Abstract
The aim of this research article is to introduce generalized rational contractions in the context of complex-valued metric spaces and to establish novel common fixed-point theorems. Our findings generalize several well-known fixed-point theorems and contribute to the advancement of fixed-point theory. A non-trivial example is provided to demonstrate the efficacy of the obtained results. Additionally, we demonstrate the practical significance of our findings through a homotopy result.
Keywords:
common fixed point; complex-valued metric spaces; generalized rational contractions; set-valued mappings; homotopy MSC:
47H10; 54H25
1. Introduction
Fixed-point theory is a fundamental area of mathematical analysis that deals with the existence and properties of points that remain invariant under certain mappings. The concept of a fixed point (FP), where a function maps a point to itself, has profound implications in various mathematical fields and real-world applications. In this theory, the study of metric spaces (MSs) has been fundamental, providing crucial applications across various scientific disciplines such as mathematics, computer science, physics, chemistry, and biology. The widespread utility of MSs has led to numerous extensions and generalizations by researchers. Azam et al. [1] broadened the scope of metric spaces by replacing the real-valued range with complex numbers, thereby introducing the concept of complex-valued metric spaces (CVMSs). They demonstrated common FPs for two single-valued mappings under generalized contractions involving specific rational expressions. Subsequently, Rouzkard et al. [2] further developed Azam et al.’s [1] results by incorporating a rational term into the contraction conditions. Klin-eam et al. [3] gave generalized contractive-type conditions and presented some theorems that extend previous results in this area. Subsequently, Bhatt et al. [4] presented another extension of Banach’s fixed-point theorem and established common FPs of mappings satisfying the rational inequality in the context of CVMSs. Thereafter, Ahmad et al. [5] introduced the generalized Housdorff distance function in the background of CVMSs and proved common FP theorems for set-valued mappings. They established FP results for Banach and Kannan’s contractive conditions involving rational expressions given by Fisher. Afterwards, Azam et al. [6] proved common FP theorems for Chatterjea’s contractive conditions along with the rational inequality. Humaira et al. [7] obtained FP results for -fuzzy mappings in the scope of CVMSs and investigated the homotopy problem as applications of their leading theorem. Wangwe et al. [8] established FP theorems for extended interpolative Kanann–Ćirić–Reich–Rus non-self mappings within the framework of hyperbolic CVMSs. Later on, FP results involving -distances were presented by Khuangsatung et al. [9] in the setting of CVMSs. The work of Sengar [10] focused on common FP theorems for implicit relations in the context of CVMSs. Additional details and related work can be found in [11,12,13,14].
In this research article, we introduce generalized rational contractions in the setting of CVMSs and obtain some new common FP results. By our main theorem, we derive some famous results of the literature including the leading results of Azam et al. [1], Rouzkard et al. [2], Klin-eam et al. [3], Bhatt et al. [4], Ahmad et al. [5], and Azam et al. [6]. To illustrate the novelty of our primary theorem, we provide a concrete example. Moreover, we demonstrate the significance of our findings by presenting a homotopy result.
2. Preliminaries
In this section, we establish the foundational concepts and notation that will be utilized throughout this paper. Consistent with Azam et al. [1], and denote the real and imaginary components of the complex number , respectively. Let us define a partial order on the set as described below:
for . Consequently,
provided that at least one of the following criteria is met:
To be precise, we will use when and any of the conditions (i), (ii), and (iii) hold, and we will use when only condition (iii) is met.
Definition 1.
Let and be a function such that
- 1.
- and ⇔;
- 2.
- ;
- 3.
- ;
for all . Then, the couple is identified as a CVMS.
A point is an interior point of a set if there exists a positive complex number r such that
Similarly, a point is said to be the limit point of a set if for every positive complex number r, the open ball contains at least one point of E other than itself. A set E is open provided that each of its points is an interior point. A subset M of is closed whenever all of its limit points are elements of Also, a set E is bounded if it is contained within a ball of finite radius. The collection of open balls forms a sub-basis for a topology on We represent this complex topology as Importantly, is a Hausdorff topology on
According to Ahmad et al. [5], the generalized Hausdorff distance function in a CVMS is defined as follows.
Let for and
for and
For , we denote
where , , and are non-empty, closed, and bounded subsets of the CVMS , respectively.
Remark 1.
If in Definition 1, we take that is, then the CVMS is reduced to an MS. Additionally, for represents the Hausdorff distance derived from
Let be a set-valued mapping. For and , we define
Thus, for ,
Definition 2
([5]). A set-valued function is said to possess the greatest lower bound (glb) property on Θ if the greatest lower bound of exists within the complex numbers for all . We symbolize this glb by i.e.,
In the upcoming results, the set-valued mappings and ℶ satisfy the glb property.
