1. Introduction
In recent years, numerous scholars in analysis and various branches of mathematics have shown a growing interest in inequality theory [
1,
2]. Many real-world problems can be viewed as integral equations, emphasizing the importance of generalizing integral inequalities to address such issues [
3].
In Moore’s renowned book, the introductory chapter provides an interactive exploration of numerical data, serving as an initiation to interval analysis in numerical analysis (refer to [
4]). Over the last five decades, numerous applications have emerged across various domains, including interval differential equations, computer graphics, aero elasticity, and optimization of neural networks. Recently, several authors have extensively investigated various integral inequalities within the context of interval-valued functions (refer to [
5,
6,
7]).
It is widely acknowledged that the convexity of functions plays a pivotal role in numerous scientific disciplines, encompassing probability theory, economics, and optimal control theory. Moreover, various inequalities have been extensively documented in the literature (refer to [
8,
9]). The subsequent inequality is commonly known as the classical Hermite-Hadamard inequality regarding equality:
If
is a convex function defined on the interval
of real numbers, and
with
, then
Both inequalities are valid in the opposite direction if f exhibits concavity.
Varosanec initially introduced the concept of ℎ-convexity in 2007 (refer to [
10]), exploring various generalizations and extensions of this inequality (refer to [
11]). Several authors have subsequently developed more intricate Hermite-Hadamard inequalities involving ℎ-convex functions (refer to [
12,
13]). Moreover, Costa proposed a Jensen-type inequality for fuzzy interval-valued functions (refer to [
14]). In the realm of interval-valued functions, Zhao et al. presented a novel Hermite-Hadamard inequality for ℎ-convex functions (refer to [
15]).
Using the ℎ-Godunova–Levin function (refer to [
16,
17]), Almutairi and Kiliman demonstrated the following inequality in 2019.
If
is a convex function defined on the interval
of real numbers, and
with
, then
where,
such that
.
Several mathematicians have expanded upon the Ostrowski inequality in various directions. Notably, several scientific articles have delved into this topic, exploring different forms of convexity. For instance, İşcan et al. [
18] investigated the concept of a harmonically
s-convex function. Set [
19] introduced the fractional version of the Ostrowski-type inequality using Riemann–Liouville fractional operators. Liu [
20] utilized the equality established by Set to devise new refinements of the Ostrowski-type inequality for an MT-convex function. Tunç [
21] examined the Ostrowski-type inequality for an ℏ-convex function. Ozdemir et al. [
22] derived a fresh version of the Ostrowski-type inequality for an (α, m)-convex function. Agarwal et al. [
23] explored a more generalized Ostrowski-type inequality using a Raina fractional integral operator. Sarikaya et al. [
24,
25] employed local fractional integrals to establish new generalizations of the Ostrowski-type inequality. Gürbuz et al. [
26,
27] utilized a Katugampola fractional operator for a generalized version of the Ostrowski inequality. Ahmad et al. [
28,
29] introduced some innovative generalizations of the Ostrowski inequality via an Atangana–Baleanu fractional operator for differentiable convex functions and for harmonical convexity, see [
30,
31,
32,
33]. For further details on recent advancements in the Ostrowski-type inequality, readers are referred to the following references (refer to [
34,
35,
36]). Budak et al. [
37] derived innovative fractional inequalities of the Ostrowski type for interval-valued functions, drawing on the definitions of gH-derivatives. Basic concepts related to fuzzy and fuzzy Aumman’s integral are in the following literature (see [
38,
39] and the references therein). Nanda [
40] introduced the concept of convexity in fuzzy environment. For interval-valued convex mapping, see [
41]. Khan et al. [
42] introduced log-h-convex fuzzy-interval-valued functions as a distinct class of convex fuzzy-interval-valued functions, employing a fuzzy order relation. This class facilitated the establishment of Jensen and Hermite-Hadamard inequalities (see [
43,
44,
45,
46,
47] and the references therein).
Naturally, numerous researchers have extensively explored and examined Ostrowski’s and Hermite-Hadamard inequalities in a novel context via newly defined class of
·
–Godunova–Levin convex fuzzy-number mappings. Consequently, several extensions and improvements have been developed. For example, refer to [
15,
39,
40,
47] and the references therein. In this investigation, we propose some further adjustments to Fejér, Pachpatte, and Ostrowski’s integral inequalities via
·
-
–Godunova–Levin convexity and fuzzy Aumman’s integrals.
