The concept of contraction mappings plays a significant role in mathematics, particularly in the study of fixed points and the existence of solutions for various equations. In this study, we described two types of enriched contractions: enriched F-contraction and enriched F′-contraction associated with u-fold averaged mapping, which are involved with Kirk's iterative technique with order u. The contractions extracted from this paper generalized and unified many previously common super contractions. Furthermore, u-fold averaged mappings can be seen as a more general form of both averaged mappings and double averaged mappings. Moreover, we demonstrated that the u-fold averaged mapping with enriched contractions has a unique fixed point. Our work examined the necessary conditions for the u-fold averaged mapping and weak enriched contractions to have equal sets of fixed points. Additionally, we illustrated that an appropriate Kirk's iterative algorithm can effectively approximate a fixed point of a u-fold averaged mapping as well as the two enriched contractions. Also, we delved into the well-posedness, limit shadowing property, and Ulam-Hyers stability of the u-fold averaged mapping. Furthermore, we established necessary conditions that guaranteed the periodic point property for each of the illustrated strengthened contractions. To underscore the generality of our findings, we presented several examples that aligned with comparable results found in the existing literature.
Citation: Kottakkaran Sooppy Nisar, Hasanen A. Hammad, Mohamed Elmursi. A new class of hybrid contractions with higher-order iterative Kirk's method for reckoning fixed points[J]. AIMS Mathematics, 2024, 9(8): 20413-20440. doi: 10.3934/math.2024993
[1] | Kottakkaran Sooppy Nisar, Hasanen A. Hammad, Mohamed Elmursi . Corrigendum to "A new class of hybrid contractions with higher-order iterative Kirk's method for reckoning fixed points". AIMS Mathematics, 2024, 9(9): 25934-25935. doi: 10.3934/math.20241266 |
[2] | Noor Muhammad, Ali Asghar, Samina Irum, Ali Akgül, E. M. Khalil, Mustafa Inc . Approximation of fixed point of generalized non-expansive mapping via new faster iterative scheme in metric domain. AIMS Mathematics, 2023, 8(2): 2856-2870. doi: 10.3934/math.2023149 |
[3] | Dong Ji, Yao Yu, Chaobo Li . Fixed point and endpoint theorems of multivalued mappings in convex b-metric spaces with an application. AIMS Mathematics, 2024, 9(3): 7589-7609. doi: 10.3934/math.2024368 |
[4] | Aftab Hussain . Fractional convex type contraction with solution of fractional differential equation. AIMS Mathematics, 2020, 5(5): 5364-5380. doi: 10.3934/math.2020344 |
[5] | Muhammad Rafique, Talat Nazir, Mujahid Abbas . Common fixed points of fuzzy set-valued contractive mappings on metric spaces with a directed graph. AIMS Mathematics, 2022, 7(2): 2195-2219. doi: 10.3934/math.2022125 |
[6] | Abdelkader Belhenniche, Amelia Bucur, Liliana Guran, Adrian Nicolae Branga . Using computational techniques of fixed point theory for studying the stationary infinite horizon problem from the financial field. AIMS Mathematics, 2024, 9(1): 2369-2388. doi: 10.3934/math.2024117 |
[7] | Kifayat Ullah, Junaid Ahmad, Hasanen A. Hammad, Reny George . Iterative schemes for numerical reckoning of fixed points of new nonexpansive mappings with an application. AIMS Mathematics, 2023, 8(5): 10711-10727. doi: 10.3934/math.2023543 |
[8] | Junaid Ahmad, Kifayat Ullah, Hasanen A. Hammad, Reny George . On fixed-point approximations for a class of nonlinear mappings based on the JK iterative scheme with application. AIMS Mathematics, 2023, 8(6): 13663-13679. doi: 10.3934/math.2023694 |
[9] | Wasfi Shatanawi, Taqi A. M. Shatnawi . New fixed point results in controlled metric type spaces based on new contractive conditions. AIMS Mathematics, 2023, 8(4): 9314-9330. doi: 10.3934/math.2023468 |
[10] | Qing Yang, Chuanzhi Bai . Fixed point theorem for orthogonal contraction of Hardy-Rogers-type mapping on O-complete metric spaces. AIMS Mathematics, 2020, 5(6): 5734-5742. doi: 10.3934/math.2020368 |
The concept of contraction mappings plays a significant role in mathematics, particularly in the study of fixed points and the existence of solutions for various equations. In this study, we described two types of enriched contractions: enriched F-contraction and enriched F′-contraction associated with u-fold averaged mapping, which are involved with Kirk's iterative technique with order u. The contractions extracted from this paper generalized and unified many previously common super contractions. Furthermore, u-fold averaged mappings can be seen as a more general form of both averaged mappings and double averaged mappings. Moreover, we demonstrated that the u-fold averaged mapping with enriched contractions has a unique fixed point. Our work examined the necessary conditions for the u-fold averaged mapping and weak enriched contractions to have equal sets of fixed points. Additionally, we illustrated that an appropriate Kirk's iterative algorithm can effectively approximate a fixed point of a u-fold averaged mapping as well as the two enriched contractions. Also, we delved into the well-posedness, limit shadowing property, and Ulam-Hyers stability of the u-fold averaged mapping. Furthermore, we established necessary conditions that guaranteed the periodic point property for each of the illustrated strengthened contractions. To underscore the generality of our findings, we presented several examples that aligned with comparable results found in the existing literature.
