1. Introduction
Mathematics is a fundamental field of scientific inquiry that influences all areas of life. It combines various sub-fields, with fixed-point theory as a key area in pure and applied mathematics. This theory is broad and adaptable, with applications in numerous disciplines, including mathematical economics, approximation theory, variational inequalities, management, game theory, social sciences, and optimization theory. Over the last 50 to 60 years, fixed-point theory has rapidly become a prominent dynamic and intriguing field of mathematical research. The foundational work in this area began with Poincare [
1], who first explored fixed-point theory in 1886. Subsequently, Banach [
2] proved in 1922 that contraction mappings in a complete metric space have a unique fixed point. The following is the formulation of the Banach fixed-point theorem.
Consider a metric space
and a contraction mapping
. For any
there exist
such that
Under these conditions, T possesses a unique fixed point. In the early phases of fixed-point theory, the Banach contraction principle is acknowledged as a fundamental concept, advancing many subsequent fixed-point theorems.
A significant branch of fixed-point theory is metric fixed-point theory, with applications extending beyond mathematics into other fields. The origins of metric fixed-point theory can be traced back to Banach’s contraction principle introduced in 1922. When this principle falls short, researchers have developed various generalized metric spaces and contraction principles, leading to the establishment of numerous fixed-point theorems. Examples include quasi-metric spaces, which omit the symmetry axioms [
3], and semi-metric spaces, which do not require the triangle inequality [
4]. Further, partial metric spaces allow for the possibility that the distance between the point and itself does not necessarily need to be zero [
5]. In the academic literature, several generalizations of metric spaces have been introduced, including
F-metric,
b-metric, and modular metric spaces, where numerous theorems concerning fixed points and common fixed points have been formulated [
6,
7,
8,
9,
10,
11,
12,
13]. The idea of a 2-metric was presented by Gahler [
14], derived from geometry involving more than two points, and, subsequently, the topological properties of 2-metric spaces were explored by Lahiri et al. [
15]. The idea of
G-metric, a generalized metric space based on the geometry of three points, was proposed by Mustafa and Sims [
16]. Branciari [
17] extended the traditional metric by replacing the standard triangle inequality with four four-point conditions, leading to the notion of a rectangular metric. Additionally, Choi et al. [
18] introduced the g-metric with degree
n, which characterizes a distance measure involving
points. This advancement expands on the traditional distance metrics that involve only two points, and the g-metric incorporates three points.
The concept of an
m-hemi metric defined on a set containing at least
elements, where
m is an integer, was proposed by Deza and Rosenberg [
19]. This innovative concept has garnered significant attention from researchers. Studies have explored various topological properties and fixed-point theorems connected to Banach’s contraction principle and its generalizations for mappings defined on
m-hemi metric spaces [
20].
The idea of cone metric spaces has also garnered considerable interest from researchers. Huang and Zhang [
21] were the pioneers in defining cone metric spaces. Rzepecki [
22] offered a similar interpretation and, after a detailed exploration of convergence and completeness in these spaces, established multiple fixed-point outcomes for contractive mappings. Later, Liu and Xu [
23] extended the idea of cone metric spaces to Banach algebras and applied the Banach contraction principle within this framework. See [
24,
25,
26,
27] for more related studies. Ali et al. [
28] worked on the approximation of fixed points and the solution of a nonlinear integral equation. Özger et al. [
29] proved several fixed-point results and determined the existence and uniqueness of Fredholm-type integral equations by utilizing fixed-point theorems. Firozjah et al. [
30] worked on the concept of cone b-metric spaces over Banach algebras and obtained several fixed-point results without the condition of normality of cones. Huang et al. [
31] discussed some topological properties and fixed-point results in cone metric spaces over Banach algebras. Firozjah et al. [
32] proved several fixed-point results under generalized c-distance in cone b-metric spaces over Banach algebras. Huang et al. [
33] generalized a famous result for a Banach-type contractive mapping from
to
in a cone b-metric space over Banach algebra with coefficient
, where
is the spectral radius of the generalized Lipshitz constant
k. Du and Karapınar [
34] investigated the answer to the question regarding whether the results in cone b-metric spaces generalize the existing ones or are equivalent to them. Janković et al. [
35] shortened the proofs of fixed-point results in cone metric spaces when the cone is normal and solid. Zabrejko [
36] provided a brief overview of fixed-point theorems that extend the Banach–Caccioppoli principle for contractive mapping. Further, they established the presence and uniqueness of fixed points for operators in
K-metric or
K-normed linear spaces, including local convex spaces and Banach space scales.
