1. Introduction
The convexity of a function has played a very important role as a tool in the development of inequalities. The relationship of this concept is always present in branches such as functional analysis [
1], harmonic analysis (specifically in interpolation theory) [
2] and control theory and optimization [
3]. This property is defined by Jensen in [
4,
5] as follows.
Definition 1. A function  is said to be convex on  if:holds for every  and   The famous Hermite–Hadamard inequality, which involves convex functions, appears in the literature regarding the study of inequalities. Its name was derived from the works of Hermite, Ch. [
6] and Hadamard J. [
7], and it was established as follows.
Theorem 1. Let  be a convex function on I and  with  Then the following inequality holds: Inequality (1) is also known as trapezium inequality.  The trapezium-type inequality has remained a subject of great interest due to its broad application in the field of mathematical analysis. For other recent results which generalize, improve and extend inequality (
1) through various classes of convex functions, interested readers may consult [
8,
9,
10,
11,
12,
13].
Quantum calculus, also known as calculus with no limits, was begun by Euler in the eighteenth century (1707–1783). In 1910, Jackson F.H. [
14] began a symmetric study of q-calculus and introduced q-definite integrals. He was also the first to develop q-calculus in a systematic fashion. Some branches of mathematics and physics, such as number theory, orthogonal polynomials, combinatorics, basic hypergeometric functions, quantum theory, mechanics and the theory of relativity, have been enriched by the research work of various authors such as Ernst T. [
15], Gauchman H. [
16] and Kac V. [
17].
Motivated by the growing body of work on the development of the concept of convexity, its relationships with integral inequalities and its connection with quantum analysis, as is addressed in the work mentioned above, in this work we seek to establish certain quantum estimates of trapezium-type inequalities for generalized -convex functions.
  2. Preliminaries
Let K be a non-empty closed set in  and  a continuous function.
In [
10], Noor M.A. introduced a new class of non-convex functions, the so-called 
-convex, as follows:
Definition 2. The function  on the ϕ-convex set K is said to be ϕ-convex, if:  The function f is said to be -concave if  is -convex. Note that every convex function is -convex but in general the converse does not hold.
In [
18], Raina R.K. introduced a class of functions defined by:
 where 
 and:
 is a bounded sequence of positive real numbers. Note that, if we take in (
2) 
 and:
 where 
 and 
 are parameters which can take arbitrary real or complex values (provided that 
 and the symbol 
 denotes the quantity:
 and restrict its domain to 
 (with 
), then we have the classical hypergeometric function, which is:
In addition, if 
 with 
 and restricting its domain to 
 in Equation (
2), then we have the classical Mittag-Leffler function:
Finally, let us recall the new class of set and new class of functions involving Raina’s function introduced by Vivas-Cortez et al. in [
13], the so-called generalized 
-convex set as well as the generalized 
-convex function.
Definition 3. Let  and  be a bounded sequence of positive real numbers. A non-empty set K is said to be a generalized ϕ-convex set, if:where  is Raina’s function.  Definition 4. Let  and  be a bounded sequence of positive real numbers. If a function  satisfies the following inequality:for all  and  then f is called generalized ϕ-convex.  Remark 1. Taking  in Definition 4, we then obtain Definition 1. Moreover, under suitable choices of  we get Definition 2.
 Recently, several authors have utilized quantum calculus as a strong tool in establishing new extensions of trapezium-type and other inequalities, see [
17,
19,
20,
21,
22,
23,
24] and the references therein.
We now recall some concepts from quantum calculus. Let  be an interval and  be a constant.
Definition 5 ([
23]). 
Let  be a continuous function and  Then q-derivative of f on I at x is defined as:We say that f is q-differentiable on I provided  exists for all  Note that if  in Equation (5), then  where  is the well-known q-derivative of the function  defined by:  Definition 6 ([
23]). 
Let  be a continuous function. Then the second-order q-derivative of f on  which is denoted as  provided  is q-differentiable on I with  Definition 7 ([
23]). 
Let  be a continuous function. Then the q-integral on I is defined by: for  Note that if  then we have the classical q-integral, which is defined by: for  Theorem 2 ([
23]). 
Assume that  are continuous functions,  Then, for  we have: Definition 8 ([
17]). 
For any real number  is called the q-analogue of . If  we denote: Definition 9 ([
17]). 
If  the q-analogue of  is the polynomial: Definition 10 ([
17]). 
For any  is called the q-Beta function. Note that: where  is the q-analogue of  Finally, from [
24], four simple lemmas will be used in this paper.
Lemma 1. Let  then we have:  Lemma 2. Let  then we have:  Lemma 3. Let  where  is a constant, then we have:  Lemma 4. Let  where  is a constant, then we have:  Liu et al. in [
20] established the following 
q-integral identity.
Lemma 5. Let  be a twice q-differentiable function on  with  being continuous and integrable on  where  Then the following identity holds:  Motivated by the aforementioned literature, this paper is organized as follows: In 
Section 3, a quantum trapezium-type inequality using a new class of functions, the so-called generalized 
-convex, will be represented. A quantum trapezium-type inequality for the product of two generalized 
-convex functions will also be provided. In 
Section 4, an identity for a twice 
q-differentiable functions involving Raina’s function will be established. Applying these identities, we develop some quantum estimate inequalities for the above class of functions. Various special cases will be obtained. In 
Section 5, a brief conclusion is given.
  3. Quantum Trapezium-Type Inequalities
Throughout this paper the following notations are used:
 where 
 and 
 are bounded sequence of positive real numbers. Moreover, for convenience we denote 
 for 
 where 
In this section, we first establish quantum estimates for trapezium-type inequalities via generalized -convexity.
Theorem 3. Let  be a generalized ϕ-convex function on  (the interior of O) such that  Then the following double inequality holds:  Proof.  Let 
 and 
 Then:
        