NEM→non-expansive mapping | FP→fixed point |
ECM→enriched contraction mapping | MS→metric space |
EKC→enriched Kannan contraction | BS→Banach space |
ECC→enriched Chatterjea contraction | BC→Banach contraction |
ECRRC→enriched Ćirić-Reich-Rus-contraction | PO→Picard operator |
EIKC→enriched interpolative Kannan-contraction | KI→Kirk's iteration |
EICRRC→enriched interpolative Ćirić -Reich-Rus-contraction | AM→averaged mapping |
KIS→Krasnoselskii iterative scheme | NS→normed space |
HEF-C→hybrid enriched F-contraction | UH→ Ulam-Hyers |
HEF′-C→hybrid enriched F′-contraction | PPP→periodic point property |
One of the most helpful methods for studying nonlinear equations, whether they be differential, integral, or algebraic equations, is the contraction mapping principle. The idea is based on the fixed point (FP) theorem, which states that every contraction mapping of a complete metric space (MS) to itself will have a single FP. This FP can be found as the limit of an iteration scheme made up of repeated images under the mapping of any arbitrary beginning point in the space. Since it is a constructive FP theorem, the FP can be computed numerically using it.
Assume that Θ is a nonempty set of a Banach space (BS) Ω. A mapping ℑ:Θ→Θ is called a non-expansive mapping (NEM), if for all ω,θ∈Θ, the inequality below holds:
‖ℑω−ℑθ‖≤‖ω−θ‖. |
The FP of ℑ is an element ω∗∈Θ, which satisfies an operator equation ℑω∗=ω∗. The set of FPs of the mapping ℑ is denoted by Fix(ℑ). Let ω0∈Ω be an arbitrary point, and the forward orbit of ω0 is denoted by O(ℑ,ω0,∞), and is described as the set {ω0,ℑm(ω0):m≥1}. The set {ω,ℑ(ω),⋯,ℑm(ω)} will be described as O{ω,ℑ,m}. The mth iterate of the mapping ℑ is described as ℑm=ℑm−1∘ℑ,m≥1,ℑ0=I (where I is the identity mapping on Ω).
If Fix(ℑ)={ω∗} and O(ℑ,ω0,∞)→ω∗ as m→∞, then the mapping ℑ is called a Picard operator (PO). Moreover, if there is a constant ρ∈[0,1) such that
d(ℑω,ℑθ)≤ρd(ω,θ), |
for all ω and θ belonging to a complete MS Ω, then the mapping ℑ:Ω→Ω is known as a Banach contraction (BC) mapping. Clearly, the BC mapping converts to NEM if ρ=1. As the limiting situation of BC mappings, one can consider the NEMs. A BC mapping's mth iterates are referred to as Picard's iterates. Any BC mapping constructed on a complete MS (Ω,d) is a PO, as per the BC principle [1]. Furthermore, Picard's iterates can approximate the FP of the mapping ℑ for each ω0∈Ω, but an NEM ℑ does not produce a forward orbit that converges to ℑ's FP. In other words, if ℑ:Θ→Θ is an NEM, then ℑ may not have an FP, may have more than one FP, or may even have a unique FP; in contrast, the forward orbit created by a NEM will not converge to its FP. Therefore, other approximation methods are required in order to estimate the FPs of NEMs. Additionally, a complex geometric structure of the underlying spaces is necessary for the FPs of NEMs to exist. Due to these factors, one of the main and most active subfields of nonlinear analytic research is the study of NEMs.