2. Preliminaries
Consider
as the set comprising all closed and bounded intervals of
, and let
belong to
, defined as:
It is named a positive interval
if
. The Definition of
, which represents the set of all positive intervals, is
Let
and
be defined by
Subsequently, the Minkowski difference
, addition
, and multiplication
for
belong to
are delineated as follows:
Remark 1. (i) For given the relation defined on by if and only if for all is a partial interval inclusion relation. The relation is coincident to on It can be easily seen that “” looks like “up and down” on the real line so we call “up and down” (or “” order, in short) [
44]
. For the Hausdorff–Pompeiu distance between intervals and is defined by It is a familiar fact that is a complete metric space [
37,
38,
39].
We will briefly review some essential concepts regarding fuzzy sets and fuzzy numbers since we will rely on the standard definitions of these sets.
Please note that we refer to and as the set of all fuzzy subsets and fuzzy numbers of .
Given , the level sets or cut sets are given by for all and by . These sets are known as -level sets or -cut sets of , see [
37].
Proposition 1 ([44]). Let . Then, relation is given on by when and only when , for every which are left- and right-order relations.
Proposition 2 ([44]). Let . Then, relation is given on by when and only when for every which is the order relation on .
Remember the approaching notions, which are offered in the literature. If and , then, for every the arithmetic operations addition “, multiplication “, and scaler multiplication “ are defined byover .
Aumann Integrals for Interval and Fuzzy Number Mappings
Now we define and discuss some properties of Aumann integrals for interval and ··s.
Definition 1 ([37]). If is an interval-valued mapping () satisfying that , then is an Aumann integrable over when and only when and both are lebesgue integrable over such that The literature suggests the following conclusions, see [
37,
38,
47]:
Definition 2 ([44]). A fuzzy-interval-valued map is named ···. For each its s are classified according to their -levels are given by for all Here, for each the end point real mappings are called lower and upper mappings of .
Definition 3. Let be an ···. Then, fuzzy integral of over denoted by , is given level-wise byfor all where denotes the collection of Riemannian integrable mappings of s. The ··· is -integrable over if Note that, if are Lebesgue-integrable, then is fuzzy Aumann-integrable mapping over , see [
44].
Theorem 1 ([39]). Let be an ···, it’s s are classified according to their -levels are given by for all and for all Then, is -integrable over if and only if, and are both -integrable over . Moreover, if is -integrable over then for all For all denotes the collection of all -integrable ···s The family of all -integrable ··s over are denoted by
Breckner discussed the coming emerging idea of interval-valued convexity in [
41].
A ·· is called convex ·· iffor all , where is the collection of all real valued intervals. If (16) is reversed, then is called concave. Definition 4 ([40]). The ·· is called convex ·· on iffor all where for all If (17) is reversed then, is called concave ·· on .
is affine if and only if it is both convex and concave ··.
3. Hermite-Hadamard Inequalities over ·--Godunova–Levin Convex ··
In this section, we start with the main Definition of ·--Godunova–Levin convexity over fuzzy domain that will be helpful for the upcoming results. The fuzzy valued Hermite-Hadamard inequalities for ·--Godunova–Levin convex ··s are established in this section. Additionally, several instances are provided to support the theory produced in this study’s application.
Definition 5. Let be convex set and such that . Then ·· is said to be ·--Godunova–Levin convex on iffor all where The ·· is said to be ·--Godunova–Levin concave on if inequality (21) is reversed. Moreover, is known as ·--Godunova–Levin affine ·· on iffor all where Remark 2. The ·--Godunova–Levin convex ··s have some very nice properties similar to convex ··.
- (1)
if is ·--Godunova–Levin convex ··, then is also ·--Godunova–Levin convex for .
- (2)
if and both are ·--Godunova–Levin convex ··s, then is also ·--Godunova–Levin convex ··.
Here, we will go through a few unique exceptional cases of · -Godunova–Levin convex ··s:
- (i)
If then ·--Godunova–Levin convex ·· becomes ·--Godunova–Levin convex ··, that is - (ii)
If then ·--Godunova–Levin convex ·· becomes ·-Godunova–Levin convex ··, see [
46]
, that is - (iii)
If then ·--Godunova–Levin convex ·· becomes ·-Godunova–Levin ··, that is Note that, there are also new special cases (i) and (iii) as well.
Theorem 2. Let be convex set, non-negative real valued function such that and let be a ··, it’s s are classified according to their -levels such that, are given byfor all and for all . Then is ·--Godunova–Levin convex on if and only if, for all is -Godunova–Levin convex and is -Godunova–Levin concave. Proof. Assume that for each
and
are
-Godunova–Levin convex and
-Godunova–Levin concave on
, respectively. Then, we have
and
Then by (18), (5) and (6), we obtain
that is
Hence, is ·--Godunova–Levin convex ·· on .
