on , with and suppose that . If is generalized s-type convex function of Raina type on , then
Proof.
Suppose that . Since is a generalized convex set with respect to , for any we have .
Using Lemma 2 and Hölder’s inequality, one has
Since is generalized s-type convex function of Raina type on , we have
Now, Equation (13) becomes
Since,
The proof of the theorem gets completed by using the above computations in (14). □
Corollary 8.
If we choose , then we attain the following inequality
Corollary 9.
If we choose , then we attain the following inequality,
Corollary 10.
If we choose and , then we attain the following inequality,
Remark 9.
Under the assumptions of Theorem 11, if we take with , we get the following inequality involving classical Mittag–Leffler function,
Theorem 12.
Suppose is a generalized convex set with respect to and be a differentiable mapping on , with and suppose that . If is generalized s-type convex function of Raina type on , then
Proof.
Suppose that . Since, is a generalized convex set with respect to , for any we have .
Using Lemma 2 and Hölder-Íscan inequality, one has
Since, is generalized s-type convex function of Raina type on , we have
Now, Equation (15) becomes
Since,
The proof of the Theorem is completed by using the above computations in (16). □
Corollary 11.
If we choose , then we attain the following inequality,
Corollary 12.
If we choose , then we attain the following inequality:
Corollary 13.
If we choose and , then we attain the following inequality:
Remark 10.
Under the assumptions of Theorem 12, if we take with , we get the following inequality involving classical Mittag–Leffler function,
Theorem 13.
Suppose is a generalized convex set with respect to and be a differentiable mapping on , with and suppose that . If is a generalized s-type convex function of Raina type on , then
Proof.
Suppose that . Since is a generalized convex set with respect to , for any we have .
Using Lemma 2 and Improved power-mean inequality, one has
Since is generalized s-type convex function of Raina type on , we have
Since,
The proof of the theorem is completed by using the above computations in (18). □
Corollary 14.
If we choose , then we attain the following inequality:
Corollary 15.
If we choose , then we attain the following inequality:
Corollary 16.
If we choose and , then we attain the following inequality:
Remark 11.
Under the assumptions of Theorem 13, if we take with , we get the following inequality involving classical Mittag–Leffler function,
Theorem 14.
Suppose is a generalized convex set with respect to and be a differentiable mapping on , with and suppose that . If is generalized s-type convex function of Raina type on , then
Proof.
Suppose that . Since is a generalized convex set with respect to , for any we have .
Using Lemma 2 and Power-mean inequality, one has
Since, is generalized s-type convex function of Raina type on , we have
Now, Equation (19) becomes
Since,
The proof of the theorem gets completed by using the above computations in (20). □
Corollary 17.
If we choose , then we attain the following inequality:
Corollary 18.
If we choose , then we attain the following inequality:
Corollary 19.
If we choose and , then we attain the following inequality:
Remark 12.
Under the assumptions of Theorem 14, if we take with , we get the following inequality involving classical Mittag–Leffler function:
Theorem 15.
Suppose is a generalized convex set with respect to and be a differentiable mapping on , with and suppose that . If is generalized s-type convex function of Raina type on , then
Proof.
Suppose that . Since is a generalized convex set with respect to , for any we have .
Using Lemma 3 and Hölder’s inequality, one has
□
Corollary 20.
If we choose , then we attain the following inequality:
Corollary 21.
If we choose , then we attain the following inequality:
Corollary 22.
If we choose and , then we attain the following inequality:
Remark 13.
Under the assumption of Theorem 15, if we take with , we get the following inequality involving classical Mittag–Leffler function,
Theorem 16.
Suppose is a generalized convex set with respect to and be a differentiable mapping on , with and suppose that . If is generalized s-type convex function of Raina type on , then
Proof.
Suppose that . Since is a generalized convex set with respect to , for any we have .
Using Lemma 3 and power-mean inequality, one has
□
Corollary 23.
If we choose , then we attain the following inequality:
Corollary 24.
If we choose , then we attain the following inequality:
Corollary 25.
If we choose and , then we attain the following inequality:
Remark 14.
Under the assumption of Theorem 16, if we take with , we get the following inequality involving classical Mittag–Leffler function:
6. Applications to Special Means
In this section, we recall the following special means of two positive numbers with :
- (1)
- The arithmetic mean
- (2)
- The geometric mean
- (3)
- The harmonic mean
The following relationship is well-known in the literature.
Proposition 3.
Let and . then
Proof.
We attain the above inequality (21), if we put for in Theorem 8. □
Proposition 4.
Let with and , then
Proof.
We attain the above inequality (22), if we put for in Theorem 8. □
Remark 15.
Under the assumption of Proposition 4, if we take with , we get the following inequality involving classical Mittag–Leffler function:
Proposition 5.
Let with and , then
Proof.
We attain the above inequality (24), if we put for in Theorem 8. □
Remark 16.
Under the assumption of Proposition 5, if we take with , we get the following inequality involving classical Mittag–Leffler function:
7. Conclusions
In this article, we addressed a novel idea for the generalized preinvex function, namely the s-type preinvex function. Some algebraic properties were examined concerning the proposed definition. In the manner of the newly proposed definition, we described the novel version of Hermite–Hadamard type inequality. Further, we made two new lemmas. Our attained results in the order of new lemmas can be considered as refinements and remarkable extensions to the new family of preinvex functions. Our novel results can be deduced from the previously known results. Applications to special means were considered. In addition we made some comments; the above estimations on the mentioned lemmas need an interesting and amazing comparison. On Lemma 2, we examined three Theorems 10–12, in which we used the Hölder and Hölder-İ scan inequality. In comparison, Theorem 12 gives a better result as compared to the other Theorems 10 and 11. Similarly, On Lemma 2, we examined two Theorems 13 and 14, in which we used power mean and improved power mean inequality. In comparison, Theorem 13 gives a better result as compared to the other Theorem 14. We hope the consequences and techniques of this article will energize and inspire researchers to explore a more interesting sequel in this area.
Author Contributions
Conceptualization, H.A., M.T. and S.K.S.; methodology, M.T., S.K.S. and C.C.; software, H.A., M.T. and S.K.S.; validation, H.A., M.T., S.K.S., J.B. and C.C.; investigation, H.A., M.T., S.K.S., J.B. and C.C.; writing—original draft preparation, H.A., M.T. and S.K.S.; writing—review and editing, M.T. and S.K.S.; supervision, H.A., J.B., C.C. All authors have read and agreed to the final version of the manuscript.
Funding
This research work was supported by the Deanship of Scientific Research at King Khalid University under Grant number RGP. 1/387/42.
Institutional Review Board Statement
Not applicable.
Informed Consent Statement
Not applicable.
Data Availability Statement
No data were used to support this study.
Acknowledgments
The Authors extend their thanks to the Deanship of Scientific Research at King Khalid University for funding this work through the small research groups under grant number RGP. 1/387/42.
Conflicts of Interest
The authors declare that there are no conflict of interest regarding the publication of this paper.
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