Abstract
This paper presents a novel approach by introducing a set of operators known as the left and right generalized tempered fractional integral operators. These operators are utilized to establish new Hermite–Hadamard inequalities for convex functions as well as the multiplication of two convex functions. Additionally, this paper gives two useful identities involving the generalized tempered fractional integral operator for differentiable functions. By leveraging these identities, our results consist of integral inequalities of the Hermite–Hadamard type, which are specifically designed to accommodate convex functions. Furthermore, this study encompasses the identification of several special cases and the recovery of specific known results through comprehensive research. Lastly, this paper offers a range of applications in areas such as matrices, modified Bessel functions and -digamma functions.
1. Introduction
Convexity theory is a fundamental concept in mathematical analysis that plays a crucial role in various fields, including optimization, economics, and geometry. It provides a powerful framework for studying and analyzing functions and their properties. In particular, convex functions possess significant characteristics that make them exceptionally useful in many applications.
The Hermite–Hadamard inequality [1] (H–H for short) stands as a fundamental outcome within the realm of convexity theory that establishes a relationship between the average value of a convex function and its endpoint values. Named after Charles Hermite and Jacques Hadamard, this inequality provides a powerful tool for studying the behaviour of convex functions and their integrals. It has been widely investigated and extended to various contexts, making it an essential tool in mathematical analysis. Over the years, researchers have made significant contributions to the development and generalization of the H–H inequality. These efforts have led to the exploration of various generalizations, extensions, and refinements of the original inequality, involving different types of functions, operators, and integral formulations; for example, Bayraktar et al. [2] proved Mercer versions, Sahoo et al. [3] established H–H inequalities via Atangana–Baleanu fractional operators, Tariq et al. [4] presented Simpson–Merer-type inequalities with the help of Atangana–Baleanu fractional operators, and for new versions of H–H results involving exponential kernels, one can refer to [5] and Bayraktar et al. [6], who employed a modified (h,m,s) convex function to establish weighted H–H inequalities. These advancements have broadened the scope of the H–H inequality and deepened our understanding of convex functions.
In this research paper, we aim to contribute to the ongoing development of convexity theory and the H–H inequality. Our focus will be on introducing new operators, namely the left and right generalized tempered fractional integral operators, and their applications in establishing novel H–H inequalities. These operators offer a fresh perspective on the interplay between convex functions and integral inequalities.
Additionally, we will derive two useful identities for differentiable functions that involve the generalized tempered fractional integral operator. We will explore various special cases and demonstrate how our general results recover known results. Moreover, we will showcase the practical relevance and applications of our findings. In particular, we will delve into applications encompassing matrices, modified Bessel functions, and -digamma functions. By examining these applications, we aim to highlight the significance and versatility of convexity theory and the H–H inequality in solving real-world problems.
Overall, this research paper aims to contribute to the advancement of convexity theory and the H–H inequality by introducing new operators, establishing novel inequalities, deriving interesting identities, exploring special cases, and demonstrating practical applications. Through our work, we hope to deepen our understanding of convex functions and their properties, paving the way for further advancements in this research area of mathematical analysis. Let us denote with an interval that is a subset of the set of real numbers
Definition 1.
A function is called convex, if
holds for all and
Theorem 1.
(H–H inequality). For a convex function and two points with , the following double inequality is valid:
In recent decades, researchers have investigated inequality (2) using newly formulated definitions motivated by convex functions. For further exploration, interested readers can refer to the following sources: [7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22].
Definition 2.
For any real number and , the ζ-incomplete gamma function is defined as
If , then the above function reduces to the incomplete gamma function
In the following sections, we will revisit the definition of tempered fractional integral operators.
Definition 3
([22]). Let (the set of all Lebesgue integrable functions on , where Then for the tempered fractional integral operators and of order are defined as
and
respectively.
