1. Introduction
During the last century, the notion of convexity and its generalizations have emerged as an interesting field of pure and applied mathematics. This theory plays a crucial and consequential role in applied mathematics, especially in control theory, optimization theory, nonlinear programming and functional analysis. In economics, this theory plays a fundamental role in equilibrium and duality theory. The concept of a convex function is expressed as follows:
A real valued function
(set of real numbers) is said to be convex iff the following inequality is satisfied (see [
1])
for all
Let
be a convex function with
and
Then the H–H inequality is expressed as follows: (see [
2]):
The study of inequality theory gives a huge system for managing symmetrical aspects in real-life circumstances. The well-known features of integral inequalities have a strong chance to manage consistent issues with high capability. This manuscript contributes to a captivating association of integral calculus, special functions and convex functions. The authors foster a novel methodology for examining another class of convex function which is known as an m–polynomial p–harmonic s–type convex function.
Several mathematicians have put their insight into this field, presenting new versions of different types of inequalities with convex sets and convex functions. It is seen that the modern and amazing view point on convexity always provides ideas and fruitful applications in every field and branch of pure and applied mathematics. Among all the inequalities, most extensively used are H–H (Hermite–Hadamard)-type and Ostrowski-type inequalities. These inequalities involving convex functions play a consequential and fundamental role in mathematical analysis as well as in other areas of pure and applied mathematics. Thus, convex analysis and inequalities have been referred to as an absorbing field for the mathematicians due their wide applications in different branches of sciences. The reader can refer to [
3,
4,
5,
6,
7,
8]. Recently, Toplu et al. [
9], investigated a generalized form of convexity called
n–polynomial convex function and obtained a corresponding H–H inequality.
Harmonic mean is used to define the harmonic convex set. In 2003, the concept of harmonic set was introduced by Shi [
10] and consequently, Anderson et al. [
11] and Noor et al. [
12] introduced harmonic and
p–harmonic convex functions, respectively. Noor [
13] generalized the class of
n–polynomial convex function, called an
n–polynomial harmonic convex function. Recently, İşcan et al. [
14] introduced
s–type and
n–polynomial
s–type convex functions.
The focal length
f is one-half of the harmonic mean of the distances of the image
v and object
u from the lens. The thin lens equation is presented as
As far as the importance of harmonic mean is concerned, in [
15], the authors have examined its significant role in Asian investment opportunities. Curiously, harmonic means have been applied in electric circuits to determine the overall resistance of electrical resistors connected in parallel. That, the absolute obstruction/resistance of several resistors is only half of the harmonic mean of all of the resistors. For instance, in the event that
and
are the resistances offered by two resistors, then the final resistance is given by the equation:
In 1938, A. Ostrowski presented an inequality, the Ostrowski inequality, to the world of mathematics. This inequality has an extraordinary range of applications in likelihood, mathematical coordination, and numerical investigation. In the present scenario, nobody can disregard and reject its significance and meaning.
As of late, various extensions and generalizations of Ostrowski’s inequality utilizing various strategies are composed by many scientists. For instance, Alomari et al. [
16] employed
s–convex function to get Ostrowski-type disparities. Consequently, Ardic et al. [
17] used GA–convex and GG–convex functions. Budak and Sarikaya [
18] likewise obtained some weighted Ostrowski-type inequalities for differentiable convex functions. Iscan [
19] acquired some Ostrowski type inequalities utilizing the class of harmonically
s–convex functions. Mohsin et al. [
20] got new variants of Ostrowski-type inequalities utilizing harmonically
h–convex functions.
The motivation of this work reverberates in all aspects of this article. This paper has numerous reasons. Our first aim is to present the idea of the m-polynomial p-harmonic s–type convex functions. Considering two identities, we determined a few H–H type inequalities involving notable integral inequalities such as Hölder’s inequality and power-mean inequality. The second fundamental goal is to gather the results from our discoveries for special means such as arithmetic mean, geometric mean and harmonic mean.
The paper is coordinated as follows. In
Section 2, we review some essential and principal definitions related to the new convex function. In
Section 3, we give the definition of
m-polynomial
p-harmonic
s–type convex functions and explain their algebraic properties and formulate some examples. In
Section 4, a H–H-type inequality employing the newly introduced harmonic convexity is presented. In
Section 5, we build up the H–H type inequalities for differentiable functions as refinements. In
Section 6, we present one new identity and, employing this, some Ostrowski-type inequalities for the aforementioned strategy are established. In
Section 7, we present the applications of our outcomes to special means.
Before we start, we need the following necessary known definitions and literature references. Throughout the paper, for brevity we have used “poly” for polynomial and H–H for Hermite–Hadamard.