Banach fixed-point theorem provides a powerful tool for establishing the existence and uniqueness of fixed points in metric spaces, which has implications in optimization, inverse problems, and other mathematical contexts, for more details, see [2,3,4,5,6,7,8,9]
Exact averaged iterations of the form ωm+1=g(ωm,ℑωm+1),m≥1 have been used by numerous writers. One well-known method is to create an averaged mapping (AM): If ℑϑ=(1−ϑ)I+ϑℑ, then an operator ℑϑ associated with ℑ and identity mapping I is an AM for a given operator ℑ on Ω and ϑ∈(0,1). This concept was first used in [10], when it was demonstrated that the forward orbit caused by ℑϑ converges to an FP of ℑ under specific circumstances. The initial noteworthy outcome in this regard was acquired by Krasnoselskii [11]. In the event that Θ represents a closed convex subset of a uniformly convex BS and ℑ is an NEM on Θ into a compact subset of Θ, then the forward orbit of any ω in Θ for ϑ=0.5 converges to an FP of ℑ. Schaefer [12] demonstrated the aforementioned outcomes for an arbitrary ϑ∈(0,1). The same result was then presented by Edelstein [13] in the context of a strictly convex BS, which is a broader concept than a uniformly convex BS. It is obvious that Picard's iteration method is generalized by Krasnoselskii's iteration.
In 1971, Kirk [14] created a significant iteration technique called Kirk's iteration (KI) scheme, which is defined by
ωm=κ0ωm−1+κ1ℑωm−1+κ2ℑ2ωm−1+⋯+κuℑuωm−1, |
where ω0∈Θ,κ0>0, and for j=1,2,⋯u,κj≥0 with ∑uj=1κj=1.
KI method, in fact, is a forward orbit of the mapping ℧:Θ→Θ [14] described by
℧=κ0I+κ1ℑ+κ2ℑ2+⋯+κuℑu, | (1.1) |
where κ0>0, and for j=1,2,⋯u,κj≥0 with ∑uj=1κj=1. Undoubtedly, the mapping ℧ is a generalization of the AM ℑϑ.
Kirk demonstrated that, under certain appropriate conditions, the set of FPs of the mapping ℧ corresponds with Fix(ℑ), and that the KI method converges to the FP of ℑ:
Theorem 1.1. [14] Assume that Θ is a convex subset of a BS Ω, and ℑ:Ω→Ω is a NEM. If ℧:Ω→Ω is a mapping described as in (1.1), then ℧(ω)=ω if ℑ(ω)=ω.
The concept of enriched contractive mappings (ECMs) was recently introduced by Berinde and Păcurar [15]. Let Ω be a BS, and the mapping ℑ:Ω→Ω is said to be ECM if there are τ≥0 and σ∈[0,τ+1) in order that
‖τ(ω−θ)+ℑω−ℑθ‖≤σ‖ω−θ‖, for all ω,θ∈Ω. |
They established the existence of an FP of an ECM, which may be roughly represented using a suitable Krasnoselskii iterative scheme (KIS). To be more precise, the sequence {ℑmϑω0} can approximate the FP of ℑ, which is also an FP of the AM ℑϑ with ϑ∈(0,1] for each ω0∈Ω.
Theorem 1.2. [15] Assume that ℑ:Ω→Ω is an ECM defined on a BS Ω. Then |Fix(ℑ)|=1, and there is ϑ∈(0,1] such that the KIS {ωm} iterated by
ωm=(1−ϑ)ωm−1+ϑℑωm−1, for all ω0∈Ω, and m≥0 |
converges to a unique FP of ℑ.