Taking in Definition 3, we obtain Riemann–Liouville fractional integral operators defined by
and
The function was introduced by Sarikaya et al. in [18], characterized by the following conditions:
where are independent of If there exists a non-negative value of such that is an increasing function, and there exists a non-negative value of such that is a decreasing function, then it can be deduced from [23] that satisfies (7)–(10). Based on this, the definitions of the left-sided and right-sided generalized integral operators are given as follows:
A notable feature of generalized integrals is their ability to yield Riemann–Liouville fractional integrals, Katugampola fractional integrals, and other types as well. These results can be found in references such as [18,20,23,24].
In recent years, there has been a growing interest in extending the H–H inequality to the context of fractional calculus. Fractional calculus deals with the generalization of derivatives and integrals to non-integer orders, and it has emerged as a powerful mathematical tool for modeling and analyzing complex phenomena in physics, engineering, and other fields. The fractional H–H inequality explores the behavior of fractional integrals of convex functions. By considering fractional operators of different orders, such as the Riemann–Liouville or Caputo fractional operators, the inequality provides a bridge between the concepts of convexity and fractional calculus. It establishes relationships between the fractional integral of a convex function and its endpoint values, revealing intriguing properties and insights into the behavior of these functions. The study of fractional H–H inequalities has attracted significant attention from researchers in recent years. Many mathematicians have worked on deriving new inequalities, investigating their properties, and exploring their applications in various areas [25,26]. These developments have led to a deeper understanding of the interplay between convex functions and fractional calculus.
In Section 2, we begin by introducing the left and right generalized tempered fractional integral operators as novel tools in the study of H–H inequalities. By utilizing these operators, we establish novel inequalities for convex functions as well as for products of two convex functions. These results extend the existing literature and provide valuable insights into the behavior of convex functions.
Moving on to Section 3, we delve into the exploration of two interesting identities involving the generalized tempered fractional integral operators for differentiable functions. Through the utilization of these identities, we obtain supplementary integral inequalities of H–H and midpoint types for convex functions. This further expands the scope and applicability of our findings.
Section 4 takes a practical turn as we delve into the application of our results. We discuss their relevance and implications in various domains, such as matrices, modified Bessel functions and -digamma functions.
Finally, in Section 5, we wrap up the paper with a concise conclusion summarizing the key findings and their implications. We also provide future recommendations, suggesting potential directions for further research.
Through this structured organization, our paper presents a comprehensive analysis of the introduced operators, establishes new inequalities, explores intriguing identities, demonstrates practical applications, and offers valuable insights for future research.
2. Generalized Tempered Fractional Hermite–Hadamard-Type Inequalities
At this point, we can present the left and right generalized tempered fractional integral operators with , where satisfies the given conditions (7)–(10).
Throughout this study, let and Then, for all we define the following definitions:
Definition 4.
The operator that defines the left generalized tempered fractional integral is given by
Analogously, the right generalized tempered fractional integral operator is defined by
From Definition 4, we can recapture some known integral operators such as Riemann integrals, Riemann–Liouville fractional integrals, generalized integral operators, and tempered fractional integral operators, and we can present some new integral operators as well. Some of them are given explicitly in the following Remark 1. Moreover, the importance of these new integral operators depends on the choices of the parameter since it takes values in the domain That means that interested readers that will do numerical computations will see clearly the advantage of this new operator compared with other known operators for suitably choosing this parameter For these operators attains maximum values. For other values of their values decrease. We believe that these new operators will open a new door for investigating various variational problems for different kinds of convexity functions. In our study, we are not focused on numerical analysis.
Remark 1.
- (a)
- (b)
- Choosing for in Definition 4, we obtain the following conformable left and right tempered fractional integral operators:Taking where for in Definition 4, we have the following exponential left and right tempered fractional integral operators:
Furthermore, we define the following expressions that will be used in the sequel.
and
Let us now represent the generalized tempered fractional H–H-type inequality for convex functions as follows.