2. Preliminaries
For the sake of completeness, it will be better to explore and investigate the preliminary section due to the number of definitions. In this section, we will discuss some known concepts and definitions which we need in our investigation in further sections. We begin by introducing harmonic convex functions, p-harmonic convex functions and s-type convex functions. We conclude this section with recalling the m-polynomial convex function, which will be required in our studies.
Definition 1 ([
21]).
A function is said to be harmonic convex, ifholds for all and . Definition 2 ([
22]).
A function is said to be p–harmonic convex, ifholds for all and . Note that if we choose
in (
4), we get the following Jensen
p–harmonic convex function.
holds for all
.
If we choose , then p–harmonic convex functions reduce to classical harmonic convex functions.
Definition 3 ([
14]).
A function is said to be an s–type convex function ifholds ∀
, and Definition 4 ([
9]).
A nonnegative function is called m–poly convex function if for every and if Now, we recall the hypergeometric function [
23], which is defined by Euler in integral form:
3. New m–Poly p–Harmonic s–Type Convex Function and Its Properties
The concept of harmonic convexity and its applications have been intensively investigated for a long time by many researchers in numerous disciplines, and attention to this subject has grown tremendously. By making use of the concept of the harmonic convexity and integral inequalities, various estimations and refinements of them have been introduced, and authors have gained numerous perspectives in many research directions such as economics, probability, statistics, engineering and physics.
The objective goal of this section is to introduce a new family of harmonic convexity, namely m–poly p–harmonic s–type convex functions, and to discuss some of its algebraic properties. Further to enhance the quality and utility of this paper, we add lemmas and some interesting and amazing propositions. Some examples pertaining to this newly introduced idea are investigated.
Definition 5. A nonnegative real-valued function is called m–poly p–harmonic s–type convex, ifholds for every , and . Remark 1. Choosing in Definition 5, we obtain the following new definition for a p–harmonically s–type convex function: Choosing in Definition 5, we obtain new definition about m–poly harmonically s–type convex function: When we put , Definition 5, yields the definition of an m–poly s–type convex function, which is defined by İşcan (see [14]). When we put , and , Definition 5, yields the definition of a harmonically P–function (see [24]). When we put , and , Definition 5, yields the definition of a P–function [25]. When we put , and , Definition 5, yields the definition of a harmonically convex function, which is defined by İşcan (see [21]). When we put , and , Definition 5, yields the Definition (1). When we put and , Definition 5, yields the definition of an m–poly convex function, which is defined by Kadakal (see [9]). When we put and , Definition 5 yields the following new definition of a harmonically s–type convex function: When we put and , Definition 5, yields the definition namely s–type convex function, which is defined by İşcan (see [14]). The best part of this newly introduced definition is that, if we choose different values for m, s and p, it yields new inequalities and explains its relation with some classical established results.
Lemma 1. Let and , then the following inequalities and hold true for all .
Proof. The proof is evident. □
Proposition 1. Let be a p–harmonic convex set. Every p–harmonic convex function on a p–harmonic convex set is an m–poly p–harmonic s–type convex function.
Proof. Using the definition of
p–harmonic convex function and from the Lemma 1, since
and
for all
we have
□
Proposition 2. Every m–poly p–harmonic convex function is an m–poly p–harmonic s–type convex function.
Proof. Using the definition of
m–poly
p–harmonic convex function and from (Remark 3, see [
14]), we have
and
for all
and
.
□
Proposition 3. Every m–poly p–harmonic s–type convex function is a p–harmonic h–convex function with .
Remark 2. If we put in Proposition 2, then it yields the harmonically h–convex function, which was introduced by Noor et al. [26]. If we put in Proposition 2, then it yields the h–convex function, which was defined by Varošanec et al. [27]. Now, to enhance the stability of the newly introduced definition of m–poly p–harmonic s–type convex functions, we give some examples.
Example 1. If is a non-decreasing harmonic convex function and , then it is a p–harmonic convex function (see [28]). So, taking Proposition 1 into consideration, it is an m–poly p–harmonic s–type convex function. Example 2. Using the literature of a published paper (see [28]), we say that if is a non-decreasing harmonic convex function on and , then it is p–harmonic convex function. So, taking Proposition 1, into consideration it is an m–poly p–harmonic s–type convex function. Example 3. İşcan proved that in (see [28]), is p–harmonic convex function for . So, according to Proposition 1, it is an m–poly p–harmonic s–type convex function. Example 4. Every non-decreasing harmonic convex function and is p–harmonic convex function (see [28]). Therefore is p–harmonic for nonnegative values of x. So, taking Proposition 1, into consideration it is an m–poly p–harmonic s–type convex function. Now, before presenting our main results, we study some algebraic properties of the newly introduced function.