Ahmad et al. [5] proved the following common FP theorem for set-valued mappings satisfying a Banach-type contraction, incorporating a rational expression in the setting of CVMSs.
Theorem 1.
Let . Assume that there exist non-negative real numbers for with such that
for all Then, and ℶ have a common FP.
They [5] also established a common FP result for a Kannan-type contraction.
Theorem 2.
Let . Assume that there exist non-negative real numbers for with such that
for all Then, and ℶ have a common FP.
Theorem 3.
Let . Assume that there exist non-negative real numbers for with such that
for all Then, and ℶ have a common FP.
The following lemmas are necessary:
Lemma 1
([1]). A sequence in the CVMS Θ converges to a point if and only if as
Lemma 2
([1]). A sequence in the CVMS Θ is Cauchy if and only if as
3. Main Results
In this section, we prove novel FP theorems for set-valued mappings that fulfill generalized contractive conditions within the framework of a complete CVMS.
Theorem 4.
Let be a complete CVMS and let be set-valued mappings satisfying the glb property. Assume the existence of non-negative real numbers for such that
and
for all Then, and ℶ have a common FP.
Proof.
Choose an arbitrary point in the set Subsequently, select a point that is an element of i.e., From (1), we have
By definition of “⋏”, we have
which implies
This yields
for all Now, since we have
that is,
So, there exists some such that
That is,
Leveraging the glb property inherent to and we obtain
which implies that
Now, since we have
According to the triangle inequality of the CVMS, we have
which implies
Similarly, according to (1), we have
By definition of “⋏”, we have
which implies
This yields
for all Now, since we have
that is,
So, there exists some such that
that is,
Leveraging the glb property inherent to both and ℶ, we obtain
which implies that
Now, since we have
According to the triangle inequality of the CVMS, we have
which implies
Let ; then, from (2) and (3), we have
Employing an inductive approach, a sequence can be constructed within where , , and
for all Now, for we obtain
Since in the numerator, we have Consequently,
Accordingly,
as because Consequently, is Cauchy within Given the completeness of , there exists in such that as To demonstrate that and we refer to Equation (1) and observe
By definition of “⋏”, we have
that is,
This implies that
for all Since we have
By definition of “⋏”, we have
There exists some such that
that is,
Leveraging the glb property inherent to both and ℶ, we obtain
Since
using (6), we obtain
that is,
Taking the limit as we obtain Since Thus, by Lemma 2, we have as Since is closed, Likewise, it can be deduced that Consequently, and have a common FP. □
Notation 1.
For the remainder of this work, we will consider a complete CVMS and assume that the set-valued mappings possess the glb property.
Corollary 1.
Let . Assume that there exist non-negative real numbers for such that
and
for all Then, has an FP.
Proof.
Set in Theorem 4. □
Corollary 2.
Let . Assume the existence of non-negative real numbers for such that
and
for all Then, and ℶ have a common FP.
Proof.
Take in Theorem 4. □
Corollary 3.
Let . Assume the existence of non-negative real numbers for such that
and
for all Then, and ℶ have a common FP.
Proof.
Take in Theorem 4. □
Corollary 4.
Let . Assume the existence of non-negative real numbers for such that
and
for all Then, and ℶ have a common FP.
Proof.
Set in Theorem 4. □
A Hardy–Roger-type theorem for set-valued mappings can be deduced by our prime theorem in such manner.
Corollary 5.
Let . Assume the existence of non-negative real numbers for such that and
for all Then, and ℶ have a common FP.
Proof.
Put in Theorem 4. □
We now present a Reich-type FP theorem for set-valued mappings in the context of CVMSs.
Corollary 6.
Let . Assume the existence of non-negative real numbers and such that and
for all Then, and ℶ have a common FP.
Proof.
Substitute in Theorem 4. □
Here, we state a Banach-type FP theorem for set-valued mappings in the CVMS as the corollary of our prime result.
Corollary 7.
Let . Assume the existence of non-negative real number ς such that
for all Then, and ℶ have a common FP.
Proof.
Take and in Theorem 4. □
A Kannan-type theorem for set-valued mappings in the setting of a CVMS can be deduced in such a way.
Corollary 8.
Let . Assume the existence of non-negative real number ς such that
for all Then, and ℶ have a common FP.
Proof.
Set and in Theorem 4. □
Now, we derive a result which is a Chaterrjea-type theorem for set-valued mappings in the background of a CVMS.