Theorem 2.
Consider a function defined on the interval and . If is convex on , then the following double inequality holds true for generalized tempered fractional integral operators:
where is defined from (18).
Proof.
Let Since is convex on we have
Taking and we get
By multiplying both sides of inequality (20) with the expression and integrating the resulting inequality over the interval with respect to , we derive the following result
So, we have
This implies that the left-hand side of inequality (19) has been established. In order to prove the right-hand side of inequality (19), we utilize the fact that is a convex function on . This allows us to derive the following inequalities:
and
Multiplying both sides of inequality (24) with and integrating the resulting inequality with respect to t over we obtain
Therefore, we have the following inequality:
This confirms that the right-hand side of inequality (19) has been established. Therefore, the proof of Theorem 2 is concluded. □
Corollary 1.
By taking in Theorem 2, we obtain the following double inequality for convex functions using tempered fractional integral operators:
Corollary 2.
Choosing and in Corollary 1, we get Theorem 1.
Theorem 3.
Let be two functions and If and are convex on then the following double inequality for generalized tempered fractional integral operators holds true:
where
and is defined from (18).
Proof.
Let Since and are convex on we have
Taking and we get
and
Multiplying both sides of inequality (30) with and integrating the resulting inequality with respect to over we have
So, we get
This implies that the left-hand side of inequality (27) has been established. In order to prove the right-hand side of inequality (27), we utilize the fact that and are both convex functions on . This allows us to derive the following inequalities:
and
Multiplying both sides of inequality (36) with and integrating the resulting inequality with respect to over we obtain
So, we get
This implies that the right-hand side of inequality (27) has been established. Therefore, the proof of Theorem 3 is concluded. □
Corollary 3.
By substituting into Theorem 3, we obtain the following result:
where
and
Corollary 4.
By selecting in Theorem 3, we derive the following double inequality for the product of two convex functions employing tempered fractional integral operators:
where
and
3. Further Results Related to Generalized Tempered Fractional Integral Operators
To establish the results of this section regarding generalized tempered fractional integral operators, we commence by proving the following two lemmas.
Lemma 1.
Proof.
By performing integration by parts on Equation (43) and making a change of variables in the integration, we obtain
Similarly, using (44), we get
Remark 2.
Taking and in Lemma 1, we get ([19], Lemma 3.1).
Lemma 2.
Proof.
The proof is similar to the proof of Lemma 1. □
Theorem 4.
Assume that is a differentiable function on the interval . If and is a convex function, then, under the conditions and , the following inequality holds true for generalized tempered fractional integral operators:
where
Proof.
Based on the properties of modulus, the convexity of and applying Hölder’s inequality, we can deduce from Lemma 1 the following results:
We have successfully completed the proof of Theorem 4. □
Let us highlight a few specific scenarios that arise as special cases of Theorem 4.
Corollary 5.
Taking and in Theorem 4, we get ([19], Corollary 3.3).
Corollary 6.
Choosing in Theorem 4, we obtain
Theorem 5.
Consider a differentiable function defined on the interval . Suppose and is a convex function. Then, for , the following inequality holds true for generalized tempered fractional integral operators:
where
and is defined from (18).
Proof.
From Lemma 1, convexity of power mean inequality and properties of the modulus, we have
We have successfully completed the proof of Theorem 5. □
Now, let us consider some specific instances that arise as special cases of Theorem 5.
Corollary 7.
Taking in Theorem 5, we have
Corollary 8.
Choosing and in Corollary 7, we get ([19], Theorem 1.4).
Corollary 9.
By employing the inequality in Theorem 5, we can derive the following result,
Theorem 6.
Consider a differentiable function defined on the interval . Suppose and is a convex function. Then, under the conditions and , the following inequality holds true for the generalized tempered fractional integral operators:
where
Proof.
