Abstract
In this work, we discover a new version of Hermite–Hadamard quantum integrals inequality via m-preinvex functions. Moreover, the authors present a quantum integrals identity and drive some new quantum integrals of Hermite–Hadamard-type inequalities involving generalized -preinvex functions.
1. Introduction
Quantum calculus or q-calculus is a methodology applicable to the typical study of calculus but it is mainly centered on the idea of derivation of q-analogous results excluding the use of limits. This concept was first introduced by Euler who started his study in the earlier years of the 18th century. It is the q-analogue of the ordinary derivative of a function, it is also known as Jackson or quantum derivative in some branches of mathematics, especially in combinatorics, see [1]. In recent years, the topic of q-calculus has attracted the attention of several scholars. That is why q-calculus is called a bridge between mathematics and physics. Having numerous applications in mathematics as well as in physics, q-calculus has emerged as an interesting and most fascinating field of research in recent years. Many researchers have written a number of papers on quantum integrals, for more details, see [2,3,4,5,6,7,8,9].
Inequality theory plays a key role in pure and applied sciences, and also has comprehensive applications in various areas of pure and applied mathematics.
A function is called convex on J if the inequality
holds for all and .
Motivated by the idea of convex function, Hermite and Hardamard [10] first introduced the following inequality that is called Hermite–Hadamard inequality:
Due to its geometrical interpretation and applications, the Hermite–Hadamard inequality is one of the finest inequalities among the inequalities of convex functions. This fundamental result of Hermite and Hadamard has attracted many mathematicians and consequently this inequality has been generalized and extended in different directions using novel and innovative ideas, see [11,12,13,14].
Next, Tariboon et al. [15,16] obtained some of the most important integral inequalities of analysis are extended to quantum calculus which is q-analogue of Hermite–Hadamard’s inequality on finite integral.
An important contribution to the subject was made by Alp et al. [17] who introduced corrected q-Hermite–Hadamard inequality, which can be written as:
Recently, Noor et al. [18] proposed some important results on quantum Hermite–Hadamard inequality for preinvex functions that can be written as follows:
A function be integrable and preinvex function with . If the bifunction satisfies the Condition C, then, we have
Proposition 1.
Let be a quantum differential mapping over (interior of ) with . If is continuous and integrable over . Then, the following identity holds:
Liu et al. [19] proposed the following results based on twice quantum integral identity and developed some trapezoid-type inequalities for convex function.
Proposition 2.
Let be a twice quantum differential mapping over (the interior of J) with being continuous and q-integrable over J, where . Then, the following identity holds:
Theorem 3.
Let be a twice quantum differential mapping over (the interior of J) with being continuous and q-integrable over J, where . If is convex on , then
Theorem 4.
Let be a twice quantum differential mapping over (the interior of J) with being continuous and q-integrable over I, where . If is convex on , where , , then
where
Theorem 5.
Let be a twice quantum differential mapping over (the interior of J) with being continuous and q-integrable over I, where . If is convex on for , then
2. Preliminaries
In this section, Suppose that is a nonempty bounded set in and denotes the interior of . The generic n-dimensional vector-space will be represented by and
Ben-Israel et al. [20] defined the concept of invex set as follows, which is a generalization of convex set:
Definition 1.
Let be an invex set with respect to , if
for all and .
Pini. R in [21] introduced the idea of invexity and generalized convexity
Definition 2.
Let be an invex set with respect to . Let be called a preinvex function if
holds for all and .
The following definitions for generalized -preinvex function, quantum derivative and integral of function h are stated as:
Author J. Y. Li [22] has introduced the concept of inequality for s-preinvex function
Definition 3.
Let be an invex set with respect to . A function is called s-preinvex function if
holds for all , and for some fixed .
Ting-Song Du et al. [23] first established the idea of m-invex set and generalized -preinvex functions as follows:
Definition 4.
Let be m-invex set with respect to the function for some fixed , if
holds for each and any .
Example 1.
Consider and
Clearly, Δ is an invex set with respect to υ but not a convex set.
Remark 1.
Definition 4 shows that the m-invex set degenerates to an invex set , if we take .
We introduce the new concept of generalized m-preinvex and -preinvex functions
Definition 5.
Let , h is said to be a generalized m-preinvex with respect to function for some fixed , if
holds for all and .
Definition 6.
Let , h is said to be a generalized -preinvex with respect to function for some fixed if
holds for all , .
Remark 2.
If we take in Definition 6, then the generalized -preinvex function could reduce to -convex function.
Example 2.
Let , and
Then, is a generalized -preinvex function with respect to and for some fixed .
Note: If we take in Example 1 and Example 2, then could reduce to .
In [24], Mohan et al. introduced the concept of well-known Condition C, rewritten as follows:
Definition 7.
Let be an invex set with respect to bifunction . Then, for any and ,
The idea of preinvex function is more generalized than convex function because every convex function is preinvex with respect to the property , but converse is not true.
We recall some previously known concepts on q-calculus which will be used in this paper. Tariboon et al. [16] proposed the concept of quantum derivative and integration over finite interval .
Definition 8.
Consider a continuous function , then, the quantum derivative of function h at with is written as
Since is a continuous function, we thus have .
If we take in (5), then , where is a familiar quantum derivative of defined by
Definition 9.