Corollary 9.
Let . Assume the existence of non-negative real number ς such that
for all Then, have a common FP.
Proof.
Set and in Theorem 4. □
Our main Theorem 4 can be specialized to yield a result that improves upon the main theorem of Ahmad et al. [5].
Corollary 10.
Let . Assume the existence of non-negative real numbers for such that and
for all Then, have a common FP.
Proof.
Take in Theorem 4. □
Building upon our primary theorem, Theorem 4, we also establish a result that generalizes the key finding of Ahmad et al. [5].
Corollary 11.
Let . Assume the existence of non-negative real numbers for such that and
for all Then, have a common FP.
Proof.
Take in Theorem 4. □
As a corollary to our main theorem, Theorem 4, we present a result that encompasses the primary theorem of Azam et al. [6].
Corollary 12.
Let . Assume the existence of non-negative real numbers for such that and
for all Then, have a common FP.
Proof.
Take in Theorem 4. □
Example 1.
Let , and let us define by
Then, is a CVMS. Consider the mappings , defined by
The contractive condition in the main theorem becomes vacuous when both and τ equal zero. Henceforth, we assume without a loss of generality that and τ are nonzero and is strictly less than τ. Consequently,
and
Let us consider
It is apparent that for any selection of (where ) and , we observe
Thus,
Consequently, all conditions of our primary theorem, Theorem 4, are fulfilled. Thus, 0 is a common FP of mappings and ℶ.
Theorem 5.
Let . Assume that there exist , and non-negative real numbers for such that
and
for all and
where . Then, and ℶ have a common FP in .
Proof.
Consider an arbitrary point in the set . Based on the results established in (8), it can be readily shown that
Thus, we have . The proof of Theorem 4 demonstrates that
and
Let ; then, from (10) and (11), we have
and
Now, from (9) and (12), we obtain
Note that
Thus, we have Now, by (8), (13), and (14), we have that
So, By iteratively applying this process, we can generate a sequence within the closed ball satisfying , ,
and
for and . Now, by (15) and (16), we have
for Employing a technique analogous to the proof of Theorem 4, we establish the existence of a common FP for mappings and ℶ in . □
Corollary 13.
Let . Assume that there exist , and non-negative real numbers for such that
and
for all and
where . Then, has an FP in .
4. Application
Homotopy theory, a cornerstone of algebraic topology, delves into the study of topological spaces up to homotopy equivalence. In recent years, this theory has revealed profound connections to various mathematical fields. Consequently, it has given rise to numerous FP theorems for homotopic mappings [15,16]. In this section, we leverage our findings to establish FP theorems for homotopic mappings.
Theorem 6.
Consider a complete CVMS and an open subset U of Θ and let be set-valued mapping such that both and ℶ possess the glb property. Assume that and such that
(Hom1): for all and ;
(Hom2): fulfilling
and
where
(Hom3): there exists a continuous increasing function such that
for all and , where Then, attains an FP if attains an FP.
Proof.
Assume that attains an FP so By the condition (Hom1), We define the following set:
Clearly, A partial order ≾ on is defined as follows:
Consider a totally ordered subset of and Consider in , provided that and as Then, for any with we have
as , which yields that is Cauchy. Since is complete, we can find such that From (Hom1), we choose in such a way that
for all , which implies
since Consequently, there exists an element such that
Utilizing the glb characteristic of , it follows that
that is,
which yields that
Since , we have
which implies
Note that
for all . Letting we obtain
which is possible only if converges to an element within consequently implying that which yields Therefore, ∀ signifying that is an upper bound of . Consequently, by Zorn’s Lemma, possesses a maximal element
Now, we propose . Suppose that . We choose and , where and . Using (Hom3), we have
for all . So, there exists such that and so
which implies that
Furthermore, by applying condition (Hom2), it follows that fulfills all hypotheses of Corollary 13 for each . Consequently, for every in , there exists an element within satisfying belonging to This implies that the pair is an element of . Given that
this yields , which leads to a contradiction implying that must equal Consequently, attains an FP.
On the other hand, if attains an FP, a similar argument establishes the existence of an FP for . □
5. Conclusions
In the present research article, we strengthened the idea of CVMSs pioneered by Azam et al. [1] and established the common FP theorems for set-valued mappings. Our findings extended upon prominent outcomes in the literature including the leading findings of Azam et al. [1], Rouzkard et al. [2], Klin-eam et al. [3], Bhatt et al. [4], Ahmad et al. [5], and Azam et al. [6]. To underscore the groundbreaking character of our principal theorem, a concrete example has been provided. Furthermore, the practical utility of our results is demonstrated through the development of a homotopy result.
