Abstract
In this paper, we derive some new quantum estimates of generalized Hermite–Hadamard–Jensen–Mercer type of inequalities, essentially using q-differentiable convex functions. With the help of numerical examples, we check the validity of the results. We also discuss some special cases which show that our results are quite unifying. To show the efficiency of our main results, we offer some interesting applications to special means.
Keywords:
convex function; quantum calculus; Jensen–Mercer inequalities; differentiable function; means MSC:
05A30; 26A51; 26D10; 26D15
1. Introduction and Preliminaries
A set is said to be convex if
for all and .
A function is said to be convex if
for all and .
The theory of convexity has played a vital role in developing inequality theory. Many inequalities are direct consequences of applying the convexity property of the functions. One of the most studied results in this regard is Hermite–Hadamard’s inequality. This inequality provides us with necessary and sufficient conditions for a function to be convex. For details, see [1]. It reads as:
If be a convex function, then
Another significant result of convexity property of the functions is Jensen’s inequality, which reads as:
Let be non-negative weights such that . If is a convex function, then
where and , . For more details, see [2].
The following inequality is known as Jensen-Mercer’s inequality.
Let be a convex function; then
for each and , with . For more details, see [3].
Pavić [4] obtained a generalized version of Jensen–Mercer’s inequality in the following way:
Assume that is a convex function, where are n-points. Let be coefficients such that . Then
The classical concepts of convexity also have a close relation with the concept of symmetry. Several significant properties of symmetric convex sets can be found in the literature. A beneficial point of view of the relation between convexity and symmetry is that we work on one and apply it to the other. For some more useful information, see [5,6].
Quantum calculus (often known as calculus without limits) is the branch of mathematics in which we obtain q-analogues of mathematical objects, which can be recaptured by taking . In recent years, the classical concepts of quantum calculus have been refined and generalized in different directions using novel and innovative ideas. For instance, Tariboon and Ntouyas [7] defined the q-derivative as:
Definition 1
([7]). Assume is a continuous function and suppose ; then
for and .
We say that is q-differentiable on J provided exists for all . Note that if in (1), then , where is the well-known classical q-derivative of the function defined by
Additionally, here and further we use the following notation for the q-number:
Jackson gave the q-Jackson integral from 0 to for as follows:
provided the sum converges absolutely.
Jackson also gave the q-Jackson integral in a generic interval as:
We now give the definition of a -definite integral.
Definition 2
([7]). Let be a continuous function. Then, the -definite integral on is defined as:
where .
The following is the quantum analogue of Hermite–Hadamard’s inequality:
Theorem 1
([8]). Let be a convex function; then, for , we have
For some recent studies regarding quantum analogues of integral inequalities involving convexity and its generalizations, see [9,10,11].
We now give the definition of a -definite integral.
Definition 3
([12]). Let be a continuous function. Then, the -definite integral on is defined as:
Using Definition 3, one can have the following quantum version of Hermite–Hadamard’s inequality.
Theorem 2
([12]). Let be a convex function; then, for , we have
In the literature, there are several papers devoted to finding the bound for the left sides and right sides of Inequalities (3) and (4). These types of inequalities are called quantum trapezoid- and midpoint-type inequalities, respectively. By using -integrals, the authors established some quantum trapezoid- and quantum midpoint-type inequalities in [8,9], respectively. On the other hand, in [13], Budak proved corresponding quantum trapezoid and quantum midpoint type inequalities for -integrals. Zhao et al. presented some quantum inequalities for -convex functions in [14]. Du et al. derived some parameterized inequalities which generalize quantum midpoint- and quantum trapezoid-type inequalities for -integrals in [15]. Moreover, in [16], Zhao et al proved some parameterized quantum inequalities involving both the -integral and -integral. For similar quantum inequalities, one can refer to the papers [17,18,19,20].