By utilizing Lemma 2, convexity of , Hölder’s inequality and considering the properties of the modulus, we can derive the following results:
The proof of Theorem 6 has been successfully concluded. □
Let us highlight certain specific instances of Theorem 6.
Corollary 10.
By substituting into Theorem 6, we obtain the following midpoint inequality using generalized tempered fractional integral operators:
where
Corollary 11.
Choosing in Theorem 6, we get
where
Corollary 12.
By substituting into Theorem 6, we derive the following result:
Theorem 7.
For a differentiable function defined on the interval if and the function is convex, where then the following inequality holds true for the generalized tempered fractional integral operators:
where
and is defined from (18).
Proof.
From Lemma 2, convexity of power mean inequality and properties of the modulus, we have
The proof of Theorem 7 is completed. □
We point out some special cases of Theorem 7.
Corollary 13.
Taking in Theorem 7, we have
Corollary 14.
Choosing in Theorem 7 and utilizing the generalized tempered fractional integral operators, we obtain the following midpoint inequality:
where
Corollary 15.
Taking in Theorem 7, we obtain
where
Corollary 16.
Choosing in Theorem 7, we have
Remark 3.
Applying our results for suitable choices of function and where for such that to be convex function, we can construct some new tempered fractional integral type inequalities. We omit their proofs and the details are left to the interested readers.
4. Applications
In the final section, we provide several examples that illustrate the results we have established in relation to matrices, modified Bessel functions and -digamma function.
4.1. Matrices
Example 1.
In this context, the set of complex matrices is denoted by Similarly, represents the algebra of complex matrices and refers to the subset of strictly positive matrices within Consequently, for a matrix it holds that for all nonzero
Incorporating the concepts of matrices and convexity, Sababheh [27] introduced the function , where and . It was shown that this function is convex for all . Consequently, by utilizing Theorem 2 for any , we obtain
4.2. Modified Bessel Functions
The modified Bessel function of the first kind, denoted as , is a mathematical function defined as the following infinite sum:
where is a real number and .
The modified Bessel function of the second kind, denoted as , is defined in terms of as follows:
Another function, , can be defined as:
where represents the gamma function.
In the cited reference [28], two derivative formulas for are given. The first derivative is expressed as:
The second derivative is given by:
Proof.
4.3. -Digamma Function
The -digamma function, denoted as , is a function that serves as the -analogue of the digamma function . The formula for is provided in the references [28,29] and is given as follows:
or alternatively,
This expression holds true when and . The -digamma function can also be expressed in the following form:
or alternatively,
Example 4.
Applying Corollary 7, we have
Proof.
The statement can be readily derived by utilizing Corollary 7, where represents a completely monotone function on the interval for all . As a result, is a convex function. □
Example 5.
Using Corollary 13, we get
Proof.
The assertion can be immediately derived by utilizing Corollary 13, where represents a completely monotone function on the interval for all . Consequently, is a convex function. □
5. Conclusions
Overall, this paper aimed to contribute to the expanding field of fractional H–H inequalities by presenting new results, exploring their properties, investigating their connections with fractional calculus, and demonstrating their applications. Through our work, we sought to advance the theoretical foundations of fractional calculus, enhance our understanding of convex functions in the fractional calculus framework, and inspire further research in this exciting and evolving area of mathematics.
This research paper introduces novel concepts of left and right generalized tempered fractional integral operators and establishes fresh H–H inequalities for convex functions and their products. Additionally, it derives two useful identities for differentiable functions that involve the generalized tempered fractional integral operator. These identities are then utilized to establish H–H and midpoint-type integral inequalities for convex functions. The paper also explores various special cases and demonstrates how the general findings recover known results. Furthermore, the paper presents compelling applications related to matrices, modified Bessel functions and -digamma functions. By employing the newly introduced generalized tempered fractional integral operators, along with well-known inequalities such as Hölder–İşcan’s inequality, Improved-Power-mean’s inequality, Young’s inequality, Minkowski’s inequality, and Chebyshev’s inequality, this paper establishes novel bounds for differentiable convex functions. Finally, the importance of these new integral operators depends on the choices of the parameter since it takes values in the domain In other words, interested readers that will do numerical computations will immediately see the advantage of this new operator compared with other known integral operators in terms of the suitable choices of parameter We believe that these new operators will be important tools for investigating various variational problems for different types of convexities.