Potential avenues for future research include extending FP and common FP theorems to fuzzy and L-fuzzy mappings in the background of these generalized contractions. Likewise, the exploration of differential and integral inclusions in CVMSs is warranted. The results presented herein may inspire further investigations and refinements by other researchers to address a wider range of applications.
Author Contributions
Conceptualization, A.E.S. and J.A.; methodology, J.A.; software, A.E.S.; validation, A.E.S.; formal analysis, A.E.S.; investigation, J.A.; resources, A.E.S.; data curation, A.E.S.; writing—original draft preparation, J.A.; writing—review and editing, A.E.S.; visualization, J.A.; supervision, A.E.S.; project administration, J.A.; funding acquisition, A.E.S. All authors have read and agreed to the published version of the manuscript.
Funding
This research received no external funding.
Data Availability Statement
The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding author.
Conflicts of Interest
The authors declare no conflicts of interest.
References
- Azam, A.; Fisher, B.; Khan, M. Common fixed point theorems in complex valued metric spaces. Num. Funct. Anal. Optimiz. 2011, 32, 243–253. [Google Scholar] [CrossRef]
- Rouzkard, F.; Imdad, M. Some common fixed point theorems on complex valued metric spaces. Comp. Math. Appl. 2012, 64, 1866–1874. [Google Scholar] [CrossRef]
- Klin-eam, C.; Suanoom, C. Some common fixed point theorems for generalized contractive type mappings on complex valued metric spaces. Abstr. Appl. Anal. 2013, 2013, 604215. [Google Scholar] [CrossRef]
- Bhatt, S.; Chaukiyal, S.; Dimri, R.C. Common fixed point of mappings satisfying rational inequality in complex valued metric space. Int. J. Pure Appl. Math. 2011, 73, 159–164. [Google Scholar]
- Ahmad, J.; Klin-eam, C.; Azam, A. Common fixed points for multivalued mappings in complex valued metric spaces with applications. Abstr. Appl. Anal. 2013, 2013, 854965. [Google Scholar] [CrossRef]
- Azam, A.; Ahmad, J.; Kumam, P. Common fixed point theorems for multi-valued mappings in complex-valued metric spaces. J. Inequalities Appl. 2013, 2013, 578. [Google Scholar] [CrossRef]
- Humaira, M.; Sarwar, G.; Kishore, N.V. Fuzzy fixed point results for φ contractive mapping with applications. Complexity 2018, 2018, 5303815. [Google Scholar] [CrossRef]
- Wangwe, L.; Rathour, L.; Mishra, L.N.; Mishra, V.N. Fixed point theorems for extended interpolative Kanann-Ćirić-Reich-Rus non-self type mapping in hyperbolic complex-valued metric space. Adv. Stud. Euro-Tbil. Math. J. 2024, 17, 1–21. [Google Scholar] [CrossRef]
- Khuangsatung, L.; Gebrie, A.G.; Suanoom, C. Some new results on fixed points for ϖ-distances in complex valued metric spaces. Sci. Technol. Asia 2024, 29, 173–182. [Google Scholar]
- Sengar, P. Common fixed point theorems in complex valued metric space using implicit relation. Int. Res. J. Math. Eng. 2024, 11, 11–19. [Google Scholar]
- Majid, N.A.; Jumaili, A.M.A.; Ng, Z.C.; Lee, S.K. New results of fixed point theorems and their applications in complete complex -metric spaces. J. Funct. Spaces 2024, 2024, 5532624. [Google Scholar] [CrossRef]
- Shammaky, A.E.; Ahmad, J. Generalization of fixed point results in complex-valued bipolar metric space with applications. Axioms 2024, 13, 550. [Google Scholar] [CrossRef]
- Sintunavarat, W.; Kumam, P. Generalized common fixed point theorems in complex valued metric spaces and applications. J. Inequal. Appl. 2012, 2012, 84. [Google Scholar] [CrossRef]
- Sitthikul, K.; Saejung, S. Some fixed point theorems in complex valued metric spaces. Fixed Point Theory Appl. 2012, 2012, 189. [Google Scholar] [CrossRef]
- Vetro, C.; Vetro, F. A homotopy fixed point theorem in 0-complete partial metric space. Filomat 2015, 29, 2037–2048. [Google Scholar] [CrossRef]
- Agarwal, R.; Dshalalow, J.; O’Regan, D. Fixed point and homotopy results for generalized contractive maps of Reich type. Appl. Anal. 2003, 82, 329–350. [Google Scholar] [CrossRef]
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