Consider a continuous function . We introduce the concept of 2nd-order quantum derivative on interval . In quantum calculus, the 2nd-order quantum derivative, denoted as , is defined as . Similarly, we define , which is called a higher-order quantum derivative on with
Example 3.
Define a function by with . Then, for we have
Definition 10.
Consider a continuous function . The quantum integral on with is stated as
for .
Example 4.
Define function by with Then, we have
Note that if we take in (6), then we obtain the concept of classical quantum integral as
for .
If , then the definite quantum integral on is expressed as
Lemma 1.
Let , then
Theorem 6.
Consider continuous functions , where . Then, for , with
In addition, we introduce the quantum analogues of , and the definition of the quantum Beta function, see [25].
Definition 11.
For any ,
is called the quantum analogues of σ.
In particular, for , we denote
Definition 12.
If n is an integer, the quantum analogue of is the polynomial
Definition 13.
For any ,
is called the quantum Beta function.
Note that
where is the quantum analogue of
3. Main Results
In this section, we introduce new quantum Hermite–Hadamard-type estimates within a class of generalized m-preinvex functions. Furthermore, we derive identity for twice q-differentiable function. By the help of this identity, we will prove our main results, these results are generalizations of the results proved by Liu et al. in [19]. Before that, for simplicity of the notations, we take , as the interval and as the interior of .
Theorem 7.
Let be an integrable and generalized m-preinvex function with , for some and . If satisfies condition C, we have
Proof.
Let h be a generalized m-preinvex function over and let condition C hold, then
applying quantum integral identity in Equation (7) over on , we get the following integral
Since h is generalized m-preinvex function, then . Therefore,
again applying quantum integral identity in (8) over on and using Definition 10, we have
Remark 3.
Under these conditions, the new inequalities recapture well-known previous inequalities.
- If , and , then Theorem 7 reduces to inequality (1).
- If and , then Theorem 7 reduces to inequality (3).
- If and , then Theorem 7 reduces to inequality (4).
Lemma 2.
Let be a twice quantum differentiable function on with being continuous and integrable on with and for some . Then, the following identity holds:
Proof.
Utilizing Definition 8 and Definition 9, we get
Applying this expression and Definition 10, we have
Multiplying both sides with , we complete the proof. □
Remark 4.
If we substitute and in Lemma 2, then it reduces to Proposition 2.
Theorem 8.
Let be a twice quantum differentiable function on with being continuous and q-integrable over with . If is a generalized -preinvex function on for some fixed , then the following inequalities hold:
where
Proof.
Using Lemma 2 and the generalized -preinvex of , we have
Now, we calculate the above quantum integral by applying Definition 10, then we get
Hence, the proof is complete. □
Corollary 1.
Let be a twice quantum differentiable function on with being continuous and integrable over . If is a generalized -preinvex function on for some fixed , then the following inequalities hold:
Proof.
We substitute in Theorem 8. Then, the quantum integral reduces to a classical integral and
□
Remark 5.
Substituting , and by using Definition 10 in Theorem 8, we obtain Theorem 3.
Theorem 9.
Let be a twice quantum differentiable function on with being continuous and q-integrable on with . If is a generalized -preinvex on for some fixed , where , , then
where
and
isq-analogue of.
Proof.
Using Lemma 2, application of Hölder inequality, and the generalized -preinvex of , we have
Applying Definition 10, we get
Hence, the proof is complete. □
Corollary 2.
Let be a twice quantum differentiable function on with being continuous and integrable over . If is a generalized -preinvex function on for some fixed , where , , then the following inequalities hold:
Proof.
We substitute in Theorem 9. Then, the quantum integral reduces to a classical integral and
Applying the properties of Beta function, that is,
we obtain
where and is a Gamma function:
□
Corollary 3.
If then
Under the above condition, Theorem 9 reduces to
Remark 6.
If we take , and by using Definition 10 in Theorem 9, then we obtain Theorem 4.
Theorem 10.
Let be a twice quantum differentiable function on with being continuous and q-integrable on with . If is generalized -preinvex on for some fixed , where , then
where
Proof.
Using Lemma 2, application of power mean inequality, and the generalized -preinvex of , we have
Applying Definition 10, we can easily calculate as
The proof is completed. □
Corollary 4.
Let be a twice quantum differentiable function on with being continuous and integrable over . If is generalized -preinvex function on for some fixed , where , then the following inequalities hold:
Proof.
We substitute in Theorem 10. Then, the quantum integral reduces to a classical integral and
□
Remark 7.
If we take , and by using Definition 10 in Theorem 10, then we obtain Theorem 5.
4. Conclusions
Quantum calculus has large applications in many mathematical areas such as number theory, special functions, quantum mechanics, and mathematical inequalities. In this paper, we first establish a new quantum integral identity and then develop some quantum estimates of Hermite–Hadamard-type inequalities for generalized -preinvex functions. These results in some special cases recapture the known results. We hope that our results may be helpful for further study.
Author Contributions
Y.D., H.K., and S.W. finished the proofs of the main results and the writing work. All authors contribut equally to writing of this paper.
Funding
This work was supported by the Teaching Reform project of Longyan University(Grant No.2017JZ02) and the Teaching Reform project of Fujian Provincial Education Department(Grant No. FBJG20180120).
Acknowledgments
The second author Humaira Kalsoom would like to express sincere thanks to the Chinese Government for providing full scholarship for PhD studies.
Conflicts of Interest
The authors declare that they have no competing interests.
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