Abstract
For all convex functions, the Hermite–Hadamard inequality is already well known in convex analysis. In this regard, Hermite–Hadamard and Ostrowski type inequalities were obtained using exponential type convex functions in this work. In addition, new generalizations were found for different values of . In conclusion, we believe that our work’s technique will inspire more study in this field.
MSC:
26A15; 26A51; 26D10
1. Introduction
The Hermite–Hadamard inequality, which is a major result of the widespread use and great geometrical interpretation of convex functions, has attracted a lot of attention in fundamental mathematics. Recent years have seen remarkable advancement in the inequality field [1,2,3,4]. One of the most significant causes of this development is significant inequalities, such as the Hermite–Hadamard inequality. It is interesting considering how closely connected the theories of inequality and convexity are to one another. The theory of novel convexity has received various new extensions, refinements, and definitions in recent years, and corresponding advancements in the theory of convexity inequality, especially integral inequalities theory, have also been addressed.
The definition of the convex function can be represented as follows:
Definition 1.
A function is said to be convex if
holds for all and .
The Hermite–Hadamard inequality is formally expressed as follows:
We let be a convex function on the interval I of real numbers and with .
The inequality in (1) holds in reverse directions if is a concave function. The geometry-based Hermite–Hadamard inequality provides an upper and lower estimate for the integral mean of any convex function defined on a closed and limited domain, which includes the function’s endpoints and midpoint. Due to the significance of this inequality, several variations of the Hermite–Hadamard inequality have been examined in the literature for various classes of convexity, including harmonically convex, exponentially convex, s-convex, h-convex, and co-ordinate convex functions [5,6,7,8,9].
In 1938, the classical integral inequality was established by Ostrowski as follows:
Theorem 1.
Let be a differentiable mapping on whose derivative is bounded on , i.e., . Then, the following inequality is obtained:
for all . The constant is the best possible.
In the theory of inequality, convex functions play a fundamental role. Various definitions of convex functions have been the subject of investigations by numerous authors. Previous studies have focused on convexity types such as quasi-convex, p-convex, m-convex, -convex and especially s-convex. However, recent studies have found that many new types of convexity have been obtained. The exponential type convex functions is one of these new forms of convexity. We provide the following new definition:
Definition 2
([10]). A nonnegative function is called exponential type convex function if, for every and ,
The class of all exponential type convex functions on interval I is demonstrated by .
In [10], the exponential type convex functions has been described by Kadakal and İşcan, and additional inequalities based on this definition have been established. With this definition, researchers have defined different types of convexities (such as exponential trigonometric convex, exponentially convex, exponentially tgs-convex, exponentially -convex, exponentially -convex in [11,12,13,14,15,16,17,18,19]) and obtained new inequalities:
Remark 1
([10]). The range of the exponential type convex functions is .
Lemma 1
([10]). For all , inequalities and hold.
Proposition 1
([10]). Every nonnegative convex function is exponential type convex function.
Also in [10], using this definition, Kadakal and İşcan obtained new integral inequalities as follows:
Theorem 2.
Let be an exponential type convex function. If and , then the following Hermite–Hadamard type inequalities holds:
Theorem 3.
Let be a differentiable function on (interior of I), with , and assume that . If is an exponential type convex function on ; then, the following is obtained:
Theorem 4.
Let be a differentiable function on (interior of I), with , and assume that . If is an exponential type convex function on ; then, the following is obtained:
Theorem 5.
Let be a differentiable function on (interior of I), with , and assume that . If is an exponential type convex function on ; then, the following is obtained:
Hölder inequality is the basis of many theorems and inequalities. Therefore, the authors have widely used the Hölder inequality and the power-mean inequality as a result of Hölder inequality in their research.
In [20], İşcan obtained the Hölder–İşcan inequality and showed that this inequality produces better upper bounds than the Hölder inequality. By using the Hölder–İşcan inequality, many new results were obtained in the literature (see [20,21,22,23,24,25]).
The Hölder–İşcan inequality is defined as follows in [20]:
Theorem 6.
Let and . If ϑ and ℏ are real functions defined on and if and are integrable on ; then,
The main purpose of this paper is to obtain new inequalities for exponential convex functions by using Identity (5). In line with this purpose, we achieve a new integral identity for continuously differentiable functions. This identity helps as an auxiliary result to obtain the main results of the article. Also, we obtain different types of inequalities according to different values of .
2. Main Results
First of all, we need to establish the following new lemma, which plays an important role in obtaining the main results of the article:
Lemma 2
([26]). Let be a differentiable function on (interior of I), with , and assume that (Integrable in the Lebesgue means). Then, the following is obtained:
where
Theorem 7.
Let be a differentiable function on , with , and assume that . If is an exponential type convex function on ; then, inequality
holds for , , where .
Proof.
Using identity (5) and Hölder’s inequality, we have
Therefore, is an exponential type convex function on . We obtain
This completes the proof. □
The result obtained below is related to the left-hand side of the Ostrowski inequality:
Corollary 1.
If we choose in Theorem 7, we obtain
Corollary 2.