It is important to note that only the displacements ‖ℑω−ℑθ‖ and ‖ω−θ‖ are included in the enriched contraction mapping that Berinde and Păcurar [15] presented. Nonetheless, for every two distinct points ω,θ∈Ω, there are four more displacements linked to a self-mapping ℑ, denoted by ‖ω−ℑω‖, ‖θ−ℑθ‖, ‖ω−ℑθ‖, and ‖θ−ℑω‖. More than one displacement is involved in a number of well-known contraction mappings. For more details, see [16,17,18,19,20,21,22,23,24,25,26,27]. The authors in [28] have proposed the concept of weak ECMs, which are an extension of AMs known as double AMs. Assume that κ1>0,κ2≥0 with κ1+κ2=1 and ℑ:Ω→Ω is a mapping defined on a BS Ω. Double AM ℑκ1,κ2 is a mapping related to I, ℑ, and ℑ2 and is described as
ℑκ1,κ2=(1−κ1−κ2)I+κ1ℑ+κ2ℑ2. |
Clearly, ℑκ1,κ2 is more general than ℑϑ(ℑϑ=ℑκ1,0). Additionally, the mapping ℧ in [14] of order u=2 is a specific instance of the double AM ℑκ1,κ2. A given mapping ℑ:Ω→Ω on a BS Ω is said to be a weak ECM if there are τ,˜τ≥0 and ℓ∈[0,τ+˜τ+1) such that
‖τ(ω−θ)+ℑω−ℑθ+˜τ(ℑ2ω−ℑ2θ)‖≤ℓ‖ω−θ‖, for all ω,θ∈Ω. |
According to the findings of [28], for every self-mapping ℑ on a closed convex subset of a BS that satisfies the weak ECM, there exist κ1>0,κ2≥0 with κ1+κ2∈(0,1] such that ℑκ1,κ2 has a unique FP that can be approximated by a suitable KIS. We make reference to the next paragraph. Their theorem was formulated as follows:
Theorem 1.3. [28] Assume that (Ω,‖.‖) is a BS, Θ is a closed convex subset of Ω and ℑ:Θ→Θ is a weak ECM. Then, there are κ1>0,κ2≥0 with κ1+κ2∈(0,1] such that the assertions below hold
(1) |Fix(ℑκ1,κ2)|=1;
(2) For any ω0∈Θ, the iterated sequence {ωm}⊂Θ generated by
ωm=(1−κ1−κ2)ωm−1+κ1ℑωm−1+κ2ℑ2ωm−1, for m∈N |
converges to a unique FP of ℑκ1,κ2.
KIS of order u, which is produced by a generalized ECM, appears to be a good way to unify the FP results that have been described. This unification has two components: KIS of order more than two is examined, and ECMs are generalized such that the many ECMs that currently exist are inferred as specific examples.
So, in this article, two types of enriched contractions related to KIS with order u are described in this paper: hybrid enriched F-contraction and hybrid enriched F′-contraction connected with u-fold AM. The contractions taken from this paper unify and generalize a lot of super contractions that were previously widespread. Additionally, one may consider u-fold ANs to be a more universal version of double and AMs. Furthermore, we prove the existence of a unique FP for the u-fold AM with enriched contractions. We investigate what requirements must be met in order for the weak hybrid ECMs and the u-fold AM to have identical sets of FPs. In addition, we demonstrate how a suitable KIS can efficiently approximate both the FP and the average of a u-fold mapping.
We begin by introducing two mapping families. Assume that F is the class of all mappings ℏ:R4+→R+ that meet the requirements listed below:
(ℏ1) In every argument, ℏ is continuous;
(ℏ2) there is ζ∈[0,1) such that if ϰ<ℏ(ϱ,ϰ,ϱ,ϱ+ϰ) or ϰ<ℏ(ϱ,ϰ,ϱ,ϰ) or ϰ<ℏ(ϰ,ϱ,ϱ,ϰ) or ϰ<ℏ(ϰ,ϱ,ϱ,ϱ), then for all ϰ,ϱ∈R+,ϰ≤ζϱ;
(ℏ3)ϑℏ(ϰ,ϱ,ξ,υ)≤ℏ(ϑϰ,ϑϱ,ϑξ,ϑυ), for ϑ>0 and for all ϰ,ϱ,ξ,υ∈R+;
(ℏ4) if υ≤υ′, then ℏ(ϰ,ϱ,ξ,υ)≤ℏ(ϰ,ϱ,ξ,υ′) for all ϰ,ϱ,ξ,υ,υ′∈R+.
To demonstrate that the family F is nonempty, we now provide some examples.
Example 2.1. It is simple to confirm that the mappings shown below are a part of class F:
(i) ℏ(ϰ,ϱ,ξ,υ)=κmax{ϰ+ϱ,ϱ+ξ,ξ+υ,ϰ+υ}, where κ∈[0,12);
(ii) ℏ(ϰ,ϱ,ξ,υ)=maxκ{ϰ,ϱ,ξ,υ}, where κ∈[0,1);
(iii) ℏ(ϰ,ϱ,ξ,υ)=maxκ{ϱ,ξ,υ}, where κ∈[0,1);
(iv) ℏ(ϰ,ϱ,ξ,υ)=κϰ, where κ∈[0,1);
(v) ℏ(ϰ,ϱ,ξ,υ)=κ(ϰ+ϱ), where κ∈[0,12);
(vi) ℏ(ϰ,ϱ,ξ,υ)=κ(ξ+υ), where κ∈[0,12);
(vii) ℏ(ϰ,ϱ,ξ,υ)=ξκυ1−κ, where κ∈(0,1);
(viii) ℏ(ϰ,ϱ,ξ,υ)=ϰκ1ϱκ2ξκ3υ1−κ1−κ2−κ3, where κ1,κ2,κ3∈(0,1) with κ1+κ2+κ3<1;
(ix) ℏ(ϰ,ϱ,ξ,υ)=κ1ϰ+κ2ϱ+κ3ξ+κ4υ, where κ1,κ2,κ3,κ4∈[0,1) with κ1+κ2+κ3+κ4=1.