Conversely, let
is
·
-
-Godunova–Levin convex
·
·
on
Then, for all
and
we have
Therefore, from (23), we have
Again, from (18), (5) and (6), we obtain
for all
and
Then by
·
-
-Godunova–Levin convexity of
, we have for all
and
such that
and
for each
Hence, the result follows. □
Remark 3. If with then ·--Godunova–Levin convex ·· reduces to the ·--Godunova–Levin convex function.
If with and with , then ·--Godunova–Levin convex ·· reduces to the -Godunova–Levin convex function.
If with and , then ·--Godunova–Levin convex ·· reduces to the -Godunova–Levin convex function.
If with and , then ·--Godunova–Levin convex ·· reduces to the -convex function.
Example 1. We consider for and the ·· defined by Then, for each we have . Since end point functions are -Godunova–Levin convex and -Godunova–Levin concave functions for each , respectively. Hence is ·--Godunova–Levin convex ··.
Definition 6. Let be a ··, it’s s are classified according to their -levels such that, are given byfor all and for all . Then, is lower -Godunova–Levin convex (upper -Godunova–Levin concave) ·· o n if and only if, for all is a -Godunova–Levin convex (-Godunova–Levin concave) mapping and is a -Godunova–Levin affine mapping. Definition 7. Let be a ··, it’s s are classified according to their -levels such that, are given byfor all and for all . Then, is an upper -Godunova–Levin convex (-Godunova–Levin concave) ·· on if and only if, for all is an -Godunova–Levin affine mapping and is a -Godunova–Levin convex (-Godunova–Levin concave) mapping. Remark 4. If , then both concepts “·--Godunova–Levin convex ··” and “-Godunova–Levin convex ··”, are behave alike when is lower ·--Godunova–Levin convex ··.
Both concepts “·--Godunova–Levin convex fuzzy number mapping”, and “-Godunova–Levinconvex interval-valued mapping” are coincident when is lower -Godunova–Levin convex ·· with .
The following result discuss the Hermite-Hadamard inequality over ·--Godunova–Levin convex ··.
Theorem 3. Let be a ·--Godunova–Levin convex ·· with non-negative real valued function and , it’s s are classified according to their -levels such that, are given by for all and for all . If , then If is -Godunova–Levin concave ··, then (25) is reversed. Proof. Let
be a
·
-
-Godunova–Levin convex
·
·
. Then, for
, we have
If
, then we have
Let
and
. Then, above inequality we have
Therefore, for every
, we have
In a similar way as above, we have
Combining (27) and (28), we have
Hence, the required result.
Note that, by using same steps, the Formula (26) can be proved with the help of -Godunova–Levin concave ··. □
Remark 5. If , then Theorem 3 simplifies to the outcome for ·--convex ·· which is also new one: If , then Theorem 3 simplifies to the outcome for ·-convex ·· which is also new one: If then Theorem 3 simplifies to the outcome for ·--·· which is also new one: If with and , then Theorem 3 simplifies to the outcome for classical convex function, see [
15]:
If with , then Theorem 3 simplifies to the outcome for classical -convex function, see [
46]:
If with and , then Theorem 3 simplifies to the outcome for classical -convex function, see [
46]:
If with and , then Theorem 3 simplifies to the outcome for classical convex function: If with and , then Theorem 3 simplifies to the outcome for classical -convex function: Example 2. We consider for , and the ·· defined by, Then, for each we have . Since left and right end point mappings , are ·--Godunova–Levin convex mappings for each , then is -Godunova–Levin convex ··. We clearly see that . Now computing the followingfor all That means Similarly, it can be easily show thatfor all such that From which, we havethat isfor all Theorem 4. Let be a ·--Godunova–Levin convex ·· with non-negative real valued function and it’s s are classified according to their -levels such that, are given by for all and for all . If , then If is a -Godunova–Levin concave ··, then (38) is reversed.whereand , Proof. Take
we have
Therefore, for every
, we have
In consequence, we obtain
In a similar way as above, we have
Combining (40) and (41), we have
By using Theorem 3, we have
Therefore, for every
, we have
that is
hence, the result follows. □
Example 3. We consider for , and the ·· defined by, as in Example 2, then is ·--Godunova–Levin convex ··. We have and . We now compute the following: Hence, Theorem 4 is verified.
The novel fuzzy Hermite-Hadamard inequalities for the product of two ·--Godunova–Levin convex ··s are found in the results.