Since 
f is a generalized 
-convex function, we have:
        
 and:
        
Taking the 
q-integral of both sides in Equation (
7) with respect to ı on 
 we get:
        
Changing the variables of integration in Equation (
8), we obtain the left-side inequality of Equation (
6). To prove the right-side inequality of Equation (
6), from generalized 
-convexity of 
 we have:
        
Changing the variables of integration, we obtain the right-side inequality of Equation (
6). The proof of Theorem 3 is completed. □
 Corollary 1. In Theorem 3, taking  we get the following new double inequality:  Remark 2. In Corollary 1, taking  we recapture Theorem 1.
 We are now in a position to derive a new quantum trapezium-type inequality for the product of two generalized -convex functions.
Theorem 4. Let  be two generalized ϕ-convex functions on  (the interior of O) such that  Then the following double inequality holds:where:and:  Proof.  Let 
 and 
 Then:
        
 and:
        
Since 
f and 
g are generalized 
-convex functions, we have:
        
 and:
        
Multiplying the above inequalities, we have:
        
Taking the 
q-integral of both sides in Equation (
12) with respect to ı on 
 and changing the variables of integration, we get:
        
By using Lemmas 1–4, the left-side inequality of Equation (11) is proved. To prove the right-side inequality of Equation (11), from the generalized 
-convexity of 
f and 
 we have:
        
The right-side inequality of Equation (11) is thus proved. The proof of Theorem 4 is completed. □
 Corollary 2. In Theorem 4, taking  we get the following new double inequality:  Corollary 3. In Corollary 2, taking  we get:  Corollary 4. In Theorem 4, taking  we get:    4. Other Quantum Inequalities
In this section, we first derive a new quantum integral identity for twice q-differentiable functions involving Raina’s function.
Lemma 6. Let  be a twice q-differentiable function on  with  being continuous and integrable on  Then the following identity holds:where:  Proof.  Using Definitions 5–7, we have:
        
Multiplying both sides of the above equality: by  we get the desired result. The proof of Lemma 6 is completed. □
 Remark 3. Taking  in Lemma 6, we obtain the following new identity:where:  Remark 4. Taking  in Lemma 6, we get Lemma 5.
 Now, applying Lemma 6, we establish some quantum estimate inequalities for the generalized -convex function.
Theorem 5. Let  be a twice q-differentiable function on  with  being continuous and integrable on  If  is generalized ϕ-convex on  then the following inequality holds:where:  Proof.  Using Lemmas 1–4 and Lemma 6 and the fact that 
 is a generalized 
-convex function, we have:
        
The proof of Theorem 5 is completed. □
 Corollary 5. Taking  in Theorem 5, we get:  Corollary 6. Taking  in Theorem 5, we get:  Theorem 6. Let  be a twice q-differentiable function on  with  being continuous and integrable on  If  is a generalized ϕ-convex on  for  and  then the following inequality holds:where:  Proof.  Using Lemmas 1–4 and Lemma 6, Hölder’s inequality and the fact that 
 is a generalized 
-convex function, we have:
        
The proof of Theorem 6 is completed. □
 Corollary 7. Taking  in Theorem 6, we get:  Corollary 8. Taking  in Theorem 6, we get:  Theorem 7. Let  be a twice q-differentiable function on  with  being continuous and integrable on  If  is generalized ϕ-convex on  then for  the following inequality holds:where  is defined from Theorem 4 and  is defined from Theorem 5.  Proof.  Using Lemmas 1–4 and Lemma 6, the well-known power mean inequality and the fact that 
 is a generalized 
-convex function, we have:
        