Theorem 1. Let If and are two m–poly p–harmonic s–type convex functions, then
- 1.
is m–poly p–harmonic s–type convex function.
- 2.
For nonnegative real numbers is an m–poly p–harmonic s–type convex function.
Proof. Let
and
be
m–poly
p–harmonic
s–type convex, then
Let
be
m–poly
p–harmonic
s–type convex, then
which completes the proof. □
Remark 3. (i) Choosing in Theorem 1, we get that and are p–harmonic s–type convex functions.
(ii) Choosing in Theorem 1, we get that and are m–poly harmonic s–type convex functions.
(iii) Choosing and in Theorem 1, we get that and are harmonic s–type convex functions.
(iv) Choosing in Theorem 1, we get that and are m–poly s–type convex functions.
(v) Choosing and in Theorem 1, we get that and are s–type convex functions.
Theorem 2. Let be a p–harmonic convex function and be a non-decreasing and m–poly s–type convex function. Then the function is m–poly p–harmonic s–type convex.
Proof. For all
and
we have
which completes the proof. □
Remark 4. (i) If we put in Theorem 2, then we obtain the following inequality (ii) If we put in Theorem 2, then we obtain the following inequality (iii) If we put and in Theorem 2, then we obtain the following inequality (iv) If we put in Theorem 2, then we obtain the following inequality (v) If we put and in Theorem 2, then we obtain the following inequality: Theorem 3. Let be a class of m–poly p–harmonic s–type convex functions and . Then is an m–poly p–harmonic s–type convex function and is an interval.
Proof. Let
and
then
which completes the proof. □
Remark 5. If we put and in Theorem 3, then we get Theorem (2.2) in [13]. 4. (H–H) Type Inequality for m–Poly p–Harmonic s–Type Convex Functions
The Hermite–Hadamard-type inequality was first studied for convex functions and has been examined and investigated extensively in different directions. This inequality plays an amazing role in the literature; no one can deny its applications and fruitful uses. Numerous extensions, generalizations and improvements have appeared in the literature of this inequality. Many researchers have collaborated on numerous concepts in the field of inequalities. This type of inequality has remained an area of great interest due to its widespread perspective and importance in the area of pure and applied sciences.
The purpose of this section is to derive a new inequality of the (H–H) type using m–poly p–harmonic s–type convexity. Further, some corollaries and remarks are presented.
Theorem 4. Let be an m–poly p–harmonic s–type convex function. If then Proof. Since
is
m–poly
p–harmonic
s–type convex function, we have
which leads to
Using a change of variables, we get
Integrating the above inequality with respect to
on
we obtain
which completes the left side inequality. For the right side inequality, changing the variable of integration as
and using Definition 5 for the function
, we have
which completes the proof. □
Corollary 1. Choosing in Theorem 4, then we get the following new H–H type inequality for p–harmonic s–type convex functions: Corollary 2. Choosing in Theorem 4, then we get the following new H–H type inequality for m–poly harmonic s–type convex functions: Corollary 3. Choosing in Theorem 4, then we get the following new H–H type inequality for m–poly s–type convex functions: Remark 6. Choosing and in Theorem 4, we get Theorem (2.5) in [29]. Remark 7. Choosing and in Theorem 4, we get Theorem (2.3) in [13]. Remark 8. Choosing and in Theorem 4, we get Theorem (4) in [9]. Remark 9. Choosing , and in Theorem 4, we get Theorem (3) in [30]. Remark 10. Choosing , and in Theorem 4, we get the simple H–H inequality in [2]. 5. Refinements of (H–H) Type Inequality
The main objective and goal of this section is to investigate and examine the refinements of H–H type inequality via the newly introduced idea, namely the m–poly p–harmonic s–convex function. Further, here a lemma, power mean and Hölder-type inequality will be required in our studies. We conclude this section by adding some corollaries.
Lemma 2 ([
31]).
Let be differentiable function on the of . If , thenwhere and Theorem 5. Let be a differentiable function on the of . If and is m–poly p–harmonic s–type convex function on , thenwhere, , , .
Proof. Using Lemma 2, the power mean inequality and
m–poly
p–harmonic
s–type convexity of the
we have
which completes the proof. □
Corollary 4. Under the assumptions of Theorem 5 with and , we have the following new result: Corollary 5. Under the assumptions of Theorem 5 with , we have the following new result:where Theorem 6. Let be a differentiable function on the of . If and is m–poly p–harmonic s–type convex function on , , thenwhere Proof. Considering the equality presented in Lemma 3, Hölder’s inequality and
p–harmonic
s–type convexity of the
we have
which completes the proof. □
Corollary 6. Under the assumptions of Theorem 6 with and , we have the following new result: Corollary 7. Under the assumptions of Theorem 6 with , we have the following new result:where 6. Ostrowski-Type Inequalities
The Ostrowski inequality expresses bounds on the deviation of a function from its integral mean. The great mathematician Ostrowski investigated his famous and popular inequality in 1938. This inequality has lot of applications in the field of numerical analysis, cumulative distribution functions, probability theory and approximation theory.