In this paper, we present the idea of a cone m-hemi metric space as a generalization of the m-hemi metric space and explore its topological properties. Our main goal is to use complete and compact cone m-hemi metric spaces to prove fixed-point theorems.
The structure of this paper is organized as follows:
Section 2 introduces the fundamental definitions and examples related to the Banach algebras, metric spaces, cones, cone metric spaces, and
m-hemi metric spaces, along with relevant examples for the subsequent sections.
Section 3 focuses on proving fixed points by utilizing the Banach contraction principle and Krasnoselskii, Meir–Keeler, and Boyd–Wong contraction mapping principles in a complete normal cone
m-hemi metric space. This section also includes essential definitions, lemmas, and examples pertinent to our study.
Section 4 applies the results to Fredholm integral equations and integral equations in dynamic market equilibrium economics to demonstrate the applicability of our main findings. In conclusion, we summarize the key points of the paper.
2. Preliminaries
First, we review some fundamental concepts related to Banach algebra and cone
m-hemi metric spaces that are required for the subsequent parts. While researching function spaces, Frechet [
24] was the pioneer to introduce the concept of metric space. A function that describes the idea of distance between any two nonempty sets is called a metric.
Definition 1 ([25]). In metric spaces, an ordered pair represent a set , and Δ is a metric on , often known as a distance function on . This function is defined regarding , and, for every we have
- (S1)
Δ is finite, non-negative, and real-valued;
- (S2)
if and only if ;
- (S3)
(symmetry);
- (S4)
(triangular inequality).
The sign × stands for the Cartesian product of sets. For the sets , the Cartesian product consists of all the possible ordered pairs , where Therefore, refer to the set of all the ordered pairs formed by elements from .
Example 1 ([25]). Define the function as follows: Therefore, Δ is a metric on the real numbers set
To demonstrate that Δ
is indeed a metric on the conditions to are straightforward. We only need to verify the condition Let This demonstrates that Δ is a metric on the set of
Definition 2 ([26]). If a Banach space ϝ has a multiplication that meets certain properties, it is called a Banach algebra. These properties are as follows: for all ,
- (1)
- (2)
- (3)
- (4)
Existence of such that
- (5)
- (6)
When there is in such a manner that then an element is considered to be invertible.
Example 2. The set of complex numbers and the set of real numbers , each equipped with their respective norms defined by absolute values, are both Banach algebras.
Definition 3 ([27]). A subset ρ of real Banach algebra ϝ is called a cone if it satisfies the following conditions:
- (i)
;
- (ii)
- (iii)
For a cone
we establish a partial order ≤ on
relative to
as follows:
if and only if
We use
to denote
with
and
to indicate that
;
indicates the interior of
The cone
is referred to as normal if there exists a number
such that, for all
The least positive number that meets the condition above is referred to as the normal constant of . In the subsequent discussion, we assume that is a real Banach algebra, is a cone in with , and ≤ denotes the partial ordering associated with .
If every increasing sequence with upper bounds converges, the cone
is referred to as regular. Specifically, if
is a sequence such that
there are
such that
for some
Equivalently, if every decreasing sequence with lower bounds converges, the cone
is referred to as regular. It is widely recognized that a regular cone is also a normal cone.
Definition 4 ([23]). Assume that is a nonempty set. The mapping must meet the following conditions:
- (1)
for all with and if and only if
- (2)
- (3)
Then, Δ is considered to be a cone metric on along with the pair , known as a cone metric space over Banach algebra
Example 3 ([21]). Suppose represents a constant. Therefore, is said to be a cone metric space.
Definition 5 ([19]). Assume and E is a set containing at least elements. Δ: is known m-hemi metric if at all possible
- 1.
(non-negativity);
- 2.
Δ for any (zero-conditioned);
- 3.
for any rearrangements π of the set (totally symmetric);
- 4.
(m-simplex inequality).
Then, called an m-hemi metric space.