The proof of Theorem 7 is completed. □
 Corollary 9. Taking  in Theorem 7, we get Theorem 5.
 Corollary 10. Taking  in Theorem 7, we get:  Corollary 11. Taking  in Theorem 7, we get:  Theorem 8. Let  be a twice q-differentiable function on  with  being continuous and integrable on  If  is generalized ϕ-convex on  for  and  then the following inequality holds:where:and  is defined from Theorem 4.  Proof.  Using Lemmas 1–4 and Lemma 6, Hölder’s inequality and the fact that 
 is a generalized 
-convex function, we have:
        
The proof of Theorem 8 is completed. □
 Corollary 12. Taking  in Theorem 8, we get:  Corollary 13. Taking  in Theorem 8, we get:  Theorem 9. Let  be a twice q-differentiable function on  with  being continuous and integrable on  If  is generalized ϕ-convex on  then for  the following inequality holds:where:and  is the q-analogue of   Proof.  Using Lemmas 1–4 and Lemma 6, the well-known power mean inequality and the fact that 
 is a generalized 
-convex function, we have:
        
The proof of Theorem 9 is completed. □
 Corollary 14. Taking  in Theorem 9, we get:where:  Corollary 15. Taking  in Theorem 9, we get:  Theorem 10. Let  be a twice q-differentiable function on  with  being continuous and integrable on  If  is generalized ϕ-convex on  for  and  then the following inequality holds:where  is defined from Theorem 4 and  is a q-Beta function.  Proof.  Using Lemmas 1–4 and Lemma 6, Hölder’s inequality and the fact that 
 is a generalized 
-convex function, we have:
        
The proof of Theorem 10 is completed. □
 Corollary 16. Taking  in Theorem 10, we get:  Corollary 17. Taking  in Theorem 10, we get:  Theorem 11. Let  be a twice q-differentiable function on  with  being continuous and integrable on  If  is generalized ϕ-convex on  then for  the following inequality holds:where  is defined from Theorem 8, for   Proof.  Using Lemmas 1–4 and Lemma 6, the well-known power mean inequality and the fact that 
 is a generalized 
-convex function, we have:
        
The proof of Theorem 11 is completed. □
 Corollary 18. Taking  in Theorem 11, we get:  Corollary 19. Taking  in Theorem 11, we get:  Theorem 12. Let  be a twice q-differentiable function on  with  being continuous and integrable on  If  is generalized ϕ-convex on  for  and  then the following inequality holds:where  is the q-analogue of and  is defined from Theorem 8, for   Proof.  Using Lemmas 1–4 and Lemma 6, Hölder’s inequality and the fact that 
 is a generalized 
-convex function, we have:
        
The proof of Theorem 12 is completed. □
 Corollary 20. Taking  in Theorem 12, we get:  Corollary 21. Taking  in Theorem 12, we get:  Theorem 13. Let  be a twice q-differentiable function on  with  being continuous and integrable on  If  is generalized ϕ-convex on  for  and  then the following inequality holds:where  is the q-analogue of r and  is defined from Theorem 12, for   Proof.  Using Lemmas 1–4 and Lemma 6, Hölder’s inequality and the fact that 
 is a generalized 
-convex function, we have:
        
The proof of Theorem 13 is completed. □
 Corollary 22. Taking  in Theorem 13, we get:  Corollary 23. Taking  in Theorem 13, we get:  Theorem 14. Let  be a twice q-differentiable function on  with  being continuous and integrable on  If  is generalized ϕ-convex on  then for  the following inequality holds:where:  Proof.  Using Lemmas 1–4 and Lemma 6, the well-known power mean inequality and the fact that 
 is a generalized 
-convex function, we have:
        
The proof of Theorem 14 is completed. □
 Corollary 24. Taking  in Theorem 14, we get:  Remark 5. For different choices of  where  are bounded sequence of positive real numbers in Raina’s function, we can arrive at new fascinating inequalities. Moreover, our results can be applied to derive some inequalities using special means. For example, from Corollary 5 taking , and recalling the well known means:
- 1. 
- 2. 
- Generalized Logarithmic:we have the following inequality: 
The details are left to the interested reader.
   5. Conclusions
Since quantum calculus is broadly applicable in many mathematical areas, this new class of functions, the so-called generalized -convex, can be applied to obtain various results in convex analyses, special functions, quantum mechanics, related optimization theories and mathematical inequalities and it may stimulate further research in different areas of pure and applied sciences.