Assume that F′ is the class of all mappings ℏ:R4+→R+ that meet the requirements listed below:
(ℏ′1) In every argument, ℏ is continuous;
(ℏ′2) there is ζ∈[0,1) such that if ϰ<ℏ(ϱ,ϱ+ϰ,0,ϱ+ϰ), or ϰ<ℏ(ϱ,ϰ,ϰ,ϰ), or ϰ<ℏ(ϱ,0,0,ϰ+ϱ), or ϰ<ℏ(ϰ,ϱ,ϱ,ϱ), then for all ϰ,ϱ∈R+,ϰ≤ζϱ;
(ℏ′3)ϑℏ(ϰ,ϱ,ξ,υ)≤ℏ(ϑϰ,ϑϱ,ϑξ,ϑυ), for ϑ>0 and for all ϰ,ϱ,ξ,υ∈R+;
(ℏ′4) if υ≤υ′, then ℏ(ϰ,ϱ,ξ,υ)≤ℏ(ϰ,ϱ,ξ,υ′) for all ϰ,ϱ,ξ,υ,υ′∈R+;
(ℏ′5) if ϰ≤ℏ(ϰ,ϰ,ϰ,ϰ), then ϰ=0.
To illustrate that the family F′ is nonempty, we consider the following examples:
Example 2.2. It is simple to confirm that the mappings shown below are a part of the family F′:
(i) ℏ(ϰ,ϱ,ξ,υ)=κmax{ϰ+ϱ,ϱ+ξ,ξ+υ,ϰ+υ}, where κ∈[0,12);
(ii) ℏ(ϰ,ϱ,ξ,υ)=κϰ, where κ∈[0,1);
(iii) ℏ(ϰ,ϱ,ξ,υ)=κ(ϱ+ξ), where κ∈[0,12);
(iv) ℏ(ϰ,ϱ,ξ,υ)=κ(ξ+υ), where κ∈[0,12);
(vi) ℏ(ϰ,ϱ,ξ,υ)=κ(ϰ+ϱ+ξ+υ), where κ∈[0,13);
(vii) ℏ(ϰ,ϱ,ξ,υ)=κ(ϰϱξυ)14, where κ∈[0,1);
(viii) ℏ(ϰ,ϱ,ξ,υ)=κ√ϰϱ, where κ∈[0,13).
Here, we provide the u-fold AM using the mapping ℧ [14].
Definition 2.1. Let Ω be a BS, Θ be a nonempty subset of Ω, and ℑ:Ω→Ω is a given mapping. Describe the mapping ˆℑ:Θ→Θ associated with ℑ as
ˆℑ=(1−κ1−κ2−κ3−⋯−κu)I+κ1ℑ+κ2ℑ2+κ3ℑ3+⋯+κuℑu, |
where κj>0,∑uj=1κj∈(0,1],u≥4,u∈N. We say that the mapping ℑ′ is u-fold AM.
Now, let us provide two concepts of ECMs.