The notion of the m-hemi metric serves as a generalization to extend the idea of the semi-metric for the m parameters. An important specific instance of the m-hemi metric is the scenario in which 2.
A function
is referred to as a 2-metric if
meets the conditions
of Definition 5 and the following tetrahedron inequality,
3. Main Results
In cone m-hemi metric space, we formulate a unique fixed-point theorem for contraction mappings and a generalized contraction principle. In addition, we provide a few non-trivial examples to validate our primary findings. Further, we provide some definitions and prove the necessary lemmas.
Definition 6. Assume and E is set to contain at least elements. Δ: (Banach algebra) is called cone m-hemi metric if at all possible
- 1.
(non-negativity);
- 2.
Δ for any (zero-conditioned);
- 3.
for any rearrangements π of the set (totally symmetric);
- 4.
(m-simplex inequality).
Then, is called a cone m-hemi metric space.
Now, we discuss that, if is a cone m-hemi metric, then is also a cone m-hemi metric on E.
Lemma 1. Let Δ be a cone m-hemi metric on E and then be a cone m-hemi metric on E.
Proof. The non-negativity of
ensures the non-negativity
. Furthermore, the identity implies axiom
and total symmetry
and the fact that
exhibits zero-conditioned and totally symmetric aspects. Therefore, we need to demonstrate that
satisfies axiom
.
Because
is strictly increasing in
, and since
axiom
, we have
Moreover, for each
, the following inequality holds
By adding (
3) to all
and then combining the result with inequality (
2), the proof is concluded. □
Now, we examine if is a cone m-hemi metric, and then is also a cone m-hemi metric on E.
Lemma 2. Let Δ be a cone m-hemi metric on E, and then is a cone m-hemi metric on E.
Proof. The properties of non-negativity, axiom , and symmetry for can be derived from the corresponding properties . Therefore, we need to verify that satisfies axiom .
We will examine the different scenarios.
Assume there exists
such that
Therefore, we can assume that, for every
, the following hold:
Suppose
. In this case, we have for all
and this implies that
satisfies axiom
.
Next, suppose
. Moreover, suppose there is an
such that
. In this case, we have
Therefore, suppose that
for all
. Finally, since
satisfies axiom
, we have
This concludes the proof. □
Example 4. Here, is cone m-hemi metric space but not m-hemi metric space because in a standard cone m-hemi metric space distance function Δ required to map to .
Definition 7. Consider to be a cone m-hemi metric space. For and is known as x-open ball with radius ε and centers at . The topology on E defined by using all x-balls as a sub-basis is referred to as the m-hemi metric topology and is indicated by . Elements of are termed x-open sets, while their complements are called x-closed sets.
Lemma 3. Let and let be a cone m-hemi metric space. If and only if , then W is an x-open set. There are finite numbers of points and for every
Proof. The claim’s appropriateness is apparent as the intersection of x-balls is x-open, indicating that the condition is instantly satisfied.
Conversely, let
and
W be an
x-open set. Subsequently,
x-open balls
exist such that
. Given that
and
, then
and
. For
, choose
Afterward, we possess
This concludes the proof. □
Definition 8. Given a cone m-hemi metric space and a subset W, its x-closure, represented by , is defined as the x-closure of W with regard to the topology τ.
Definition 9. Consider a cone m-hemi metric space , and ρ denotes a normal cone, where the normal constant is k. In E, let be the sequence.
- 1.
is said to be x-convergent to a if and only if Therefore, if and only if converges to y with regard to topology τ, it is x-convergent to y.
- 2.
A sequence is called x-Cauchy if and only if - 3.
is called x-complete if each x-Cauchy sequence in E is x-convergent.
- 4.
A mapping T is considered to be x-continuous on E if when .
Proposition 1. Let be sequence in E and be a cone m-hemi metric space.
- (i).
converges to such that - (ii).
For each , so that if is x-Cauchy sequence.
Now, we provide the lemma on the uniqueness of the limit in cone m-hemi metric space.
Lemma 4. The limit in cone m-hemi metric space is unique.
Proof. Consider denotes a normal cone, where the normal constant is k, and let be a cone m-hemi metric space. In E, let be an x-convergent sequence. Assume that are both the limits of the sequence . Thus, we obtain for all that there exist such that and there exist such that . Let .