If we choose in Corollary 1, we have the following inequality that is related to the left-hand side of Hadamard integral inequalities;
The result obtained below is a generalized version of the Hermite–Hadamard inequality.
Corollary 3.
If we choose in Theorem 7, we obtain
Corollary 4.
If we choose in Corollary 3, we have the following inequality that is related to the right-hand side of Hadamard integral inequalities for exponential-type convex functions;
Theorem 8.
Let be a differentiable function on , with , and assume that . If is an exponential type convex function on ; then, we the following inequality is obtained:
where
and , , .
Proof.
Corollary 5.
If we choose in Theorem 8, we obtain
, , μ and ω are as in Theorem 8.
Corollary 6.
If we choose in Corollary 5, we obtain the following inequality that is related to the left-hand side of Hadamard integral inequalities:
Corollary 7.
If we choose in Theorem 8, we obtain
, , μ and ω are as in Theorem 8.
Corollary 8.
If we choose in Corollary 7, we obtain the following inequality that is related to the right-hand side of Hadamard integral inequalities for exponential type convex functions:
Theorem 9.
Let be a differentiable function on , with , and assume that . If is an exponential type convex function on , then the following inequality can be obtained:
where , and
Proof.
We assume that . By using Identity (5), power-mean inequality and the property of the exponential type convex of , we obtain
Hence, we obtain
and
Also,
Thus, the proof is completed. □
Corollary 9.
Under the assumptions of Theorem 9, by choosing , we obtain
where , and
Remark 2.
If we choose in Inequality (8), we obtain the following inequality that is related to the left-hand side of Hadamard integral inequalities:
Inequality (9) is better than Inequality (2), because, for and , if we use Inequality (9), we obtain
Also, if we use Inequality (2), we can write
Therefore, Inequality (9) is better than Inequality (2).
The following new result was obtained as an Ostrowski type inequality:
Corollary 10.
If we choose in Theorem 9, we obatin
Corollary 11.
If we choose in Corollary 10, we obtain the following inequality that is related to the left-hand side of Hadamard integral inequalities:
Corollary 12.
If we choose in Theorem 9, we obtain
Corollary 13.
If we choose in Corollary 12, we obtain the following inequality that is related to the right-hand side of Hadamard integral inequalities for exponential type convex functions:
3. Conclusions
In this paper, different types of inequalities (Hermite–Hadamard Inequality, Ostrowski Inequality) were found according to different values of by using exponential type convex functions. In addition, researchers can obtain different types of inequalities according to different values of . The Hölder–İşcan inequality and several lemmas can be used to produce novel results for various kinds of convexity. We are certain that the novel consequences and approaches discussed in this paper will inspire scholars to look into a more intriguing continuation in this area. On the other hand, we believe that if we use the weighted integrals of [27,28], much more general results can be obtained.
Author Contributions
Conceptualization, Ç.Y. and J.E.N.V.; methodology, Ç.Y.; software, Ç.Y. and J.E.N.V.; validation, Ç.Y., J.E.N.V. and L.-I.C.; formal analysis, Ç.Y.; investigation, Ç.Y., J.E.N.V. and L.-I.C.; data duration, Ç.Y. and J.E.N.V.; writing—original draft preparation, Ç.Y.; writing—review and editing, Ç.Y., J.E.N.V. and L.-I.C.; visualization, Ç.Y.; supervision, Ç.Y. and J.E.N.V.; project administration, Ç.Y. and L.-I.C.; funding acquisition, L.-I.C. 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.
Conflicts of Interest
The authors declare no conflict of interest.
