Abstract

In this article, we present new integral inequalities for refined -convex functions using unified integral operators (12) and (13). The established results provide the refinements of several well-known integral and fractional integral inequalities.

1. Introduction

Convex functions are important in diverse fields of mathematics, statistics, engineering, and optimization. Especially in the formation of inequalities, they play a very vital role. In the subject of mathematical analysis, inequalities provide a significant contribution in developing classical concepts and notions. For example, inequalities well known as Cauchy–Schwarz inequality, Chebyshev inequality, Minkowski inequality, Hadamard inequality, and Jensen inequality are utilized frequently in pure and applied mathematics. It is always a challenge to extend, generalize, and refine such inequalities by considering new classes of functions. In this era, researchers are working on classical inequalities concerning fractional integral and derivative operators. It can be observed that the Hadamard inequality is studied more for many kinds of fractional integral and derivative operators than any other classical inequality, see [17] for more details.

The aim of this paper is to study the refinements of Hadamard and other integral inequalities recently studied in [811]. The consequences of these inequalities also provide refinements of fractional integral inequalities connected with the integral inequalities studied in the recent past.

The article is organized as follows. In Section 2, we suggest some preliminaries. In Section 3, the bounds of unified integral operators are given using refined -convex functions. These are the refinements of bounds already obtained in the literature. In Section 4, some applications of the main results are given in the form of fractional integral inequalities and their refinements.

2. Preliminaries

In this section, we give definitions of different kinds of convex functions and integral operators which will be useful in formulating the results of this paper. Throughout the paper, all the functions are assumed to be real-valued functions until specified.

Definition 1. (see [12]). A function is called convex ifholds for all and .

Definition 2. (see [1]). A function is called -convex if for each , we havewhere and .

Definition 3. (see [13]). A function is called -convex if for each , we havewhere and .

Definition 4. (see [4]). Let is a function with and . A function is said to be -convex, if and for each , we havewhere and .

Definition 5 (see [4]). Let is a function with and . A function is said to be -convex, if and for each , we havewhere and .

Definition 6. (see [14]). Let be a function with and . A function is called refined -convex function, if and for each , we havewhere and .
Inequality (6) gives refinements of several types of convexities when , see [14].
The need for integral operators in the study of fractional derivatives is of immense importance. In the recent era, integral operators are being used extensively for producing new results in the literature. For references, see [2, 46]. Next, we give some fundamental integral operators which are used in this paper.

Definition 7. (see [15]). Let and be positive and increasing function having a continuous derivative on . The left and right fractional integrals of with respect to on of order are given bywhere is the gamma function and .

Definition 8. (see [16]). Let and be positive and increasing function having a continuous derivative on . The left and right -fractional integrals of with respect to on of order are given bywhere is the -gamma function and .

Definition 9 (see [17]). Let and , also let with , and , then the generalized fractional integral operators and are defined bywhere is the extended generalized Mittag–Leffler function defined as

Definition 10 (see [16]). Let be real-valued functions defined over with , where is positive and integrable and is differentiable and strictly increasing. Also, let be an increasing function on and , and . Then, for , the left and right integral operators are defined aswhereMittag–Leffler functions give several fractional integrals by assigning particular choice to the parameters involved in it, see Remarks 6 and 7 in [16].

3. Main Results

Throughout the paper, we use the following notation:

Theorem 1. Let be a positive, refined -convex and integrable function defined over . Also, let be an increasing function defined on and be strictly increasing and differentiable function on . Then, for , and , the following result holds:

Proof. For the functions and , the following inequality holds:Using refined -convexity of , one can haveFrom (17) and (18), we have the following integral inequality:Using (12) of Definition 10 on the left side of inequality (19) and making change of the variable by setting on the right-hand side of the above inequality, we obtainThus, we obtainAlso, for and , we can writeandFrom (22) and (23), we have the following integral inequality:Using (13) of Definition 10 on the left-hand side and making change of the variable by setting on the right-hand side of the above inequality, we obtainTherefore,Combining (21) and (26), the required inequality (16) is obtained. Hence, the proof is completed.
Next, we give the refinement of Theorem 1.

Theorem 2. Under the assumptions of Theorem 1, if , then the following result holds:

Proof. From (18) and (23), one can see that, for ,Hence, by following the proof of Theorem 1, one can obtain (27). Hence, the proof is completed.

Corollary 1. Under the assumptions of Theorem 1, (16) gives the following result:

Now, we give the refinement of Theorem 5 in [9] in the following corollary.

Corollary 2. The following inequality for refined -convex function holds:

Proof. Using and in (27), we obtain inequality (30).

Remark 1. (i)For , with , inequality (16) coincides with Theorem 10 in [18](ii)For along with the conditions of (i), inequality (29) coincides with Theorem 6 in [18](iii)For as identity function along with the conditions of (i), inequality (29) coincides with Theorem 5 in [14](iv)For as identity function and along with the conditions of (i), inequality (29) coincides with Theorem 1 in [14](v)For and , inequality (16) coincides with Theorem 4 in [19](vi)For and , inequality (29) coincides with Corollary 1 in [19](vii)For and along with the conditions of (i), inequality (29) coincides with Theorem 3.1 in [20](viii)For along with the conditions of (iv), inequality (29) coincides with Theorem 2 in [14](ix)For and along with the conditions of (iii), inequality (29) coincides with Corollary 8 in [14](x)For and along with the conditions of (iii), inequality (29) coincides with Corollary 14 in [14](xi)For and along with the conditions of (iii), inequality (29) coincides with Corollary 15 in [14](xii)For and along with the conditions of (iii), inequality (29) coincides with Corollary 16 in [14](xiii)For and along with the conditions of (iv), inequality (29) coincides with Corollary 1 in [14](xiv)For and along with the conditions of (iv), inequality (29) coincides with Corollary 2 in [14](xv)For and along with the conditions of (iv), inequality (29) coincides with Corollary 4 in [14](xvi)For and along with the conditions of (iv), inequality (29) coincides with Corollary 5 in [14]By using and making different choices of functions and and the parameters in (16), one can get the refinements of many well-known inequalities for different classes of convex functions which are mentioned in Remark 3 in [9].
Next, we give a lemma which we will use in the proof of upcoming Theorem 3.