Using
m-simplex inequality for all different elements
, for
,
Hence, . Since is arbitrary, . Thus, . □
Definition 10. A cone m-hemi metric space is considered to be compact if each sequence in E contains a convergent subsequence.
Now, we prove the Banach contraction principle in the context of cone m-hemi-metric spaces.
Theorem 1. Let be an x-complete cone m-hemi-metric space and ρ denote a normal cone, where the normal constant is k and represent an x-continuous self mapping that satisfiesfor all , . Then, T has a unique fixed point. Proof. Let
and
be any point. We define a sequence
. From (
6), we have
Given that
is a normal cone with a normal constant
k, it follows that
Hence,
is an
x-Cauchy sequence. As
is
x-complete, there exist a
with
. By
x-continuity of
T,
and by
and limit’s uniqueness
.
We now demonstrate the fixed point’s uniqueness. Assume that
T has distinct fixed point
with
for
. By (
6), we have
which contradicts
. As a result,
T possesses a unique fixed point. □
Corollary 1. Consider to be a complete cone m-hemi metric space, and ρ represents a normal cone, where the normal constant is k. For with and set = Suppose is a mapping that satisfies the contractive conditionfor all , , which is a constant. Moreover, assume that Then, T possesses a unique fixed point in Proof. We just have to demonstrate that is complete and for all y in .
Suppose
is a Cauchy sequence in
Then,
is also a Cauchy sequence in
E. Due to the completeness of
E, there is
so that
We have
Hence, and
Therefore,
is complete. For every
we have
Since it implies Hence, □
Corollary 2. Let be a complete cone m-hemi metric space. Let ρ represent a normal cone, where the normal constant is Consider a mapping x-continuous that satisfies for some positive integer u Where is a constant. Then, T possesses a unique fixed point in E.
Proof. According to Theorem 1 possesses a unique fixed point, which we denote as However, so is a fixed point of as well. Therefore, , indicating that is a fixed point of As the fixed point of T is also a fixed point of , the fixed point T is unique. □
Example 5. Let . Define and Then, Δ
is an x-complete cone m-hemi metric space on E. Then, (6) is satisfied and T possesses a unique fixed point, which is 0. We depict the graphical behavior of Δ
in Figure 1. Now, we prove the fixed-point theorem for compact cone m-hemi metric spaces.
Theorem 2. Consider as a sequentially compact cone m-hemi metric space, and ρ represents a regular cone. Assume that the mapping represents an x-continuous self mapping that satisfies the contractive condition Then, T possesses a unique fixed point in E.
Proof. Let
and
be any point. We define a sequence
In the case that, for some
u,
serves as a fixed point of
concluding the proof. Accordingly, we assume for all
u that
Define
and then
Therefore,
is a decreasing sequence with a lower bound of 0. Since
is a regular, there exists is
such that
Due to the sequence compactness of
E, there is a sub-sequence
of
and
such that
. It follows that
So,
where
k denotes the normal constant of
. By
x-continuity of
Moreover, by
and limit’s uniqueness,
.
We now demonstrate the fixed point’s uniqueness. Suppose that
T has the distinct fixed point
with
for
From (
7), we have
which is a contradiction. As a result,
T possesses a unique fixed point. □
Example 6. Consider . Define and This example demonstrates that the mapping on the sequentially compact cone m-hemi metric space with satisfies the contractive condition, and T possesses a unique fixed point at
Definition 11. Consider a metric space . A mapping is referred to as a Krasnosalskii mapping if given there exists such thatwhenever Now, we prove the Krasnosalskii fixed-point theorem in the setting of cone m-hemi metric spaces.
Theorem 3. Let be a complete cone m-hemi metric space and ρ denote a normal cone, where the normal constant is A mapping represent an x-continuous self-mapping that satisfies a Krasnosalskii condition if given there exist such thatwhenever Then, T possesses a unique fixed point. Proof. We show that
T is contractive. Let
and let
Since
T is Krasnosalskii, there exists
is contractive. Now, let
and
be any point. We define a sequence
.
Given a normal cone
with normal constant
k, it follows that
Hence,
is an
x-Cauchy sequence. Since
is
x-complete, there exist a
with
. By
x-continuity of
T,
and by
and limit’s uniqueness
.