Definition 2.2. Suppose that (Ω,‖.‖) is a normed space (NS). We say that the mapping ℑ:Ω→Ω is a hybrid enriched F-contraction (HEF-C) if there is ℏ∈F in order that for all ω,θ∈Ω,bj∈(0,∞),j=1,2,⋯,u,u≥4,u∈N, we get
‖b1(ω−θ)+ℑω−ℑθ+b2(ℑ2ω−ℑ2θ)+b3(ℑ3ω−ℑ3θ)+⋯+bu(ℑuω−ℑuθ)‖≤ℏ((u∑j=1bj+1)‖ω−θ‖,‖(ω−ℑω)+b2(ω−ℑ2ω)+b3(ω−ℑ3ω)+⋯+bu(ω−ℑuω)‖,‖(θ−ℑθ)+b2(θ−ℑ2θ)+b3(θ−ℑ3θ)+⋯+bu(θ−ℑuθ)‖,‖(θ−ℑω)+b2(θ−ℑ2ω)+b3(θ−ℑ3ω)+⋯+bu(θ−ℑuω)‖). | (2.1) |
Definition 2.3. Let (Ω,‖.‖) be an NS. We say that the mapping ℑ:Ω→Ω is a hybrid enriched F′-contraction (HEF′-C) if there is ℏ∈F′ in order that for all ω,θ∈Ω,bj∈(0,∞),j=1,2,⋯,u,u≥4,u∈N, we get
‖b1(ω−θ)+ℑω−ℑθ+b2(ℑ2ω−ℑ2θ)+b3(ℑ3ω−ℑ3θ)+⋯+bu(ℑuω−ℑuθ)‖≤ℏ((u∑j=1bj+1)‖ω−θ‖,‖(u∑j=1bj+1)(θ−ω)+(ω−ℑω)+b2(ω−ℑ2ω)+b3(ω−ℑ3ω)+⋯+bu(ω−ℑuω)‖,‖(u∑j=1bj+1)(ω−θ)+(θ−ℑθ)+b2(θ−ℑ2θ)+b3(θ−ℑ3θ)+⋯+bu(θ−ℑuθ)‖,‖(θ−ℑω)+b2(θ−ℑ2ω)+b3(θ−ℑ3ω)+⋯+bu(θ−ℑuω)‖). | (2.2) |
The definitions above are supported by the following examples:
Example 2.3. Assume that Ω=R is a usual NS and ℑ:[0,∞)→[0,∞) is a given mapping described as ℑω=ω3 for ω∈[0,∞). It is clear for bj=13,j=1,2,⋯,u,u≥4,u∈N, and ℏ(ϰ,ϱ,ξ,υ)=κϰ,κ=67∈[0,1) that ℑ is an HEF-C mapping. In fact, Definition 2.2 indicates that
‖b1(ω−θ)+ℑω−ℑθ+b2(ℑ2ω−ℑ2θ)+b3(ℑ3ω−ℑ3θ)+⋯+bu(ℑuω−ℑuθ)‖=‖13(ω−θ)+(ω3−θ3)+13(ω9−θ9)+13(ω27−θ27)+⋯+13u(ω3u−θ3u)‖=‖13(ω−θ)+13(ω−θ)+127(ω−θ)+181(ω−θ)+⋯+13u+1(ω−θ)‖≤2‖ω−θ‖, |
and
ℏ((u∑j=1bj+1)‖ω−θ‖,‖(ω−ℑω)+b2(ω−ℑ2ω)+b3(ω−ℑ3ω)+⋯+bu(ω−ℑuω)‖,‖(θ−ℑθ)+b2(θ−ℑ2θ)+b3(θ−ℑ3θ)+⋯+bu(θ−ℑuθ)‖,‖(θ−ℑω)+b2(θ−ℑ2ω)+b3(θ−ℑ3ω)+⋯+bu(θ−ℑuω)‖)=κ(u∑j=1bj+1)‖ω−θ‖=67(1+u3)‖ω−θ‖≥67(1+43)‖ω−θ‖=2‖ω−θ‖. |
Hence, the inequality (2.1) holds. Therefore, ℑ is an HEF-C mapping and ℑ has a unique FP 0∈[0,∞).
Example 2.4. Assume that Ω=R is a usual NS and ℑ:[0,∞)→[0,∞) is a given mapping described as ℑω=1−ω3 for ω∈[0,∞). It is clear for bj=13j,j=1,2,3,⋯,u,u≥4,u∈N, and ℏ(ϰ,ϱ,ξ,υ)=ϰ that ℑ is an HEF-C mapping. In fact, Definition 2.2 indicates that
‖b1(ω−θ)+ℑω−ℑθ+b2(ℑ2ω−ℑ2θ)+b3(ℑ3ω−ℑ3θ)+⋯+bu(ℑuω−ℑuθ)‖=‖13(ω−θ)+13(θ−ω)+19(ω9−θ9)+127(θ27−ω27)+⋯+13u(−1)u(ω3u−θ3u)‖≤u∑j=1(13j)‖ω−θ‖, |
and
ℏ((u∑j=1bj+1)‖ω−θ‖,‖(ω−ℑω)+b2(ω−ℑ2ω)+b3(ω−ℑ3ω)+⋯+bu(ω−ℑuω)‖,‖(θ−ℑθ)+b2(θ−ℑ2θ)+b3(θ−ℑ3θ)+⋯+bu(θ−ℑuθ)‖,‖(θ−ℑω)+b2(θ−ℑ2ω)+b3(θ−ℑ3ω)+⋯+bu(θ−ℑuω)‖)=(u∑j=1bj+1)‖ω−θ‖=(1+13+132+⋯+13u)‖ω−θ‖≥(13+132+⋯+13u)‖ω−θ‖=u∑j=1(13j)‖ω−θ‖. |
Hence, the inequality (2.1) is true and ℑ is an HEF-C mapping. Here, ℑ has a unique FP 34∈[0,∞).