Author Contributions
Conceptualization, A.K., S.K.S., A.M.M. and Y.A.; methodology, A.K., S.K.S. and A.M.M.; software, S.K.S. and Y.A.; validation, A.K., A.M.M. and S.K.S.; project administration, S.K.S.; writing—original draft preparation, A.K. and S.K.S.; writing—review and editing, A.K., S.K.S., A.M.M. and Y.A. All authors have read and agreed to the published version of the manuscript.
Funding
This research received no external funding.
Data Availability Statement
Not applicable.
Acknowledgments
The authors extend their appreciation to the Deanship of Scientific Research at King Khalid University for funding this work through the large group research project under grant number RGP2/366/44.
Conflicts of Interest
The authors declare no conflict of interest.
References
- Hadamard, J. Étude sur les propriétés des fonctions entières en particulier d’une fonction considérée par Riemann. J. Math. Pures Appl. 1893, 58, 171–215. [Google Scholar]
- Bayraktar, B.; Kórus, P.; Valdés, J.E.N. Some new Jensen-Mercer type integral inequalities via fractional operators. Axioms 2023, 12, 517. [Google Scholar] [CrossRef]
- Sahoo, S.K.; Jarad, F.; Kodamasingh, B.; Kashuri, A. Hermite-Hadamard type inclusions via generalized Atangana-Baleanu fractional operator with application. AIMS Math. 2022, 7, 12303–12321. [Google Scholar] [CrossRef]
- Tariq, M.; Ahmad, H.; Sahoo, S.K.; Kashuri, A.; Nofal, T.A.; Hsu, C.H. Inequalities of Simpson-Mercer-type including Atangana-Baleanu fractional operators and their applications. AIMS Math. 2022, 7, 15159–15181. [Google Scholar] [CrossRef]
- Kashuri, A.; Sahoo, S.K.; Mohammed, P.O.; Sarairah, E.A.; Hamed, Y.S. Some new Hermite-Hadamard type inequalities pertaining to fractional integrals with an exponential kernel for subadditive functions. Symmetry 2023, 15, 748. [Google Scholar] [CrossRef]
- Bayraktar, B.; Nápoles, J.E.; Rabossi, F. Some refinements of the Hermite–Hadamard inequality with the help of weighted integrals. Ukr. Mat. Zhurnal 2023, 75, 736–752. [Google Scholar] [CrossRef]
- Aslani, S.M.; Delavar, M.R.; Vaezpour, S.M. Inequalities of Fejér type related to generalized convex functions with applications. Int. J. Anal. Appl. 2018, 16, 38–49. [Google Scholar]
- Delavar, M.R.; Dragomir, S.S. On η-convexity. Math. Inequal. Appl. 2017, 20, 203–216. [Google Scholar]
- Delavar, M.R.; De La Sen, M. Some generalizations of Hermite-Hadamard type inequalities. SpringerPlus 2016, 5, 1661. [Google Scholar] [CrossRef]
- Dragomir, S.S.; Agarwal, R.P. Two inequalities for differentiable mappings and applications to special means of real numbers and trapezoidal formula. Appl. Math. Lett. 1998, 11, 91–95. [Google Scholar] [CrossRef]
- Jleli, M.; Samet, B. On Hermite-Hadamard type inequalities via fractional integral of a function with respect to another function. J. Nonlinear Sci. Appl. 2016, 9, 1252–1260. [Google Scholar] [CrossRef]
- Kashuri, A.; Liko, R. Some new Hermite-Hadamard type inequalities and their applications. Stud. Sci. Math. Hung. 2019, 56, 103–142. [Google Scholar]