Lemma 1. Let be a refined -convex function. If , and , then the following inequality holds:

Proof. Since is refined -convex, then following inequality holds:Using in the above inequality, we obtain (31). This completes the proof.

Remark 2. (i)For and , (31) coincides with Lemma 1 in [19](ii)For , (31) gives refinement of Lemma 1 in [9]

Theorem 3. Under the assumptions of Theorem 1, the following result holds for :

Proof. For the kernel defined in (14) and function , the following inequality holds:Using refined -convexity of , we haveFrom (34) and (35), we have the following integral inequality:Using (13) of Definition 10 on the right-hand side and making change of the variable by setting on the right-hand side of the above inequality, we obtainThe following inequality also holds true for :From (35) and (38), the following integral inequality is obtained:Using (12) of Definition 10 on the left-hand side and making change of the variable on the right-hand side of the above inequality, we obtainNow, using Lemma 1, we can writewhich by using (13) of Definition 10 gives the following integral inequality:Again, using Lemma 1, we can writewhich by using (12) of Definition 10 gives the following fractional integral inequality:Inequality (33) will be obtained by using (37), (40), (42), and (44).
The following theorem is the refinement of Theorem 3.

Theorem 4. Under the assumptions of Theorem 3, if , then the following refinement holds:

Proof. From (35), one can see that, for ,Hence, by following the proof of Theorem 3, one can obtain (45). This completes the proof.

Corollary 3. Under the assumptions of Theorem 3, (33) gives the following result:Now, we give the refinement of Theorem 6 in [9] in the following corollary.

Corollary 4. The following inequality for refined -convex function holds:

Proof. For and in (45), one can obtain (48).

Remark 3. (i)For and , inequality (33) coincides with Theorem 5 in [19](ii)For and , inequality (47) coincides with Corollary 2 in [19]By using and making different choices of functions and and the parameters in (33), one can get the refinements of many well-known inequalities for different classes of convex functions which are mentioned in Remark 5 of [9].

Theorem 5. Let be differentiable functions such that is refined -convex and be strictly increasing over and differentiable over . Also, be an increasing function on and , , and . Then, for , we havewhere

Proof. Using refined -convexity of over impliesAbsolute value property implies the following relation:From (17) and the second inequality of (52), we have the following inequality:which leads to the following fractional integral inequality:Also, inequality (17) and the first inequality of (52) give the following fractional integral inequality:Again, using refined -convexity of over , we can writeandFrom (22) and the second inequality of (57), the following fractional integral inequality is obtained:and (22) and the first inequality of (57) give the following fractional integral inequality:Inequality (49) will be obtained by using (54), (55), (58), and (59). Hence, the proof is completed.
Next, we give refinement of Theorem 5 in the following theorem.

Theorem 6. Under the assumptions of Theorem 5, if , then the following refinement holds:

Proof. From (51), one can see that, for ,Hence, by following the proof of Theorem 5, one can obtain (60). This completes the proof.

Corollary 5. Under the assumptions of Theorem 5, (49) gives the following result:

The following corollary presents the refinement of Theorem 7 in [9].

Corollary 6. The following inequality for refined -convex function holds:

Proof. For and in (60), we obtain (63).

Remark 4. (i)For and , inequality (49) coincides with Theorem 6 in [19](ii)For and , inequality (62) coincides with Corollary 3 in [19]By using and making different choices of functions and and the parameters in (49), one can get the refinements of many well-known inequalities for different classes of convex functions which are mentioned in Remark 6 of [9].

4. Inequalities for Fractional Integral Operators

In this section, we present the bounds of some of the fractional integral operators which will be deduced from the results of Section 3.

Proposition 1. Under the assumptions of Theorem 1, the following result holds:

Proof. For , and in the proof of Theorem 1, we obtain (64).

Proposition 2. Under the assumptions of Theorem 1, the following inequality holds:

Proof. Using as identity function with in the proof of Theorem 1, we obtain the required result.

Corollary 7. For with and , (12) and (13) reduce to the fractional integral operators (8) and (9), which satisfy the following upper bound:

Remark 5. For , (66) gives refinement of Corollary 8 in [9].

Corollary 8. Using and as identity function for along with , (12) and (13) give fractional integral and defined in [15], which satisfy the following upper bound:

Corollary 9. Using and as identity function along with , (12) and (13) reduce to the fractional integral operators and given in [21], which satisfy the following upper bound:

Remark 6. For , (68) gives refinement of Corollary 10 in [9].

Corollary 10. For in Corollary 9, the following upper bound for Riemann–Liouville fractional integral is satisfied:

Remark 7. For , (69) gives refinement of Corollary 11 in [9].
Similar bounds can be obtained for Theorems 3 and 5, which we leave for the reader.

5. Conclusions

This article is about the bounds of unified integral operators via refined -convexity. The obtained results are the refinements of some already published results. Moreover, some deducible fractional integral operators and their related bounds are also given.

Data Availability

No data were used to support this study.

Conflicts of Interest

The authors declare that they have no conflicts of interest.