Example 2.5. Suppose that Ω=R is a usual NS, Λ=[−1,−13]∪[1,13]⊆Ω, and ℑ:Λ→Λ is a given mapping given by
ℑω={−ω, if ω∈[−1,−13],1−ω,if ω∈[13,1]. |
Then, for bj=1,j=1,2,3,⋯,u,u≥4,u∈N, and ℏ(ϰ,ϱ,ξ,υ)=15(ξ+υ), the mapping ℑ is an HEF′-C.
To illustrate this, without loss of the generality, we consider ω,θ∈Λ with ω≤θ. We have the following cases:
Case 1. For each ω,θ∈[−1,−13] or ω,θ∈[13,1], the Definition 2.3 implies that
‖b1(ω−θ)+ℑω−ℑθ+b2(ℑ2ω−ℑ2θ)+b3(ℑ3ω−ℑ3θ)+⋯+bu(ℑuω−ℑuθ)‖=‖(ω−θ)+(θ−ω)+(ω−θ)+(θ−ω)+⋯+(−1)u(ω−θ)‖={0,if u is odd,‖ω−θ‖,if u is even, |
and
ℏ((u∑j=1bj+1)‖ω−θ‖,‖(u∑j=1bj+1)(θ−ω)+(ω−ℑω)+b2(ω−ℑ2ω)+b3(ω−ℑ3ω)+⋯+bu(ω−ℑuω)‖,‖(u∑j=1bj+1)(ω−θ)+(θ−ℑθ)+b2(θ−ℑ2θ)+b3(θ−ℑ3θ)+⋯+bu(θ−ℑuθ)‖,‖(θ−ℑω)+b2(θ−ℑ2ω)+b3(θ−ℑ3ω)+⋯+bu(θ−ℑuω)‖)={15[‖(u+1)(θ−ω)+(u+1)ω−u+12‖+‖(u+1)(ω−θ)+(u+1)θ−u+12‖]if u is odd,15[‖(u+1)(θ−ω)+uω−u2‖+‖(u+1)(ω−θ)+uθ−u2‖] if u is even,≥{(u+1)5‖θ−ω‖ if u is odd,(u+2)5‖θ−ω‖ if u is even,≥{‖θ−ω‖ if u is odd,65‖θ−ω‖if u is even. |
Case 2. For all ω∈[−1,−13] or θ∈[1,13], we get
‖b1(ω−θ)+ℑω−ℑθ+b2(ℑ2ω−ℑ2θ)+b3(ℑ3ω−ℑ3θ)+⋯+bu(ℑuω−ℑuθ)‖=‖(ω−θ)+(θ−ω−1)+(1+ω−θ)+(θ−ω−1)+⋯+(−1)u(1+ω−θ)‖={1,if u is odd,‖ω−θ‖,if u is even, |
and
ℏ((u∑j=1bj+1)‖ω−θ‖,‖(u∑j=1bj+1)(θ−ω)+(ω−ℑω)+b2(ω−ℑ2ω)+b3(ω−ℑ3ω)+⋯+bu(ω−ℑuω)‖,‖(u∑j=1bj+1)(ω−θ)+(θ−ℑθ)+b2(θ−ℑ2θ)+b3(θ−ℑ3θ)+⋯+bu(θ−ℑuθ)‖,‖(θ−ℑω)+b2(θ−ℑ2ω)+b3(θ−ℑ3ω)+⋯+bu(θ−ℑuω)‖)={15[‖(u+1)(θ−ω)+(u+1)ω−u+12‖+‖(u+1)(ω−θ)+(u+1)θ−u+12‖]if u is odd,15[‖(u+1)(θ−ω)+uω−u2‖+‖(u+1)(ω−θ)+uθ−u2‖] if u is even,≥{(u+1)5‖θ−ω‖ if u is odd,(u+2)5‖θ−ω‖ if u is even,≥{‖θ−ω‖ if u is odd,65‖θ−ω‖if u is even. |
Verifying the conditions in the aforementioned cases confirms the validity of (2.2). Therefore, ℑ qualifies as an HEF′-C and 12∈[13,1] is a unique FP of ℑ.