References
- Khan, M.A.; Chu, Y.; Khan, T.U.; Khan, J. Some new inequalities of Hermite-Hadamard type for s-convex functions with applications. Open Math. 2017, 15, 1414–1430. [Google Scholar] [CrossRef] [Scilit]
- Dragomir, S.S.; Pearce, C.E.M. Selected Topics on Hermite-Hadamard Inequalities and Applications; RGMIA Monographs; Victoria University: Sunshine North, VIC, Australia, 2000. [Google Scholar]
- 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] [Scilit]
- Sarıkaya, M.Z.; Set, E.; Yaldiz, H.; Başak, N. Hermite-Hadamard’s inequalities for fractional integrals and related fractional inequalities. Math. Comput. Model. 2013, 57, 2403–2407. [Google Scholar] [CrossRef] [Scilit]
- Dragomir, S.S.; Fitzpatrick, S. The Hadamard inequalities for s-convex functions in the second sense. Demonstr. Math. 1999, 32, 687–696. [Google Scholar] [CrossRef] [Scilit]
- Yıldız, Ç.; Yergöz, B.; Yergöz, A. On new general inequalities for s-convex functions and their applicaitons. J. Inequal. Appl. 2023, 2023, 11. [Google Scholar] [CrossRef] [Scilit]
- Rapeanu, E. Continuation method for boundary value problems with uniform elliptical operators. J. Sci. Art 2011, 3, 273–277. [Google Scholar]
- İşcan, İ. Hermite-Hadamard type inequalities for harmonically convex functions. Hacet. J. Math. Stat. 2014, 43, 935–942. [Google Scholar] [CrossRef] [Scilit]
- Rapeanu, E. Approximation by projection of some operators. Anal. Univ. Marit. Constanta 2010, 11, 216–218. [Google Scholar]
- Kadakal, M.; İşcan, İ. Exponential type convexity and some related inequalities. J. Inequal. Appl. 2020, 2020, 82. [Google Scholar] [CrossRef] [Scilit]
- Kadakal, M.; İşcan, İ.; Agarwal, P.; Jleli, M. Exponential trigonometric convex functions and Hermite-Hadamard type inequalities. Math. Slovaca 2021, 71, 43–56. [Google Scholar] [CrossRef] [Scilit]
- Awan, M.U.; Noor, M.A.; Noor, K.I. Hermite-Hadamard inequalitie for exponentially convex function. Appl. Math. Inf. Sci. 2018, 12, 405–409. [Google Scholar] [CrossRef] [Scilit]
- He, W.; Farid, G.; Mahreen, K.; Zahra, M.; Chen, N. On an integral and consequent fractional integral operators via generalized convexity. AIMS Math. 2020, 5, 7632–7648. [Google Scholar] [CrossRef] [Scilit]
- Rashid, S.; Ashraf, R.; Noor, M.A.; Noor, K.I.; Chu, Y.-M. New weighted generalizations for differentiable exponentially convex mapping with application. AIMS Math. 2020, 5, 3525–3546. [Google Scholar] [CrossRef] [Scilit]
- Qi, H.; Yussouf, M.; Mehmood, S.; Chu, Y.-M.; Farid, G. Fractional integral versions of Hermite-Hadamard type inequality for generalized exponentially convexity. AIMS Math. 2020, 5, 6030–6042. [Google Scholar] [CrossRef] [Scilit]
- Yıldız, Ç.; Bakan, E.; Dönmez, H. New general inequalities for exponential type convex function. Turk. J. Sci. 2023, 8, 11–18. [Google Scholar]
- Yıldız, Ç.; Yergöz, A. An investigation into inequalities obtained through the new lemma for exponential type convex functions. Filomat 2023, 37, 5149–5163. [Google Scholar]
- Zhou, S.S.; Rashid, S.; Noor, M.A.; Noor, K.I.; Safdar, F.; Chu, Y.M. New Hermite-Hadamard type inequalities for exponentially convex functions and applications. AIMS Math. 2020, 5, 6874–6901. [Google Scholar] [CrossRef] [Scilit]
- Sahoo, S.K.; Tariq, M.; Ahmad, H.; Nasir, J.; Aydi, H.; Mukheimer, A. New Ostrowski-Type Fractional Integral Inequalities via Generalized Exponential-Type Convex Functions and Applications. Symmetry 2021, 13, 1429. [Google Scholar] [CrossRef] [Scilit]
- İşcan, İ. New refinements for integral and sum forms of Hölder inequality. J. Inequal. Appl. 2019, 2019, 304. [Google Scholar] [CrossRef] [Scilit]
- Kadakal, M. Better results for Trigonometrically convex functions via Hölder-İşcan and Improved Power-Mean inequalities. Univ. J. Math. Appl. 2020, 3, 38–43. [Google Scholar] [CrossRef] [Scilit]
- Agarwal, P.; Kadakal, M.; İşcan, İ.; Chu, Y.-M. Better approaches for n-times differentiable convex functions. Mathematics 2020, 8, 950. [Google Scholar] [CrossRef] [Scilit]
- Özcan, S. Hermite–Hadamard type inequalities for m-convex and (α, m)-convex functions. J. Inequal. Appl. 2020, 2020, 175. [Google Scholar] [CrossRef] [Scilit]
- Özcan, S.; İşcan, İ. Some new Hermite–Hadamard type inequalities for s-convex functions and their applications. J. Inequal. Appl. 2019, 2019, 201. [Google Scholar] [CrossRef] [Scilit]
- Chen, S.-B.; Rashid, S.; Noor, M.A.; Hammouch, Z.; Chu, Y.-M. New fractional approaches for n-polynomial P-convexity with applications in special function theory. Adv. Diff. Equ. 2020, 2020, 543. [Google Scholar] [CrossRef] [Scilit]
- Lui, Z. A sharp generalized Ostrowski-Grüss Inequality. Tamsui Oxf. J. Math. Sci. 2008, 24, 175–184. [Google Scholar]
- Bayraktar, B.; Nápoles, V.J.E. New Generalized Integral Inequalities Via (h, m)-Convex Modified Functions. Izv. Inst. Mat. Inf. Udmurt. Gos. Univ. 2022, 60, 3–15. [Google Scholar] [CrossRef] [Scilit]
- Nápoles, V.J.E.; Bayraktar, B.; Butt, S. New integral inequalities of Hermite-Hadamard type in a generalized context. Punjab Univ. J. Math. 2021, 53, 765–777. [Google Scholar]
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content. |
© 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).