The main objective of this paper is to derive some new quantum estimates of generalized Hermite–Hadamard–Jensen–Mercer type inequalities essentially using q-differentiable convex functions. We discuss some special cases which show that our results are quite unifying. Lastly, we offer some applications of the obtained results to means that establish our results’ efficiency. We hope that the ideas and techniques of this paper will inspire interested readers working in this field.
2. Main Results
In this section, we discuss our main results.
Theorem 3.
Let be a convex function; then
for all with and .
Proof.
From Definition 2 and Theorem 1, we have
Additionally, by the Jensen–Mercer inequality, we obtain
This completes the proof. □
Remark 1.
If we take and take limit in Theorem 3, then (5) reduces to the following inequality:
Theorem 4.
Let be a convex function; then,
for all with and .
Proof.
From Definition 3 and Theorem 2, we have
which gives the proof of first inequality in (7). Additionally, by the Jensen-Mercer inequality, we obtain
This completes the proof. □
Remark 2.
If we take and take limit in Theorem 4, then Inequality (7) reduces to the following inequality:
We provide some examples of our main theorems in this section.
Example 1.
Consider the convex function defined by with and . Then, we have
and
Example 2.
Consider the convex function defined by with and . Then, we have
and
We now derive a new q-integral identity. This result will serve as an auxiliary result for our coming results.
Lemma 1.
Let be a continuous function and . If is an integrable function on , then
Proof.
Using Definitions 1 and 2, we have
The completes the proof. □
Remark 3.
If we take and in Lemma 1, then we have
Theorem 5.
Let be a continuous function. If is convex and integrable on , then
Proof.
Using Lemma 1, the Jensen–Mercer inequality and the convexity of on , we have
The proof is complete. □
Remark 4.
If we take and in Theorem 5, then the inequality (17) reduces to the integral inequality:
Theorem 6.
Let be a continuous function. If is convex and integrable on , and , then
Proof.
From Lemma 1, we have
Using the power-mean inequality,
Now using the Jensen–Mercer inequality and convexity of , it follows that
This completes the proof. □
Remark 5.
If we take and in Theorem 6, then the inequality (19) reduces to the integral inequality:
Theorem 7.
Let be a continuous function. If is convex and integrable on , where and , then
where
Proof.
From Lemma 1, we have
Now using the Jensen–Mercer inequality, Hölder’s inequality and the convexity of , it follows that
It is easy to see that
This completes the proof. □
Remark 6.
If we take and in Theorem 7, then the inequality (23) reduces to the integral inequality:
Example 3.
Consider the convex function , with and . Then, we have
and
3. Applications
In this section, we discuss some applications to means. For arbitrary real numbers, we consider the following means:
- The arithmetic mean:
- The generalized -mean:where and .
Proposition 1.
Let and . If ; then
Proof.
The proof is obvious from Theorem 5 applied for . □
Proposition 2.
Let and . If ; then
Proof.
The proof is obvious from Theorem 6 applied for . □
Proposition 3.
Let and . If ; then
Proof.
The proof is obvious from Theorem 7 applied for . □
4. Conclusions
We have derived some new quantum estimates of the generalized Hermite–Hadamard–Jensen–Mercer type of inequalities by using the class of q-differentiable convex functions. We have discussed several special cases which can be deduced from the main results of the paper. This shows that the results obtained in this paper are unifying and represent a significant q-generalizations of the classical results. In order to elaborate on the efficiency of the main results, we have also presented some applications to means. We would like to mention here that the results of this paper can be extended by using post-quantum calculus and other convexity classes. This will be an interesting problem for future research.
Author Contributions
All authors contributed equally to this article. All authors have read and agreed to the published version of the manuscript.
Funding
This research was funded by King Saud University grant number RSP-2021/158.
Institutional Review Board Statement
Not applicable.
Informed Consent Statement
Not applicable.
Data Availability Statement
Not applicable.
Acknowledgments
The authors are thankful to the editor and the anonymous reviewers for their valuable comments and suggestions. This research is supported by Project number (RSP-2021/158), King Saud University, Riyadh, Saudi Arabia.
Conflicts of Interest
The authors declare that they have no competing interest.
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