- Liu, W.; Wen, W.; Park, J. Hermite-Hadamard type inequalities for MT-convex functions via classical integrals and fractional integrals. J. Nonlinear Sci. Appl. 2016, 9, 766–777. [Google Scholar]
- Mihai, M.V. Some Hermite-Hadamard type inequalities via Riemann-Liouville fractional calculus. Tamkang J. Math. 2013, 44, 411–416. [Google Scholar] [CrossRef]
- Omotoyinbo, O.; Mogbodemu, A. Some new Hermite-Hadamard integral inequalities for convex functions. Int. J. Sci. Innov. Technol. 2014, 1, 1–12. [Google Scholar]
- Özdemir, M.E.; Dragomir, S.S.; Yildiz, C. The Hadamard’s inequality for convex function via fractional integrals. Acta Math. Sci. 2013, 33, 153–164. [Google Scholar] [CrossRef]
- Qi, F.; Mohammed, P.O.; Yao, J.C.; Yao, Y.H. Generalized fractional integral inequalities of Hermite-Hadamard type for (α,m)-convex functions. J. Inequal. Appl. 2019, 135, 17. [Google Scholar] [CrossRef]
- Sarikaya, M.Z.; Ertuğral, F. On the Generalized Hermite-Hadamard Inequalities. 2017, p. 20. Available online: https://www.researchgate.net/publication/321760443 (accessed on 21 June 2023).
- Set, E.; Gözpinar, A. A study On Hermite-Hadamard type inequalities for s-convex functions via conformable fractional integrals. Stud. Univ. Babeş-Bolyai Math. 2017, 62, 309–323. [Google Scholar] [CrossRef]
- Set, E.; Noor, M.A.; Awan, M.U.; Gözpinar, A. Generalized Hermite-Hadamard type inequalities involving fractional integral operators. J. Inequal. Appl. 2017, 169, 10. [Google Scholar] [CrossRef]
- Xi, B.Y.; Qi, F. Some integral inequalities of Hermite-Hadamard type for convex functions with applications to means. J. Funct. Spaces Appl. 2012, 2012, 980438. [Google Scholar] [CrossRef]
- Mohammed, P.O.; Sarikaya, M.Z.; Baleanu, D. On the generalized Hermite-Hadamard inequalities via the tempered fractional integrals. Symmetry 2020, 12, 595. [Google Scholar] [CrossRef]
- Sarikaya, M.Z.; Yildirim, H. On generalization of the Riesz potential. Indian J. Math. Math. Sci. 2007, 3, 231–235. [Google Scholar]
- Katugampola, U.N. New approach to a generalized fractional integral. Appl. Math. Comput. 2011, 218, 860–865. [Google Scholar] [CrossRef]
- Fahad, A.; Butt, S.I.; Bayraktar, B.; Anwar, M.; Wang, Y. Some new Bullen-type inequalities obtained via fractional integral operators. Axioms 2023, 12, 691. [Google Scholar] [CrossRef]
- Latif, M.A.; Kalsoom, H.; Khan, Z.A.; Al-moneef, A.A. Refinement mappings related to Hermite-Hadamard type inequalities for GA-convex function. Mathematics 2022, 10, 1398. [Google Scholar] [CrossRef]
- Sababheh, M. Convex functions and means of matrices. Math. Inequal. Appl. 2017, 20, 29–47. [Google Scholar] [CrossRef]
- Watson, G.N. A Treatise on the Theory of Bessel Functions; Cambridge University Press: Cambridge, UK, 1995. [Google Scholar]
- Jain, S.; Mehrez, K.; Baleanu, D.; Agarwal, P. Certain Hermite-Hadamard inequalities for logarithmically convex functions with applications. Mathematics 2019, 7, 163. [Google Scholar] [CrossRef]
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