Theorem 5. Let be two ·--Godunova–Levin convex ··s with non-negative real valued functions and it’s s are classified according to their -levels such that, are given by and for all and for all . If and , then If is -Godunova–Levin concave ··, then (42) is reversed.where and and Proof. Let
be two
·
-
-Godunova–Levin convex and
·
-
-Godunova–Levin convex
·
·
s. Then, we have
and
and
From the Definition of
·
-
-Godunova–Levin convex
·
·
it follows that
and
, so
Integrating both sides of above inequality over
we get
Thus,
and Theorem 5 has been established. □
Example 4. We consider for , and the ··s defined by, Then, for each we have and Since end point functions and , -Godunova–Levin convex functions for each . Hence both are ·-,·--Godunova–Levin convex ··s, respectively. We now computing the followingfor each that means Hence, Theorem 5 is demonstrated.
Theorem 6. Let be two ·--Godunova–Levin convex and ·-- Godunova–Levin convex ··s with non-negative real valued functions , respectively and respectively, it’s s are classified according to their -levels such that, are given, respectively, by and for all and for all . If , thenwhere and and Proof. By hypothesis, for each
we have
Integrating over
we have
that is
Hence, the required result. □
Example 5. We consider for , and the ··s as in Example 4. Then, for each we have and and, are ·--Godunova–Levin convex and ·--Godunova–Levin convex ··s, respectively. We have and ,. We now computing the followingfor each that meanshence, Theorem 6 is demonstrated. The H-H Fejér inequalities for ·--Godunova–Levin convex ··s are now presented. The second H-H Fejér inequality for ·--Godunova–Levin convex ·· is first obtained.
Theorem 7. Let be an ·--Godunova–Levin convex ·· with , it’s s are classified according to their -levels such that, are given by for all and for all . If and symmetric with respect to then Proof. Let
be an
·
-
-Godunova–Levin convex
·
·
. Then, for each
we have
After adding (46) and (47), and integrating over
we get
Since
is symmetric, then
Then from (49), (48) we have
that is
hence
Now, generalizing the first H-H Fejér inequalities for classical Godunova–Levin convex functions and we build the first H-H Fejér inequality for ·--Godunova–Levin convex ··. □
Theorem 8. Let be an ·--Godunova–Levin convex ·· with , it’s s are classified according to their -levels such that, are given by for all and for all . If and symmetric with respect to and , then Proof. Since
is an
·
-
-Godunova–Levin convex, then for
we have
Since
, then by multiplying (51) by
and integrate it with respect to
over
we obtain
Then from (53) and (54), (52) we have
from which, we have
that is
This completes the proof. □
Remark 6. From Theorem 7 and 8, we clearly see that:
If , then we acquire the inequality (25).
Let and . Then from (45) and (50), we acquire the following inequality, see [
45]:
If is lower Godunova–Levin convex ·· on and then we derive the following subsequent inequality, see [
33]:
If is lower Godunova–Levin convex ·· on with and then from (45) and (50) we derive the following subsequent inequality, see [
15]:
If is lower Godunova–Levin convex ·· on with and , then from (45) and (50) we derive the following subsequent inequality, see [
15]:
Let and with . Then from (45) and (50), we obtain following classical Fejér inequality. Example 6. We consider for , and the ·· defined by, Then, for each we have . Since end point mappings are -Godunova–Levin convex mappings for each , then is ·--Godunova–Levin convex ··. Ifthen , for all . Since and . Now we compute the following: From (61) and (62), we havefor all Hence, Theorem 7 is verified. From (63) and (64), we have Hence, Theorem 8 has been verified.
4. Fuzzy Version of Ostrowski’s Type Inequality via ·--Godunova–Levin ··s
Here, an Ostrowski-type inequality was formulated in conjunction with several illustrations for Godunova-Levin functions within a broader category.
First, recalling some basic notations that will be helpful in this section such that:
Gamma and Beta functions are respectively characterized as
for
for
,
.
The integral representation of the hypergeometric function is
for
,
,
.
The subsequent lemma aids in achieving our goal.
Lemma 1. Let be a differentiable function on with , where . If is integrable over , then Proof. Integration by parts finalizes the proof. □
Now, employing Lemma 1, we derive the principal outcomes.
Theorem 9. Let be a differentiable function on with , where and let be a integrable over . If is -Godunova–Levin ··s, with . If then for all where and .
Proof. In accordance with Lemma 1 and
is
-Godunova–Levin
·
·
, for
we have
and
From above equations, we have
and
As a result, we obtain
and
That is,
this completes the proof. □