The main objective and goal of this section is to introduce a new lemma. On the basis of this newly introduced lemma, we make some refinements of the Ostrowski-type inequality with the help of the power mean and Hölder type inequality.
Lemma 3. Let be a differential mapping on and with and . If , then the following equality holds true. Proof. Integration by parts and changing variables of integration yields
□
Theorem 7. Let be a differentiable mapping on , where with and If is an m–poly p–harmonic s–type convex function on for and , then where
Proof. Considering the equality presented in Lemma 3, applying power-mean inequality and
m–poly
p–harmonic
s–type convexity of the
we have
This completes the proof. □
Theorem 8. Let be a differentiable mapping on , where with and If is an m–poly p–harmonic s–type convex function on for and , then
Proof. Considering the equality presented in Lemma 3 and applying Hölder’s inequality, we have
By using
m–poly
p–harmonic
s–type convexity of the
we have
This completes the proof. □
7. Applications
The main objective and goal of this section is to attain some new inequalities for the arithmetic, geometric and harmonic means. The following means are well-known and popular due to research background because these means have fruitful importance and magnificent applications in numerical approximation, machine learning, statistics and probability. The harmonic mean is a special case of the power mean. This mean has a lot of importance in numerous field of pure and applied sciences i.e., electric circuit theory, probability, finance, computer science, geometry, trigonometry and statistics. This mean equalizes the weights of each data point because this mean is the most appropriate measure for rates and ratios. In this section, we recall the following special means of two positive numbers with :
Proposition 4. Let and . Then we have the following inequality Proof. When we choose
for
, Theorem 4 yields the inequality (
14). □
Proposition 5. Let and . Then we have the following inequality Proof. When we choose
for
, Theorem 4 yields inequality (
15). □
Proposition 6. Let and . Then we have the following inequality Proof. When we choose
for
, Theorem 4 yields inequality (
16). □
Proposition 7. Let and . Then we have the following inequality Proof. When we choose
for
, Theorem 4 yields inequality (
17). □
Proposition 8. Let and . Then we have the following inequality Proof. When we choose
for
, Theorem 4 yields inequality (
18). □
Proposition 9. Let . Then we have the following inequality Proof. When we choose
for
, Theorem 4, yields inequality (
19). □
Proposition 10. Let . Then we have the following inequality Proof. When we choose
for
, Theorem 4 yields inequality (
20). □
8. Conclusions
The theory of convex analysis and integral inequalities are fruitful and have amazing applications in statistical problems, statistical theory, optimization theory, probability, functional analysis, physics and numerical quadrature formulas. In this article,
- (1)
we addressed a novel idea of generalized harmonic convex function, namely m–polynomial p–harmonic s–type convex function.
- (2)
Some nice algebraic properties of the proposed definition are examined.
- (3)
In the mode of the newly proposed definition, we investigated a new sort of H–H-type inequality.
- (4)
In addition, we obtained refinements of the H–H type inequality.
- (5)
Further, a new lemma is presented. By considering this new lemma, several refinements and remarkable extensions of the Ostrowski type inequality are established.
- (6)
Some applications to special means are attained as well.
In the future, we hope the results of this paper and the new idea can be extended in different directions such as fractional calculus, quantum calculus and time scale calculus.
Author Contributions
Conceptualization, M.T., S.K.S.; methodology, S.K.S., M.T., S.K.N. and O.M.A.; software, S.K.S. and M.T.; validation, S.K.S., M.T, S.K.N. and A.A.S.; formal analysis, M.T., S.K.S., O.M.A. and K.N.; investigation, M.T., S.K.S. and S.K.N.; resources, S.K.S.; data curation, M.T., O.M.A., A.A.S. and K.N.; writing—original draft preparation, S.K.S. and M.T.; writing—review and editing, S.K.S. and M.T.; supervision, S.K.N. and A.A.S. and K.N.; project administration, M.T., S.K.S., K.N.; funding acquisition, K.N. All authors have read and agreed to the published version of the manuscript.
Funding
This research was supported by the Fundamental Fund of Khon Kaen University, Thailand.
Data Availability Statement
Not applicable.
Conflicts of Interest
The authors declare no conflict of interest.
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