Now, we demonstrate the fixed point’s uniqueness. Assume that
T has distinct fixed points
with
for
. By using (
8), we deduce
which contradicts
. As a result,
T has a unique fixed point. □
Example 7. Consider ϝ to be a Banach algebra which consists of all continuous real-valued functions. Let . Then, represents a normal cone, where the normal constant Consider , define , and , This example demonstrates that the mapping on the complete cone m-hemi metric space satisfies the Krasnosalskii condition with , so T possesses a unique fixed point at .
Definition 12. Consider is a metric space and Thus, T is said to satisfy the Meir–Keeler contractive condition if for given so that Now, we prove fixed-point theorem for Meir–Keeler contraction in the setting of cone m-hemi metric spaces.
Theorem 4. Let be a complete cone m-hemi metric space and ρ represent a normal cone, where the normal constant is Let represent a x-continuous self-mapping that fulfills the Meir–Keeler contractive condition if for given so that Then, T possesses a unique fixed point.
Proof. We demonstrate that
T is contractive. Let
and then
. Since
T satisfies the Meir–Keeler contractive condition,
such that
⇒
T is contractive.
Let
and then
Therefore, the sequence is decreasing and has a lower bound of 0.
This implies that
is convergent sequence. Let
We claim that
Suppose that
and, taking
,
so that
Since
for
so that
In particular, for
But,
Applying (11), we obtain
which is a contradiction tot
being infimum of
Hence,
Now, let
and
be any point. We define a sequence
.
Given that
is a normal cone with normal constant
k, it follows that,
Hence,
is an
x-Cauchy sequence. As
is
x-complete, there exist a
with
. By
x-continuity of
T,
and by
and limit’s uniqueness
.
Now, we examine the fixed point’s uniqueness. Assume that
T has distinct fixed point
with
for
By Meir–Keeler condition, for
, there exists
such that
Applying the condition to
we have
which is a contradiction because it implies
. As a result,
T possesses a unique fixed point. □
Example 8. Let . Define and This example demonstrates that the mapping on the x-complete cone m-hemi metric space satisfies the Meir–Keeler condition with , and T possesses a unique fixed point at .
Definition 13. A function is right-continuous at a point if is defined on an interval lying to the right of δ and if The definition for left-continuous is defined similarly, with lying on the left and
Definition 14. Consider as a metric space. The mapping is referred to as the Boyd–Wong mapping if there exists a function so that
- (i)
- (ii)
- (iii)
φ is right-continuous.
Now, we prove Boyd–Wong’s fixed-point theorem in the setting of cone m-hemi metric spaces.
Theorem 5. Consider as a complete metric space and ρ a normal cone with normal constant k. A mapping represents an x-continuous self-mapping that satisfies the Boyd–Wong condition if there exists a right-continuous function such that if andfor all Then, T possesses a unique fixed point. Proof. Let and be any point. We define a sequence .
Let
be the function that satisfies Boyd–Wong map condition. So, we assume that, for all
Set
and then
Therefore, the sequence is decreasing and has a lower bound of 0.
This implies that is a convergent sequence. Let
Suppose
. Since
is right-continuous function, taking the limit of
u on both sides yields
Further,
which is contradiction to the fact that
Hence,
Now, we show that
is a Cauchy sequence. On the contrary, we suppose that
is not a Cauchy sequence. Then, there exists an
such that, for each
, we choose integer
with
So, we have
Since
is a decreasing sequence, let
be the smallest integer that is greater than
l and satisfies
. We can choose the smallest
possible, meaning that
Taking the limit as
we obtain
implying that
from above as
and we have
Taking the limit
yields
which implies that
Based on the
property, this implies that
which is a contradiction. Thus, the sequence
is Cauchy. As
is
x-complete, there exist a
with
. By
x-continuity of
T,
and by
and limit’s uniqueness
.
Now, we examine the fixed point’s uniqueness. Assume that
T has distinct fixed point
with
for
. By using (
12), we obtain
which contradicts
. As a result,
T possesses a unique fixed point. □
Example 9. Consider to be the algebra of all the u-square real matrices. Let . Then, represents a normal cone, where the normal constant is Let define , and , We choose , which satisfies for The fixed point is the zero matrix