Remark 2.1. The weak ECM in [28] is obtained if we select ℏ(ϰ,ϱ,ξ,υ)=κϰ,0≤κ<1, and bj=0, for j=3,4,⋯,u in Definition 2.2 or 2.3.
Hence, through the selection of suitable functions ℏ and values bj (for j=1,2,⋯,u), we can derive modified weak enriched variants of the traditional contractions discussed, which, as far as we are aware, have not been explored previously.
Definition 2.4. Describe ℏ∈F as ℏ(ϰ,ϱ,ξ,υ)=κ(ϱ+ξ),0≤κ<12 and bj=0, for j=3,4,⋯,u in Definition 2.2. Then, the mapping ℑ is called an enriched Kannan-contraction (EKC), that is, there are b1,b2>0 and 0≤κ<12 such that
‖b1(ω−θ)+ℑω−ℑθ+b2(ℑ2ω−ℑ2θ)‖≤κ[‖(ω−ℑω)+b2(ω−ℑ2ω)‖+‖(θ−ℑθ)+b2(θ−ℑ2θ)‖], |
for all ω,θ∈Ω.
Definition 2.5. Describe ℏ∈F as ℏ(ϰ,ϱ,ξ,υ)=κ(ϱ+ξ),0≤κ<12 and bj=0, for j=3,4,⋯,u in Definition 2.3. Then, the mapping ℑ is called an enriched Chatterjea-contraction (ECC), that is, there are b1,b2>0 and 0≤κ<12 such that
‖b1(ω−θ)+ℑω−ℑθ+b2(ℑ2ω−ℑ2θ)‖≤κ[‖(1+b1+b2)(θ−ω)+(ω−ℑω))+b2(ω−ℑ2ω)‖+‖(1+b1+b2)(ω−θ)+(θ−ℑθ))+b2(θ−ℑ2θ)‖] |
for all ω,θ∈Ω.
Definition 2.6. Describe ℏ∈F as ℏ(ϰ,ϱ,ξ,υ)=κϰ+μ(ϱ+ξ),κ,μ≥0 with κ+2μ<1. Set bj=0, for j=3,4,⋯,u in Definition 2.2. Then, the mapping ℑ is called an enriched Ć irić-Reich-Rus-contraction (ECRRC), that is, there are b1,b2>0 and κ,μ≥0 with κ+2μ<1 such that
‖b1(ω−θ)+ℑω−ℑθ+b2(ℑ2ω−ℑ2θ)‖≤κ‖ω−θ‖+μ[‖(ω−ℑω))+b2(ω−ℑ2ω)‖+‖(θ−ℑθ))+b2(θ−ℑ2θ)‖] |
for all ω,θ∈Ω.
Definition 2.7. Describe ℏ∈F as ℏ(ϰ,ϱ,ξ,υ)=ϱκξ1−κ,0<κ<1 and put bj=0, for j=3,4,⋯,u in Definition 2.2. Then, the mapping ℑ is called an enriched interpolative Kannan-contraction (EIKC), that is, there are b1,b2>0 and 0<κ<1 such that
‖b1(ω−θ)+ℑω−ℑθ+b2(ℑ2ω−ℑ2θ)‖≤‖(ω−ℑω))+b2(ω−ℑ2ω)‖κ‖(θ−ℑθ))+b2(θ−ℑ2θ)‖1−κ |
for all ω,θ∈Ω.
Definition 2.8. Describe ℏ∈F as ℏ(ϰ,ϱ,ξ,υ)=ϰκϱμξ1−κ−μ,0<κ,μ<1 and put bj=0, for j=3,4,⋯,u in Definition 2.2. Then, the mapping ℑ is called an enriched interpolative Ćirić–Reich–Rus-contraction (EICRRC), that is, there are b1,b2>0 and 0<κ+μ<1 with κ+2μ<1 such that
‖b1(ω−θ)+ℑω−ℑθ+b2(ℑ2ω−ℑ2θ)‖≤‖ω−θ‖κ‖(ω−ℑω))+b2(ω−ℑ2ω)‖μ‖(θ−ℑθ))+b2(θ−ℑ2θ)‖1−κ−μ |
for all ω,θ∈Ω.
Remark 2.2. When b2 is set to 0 in Definitions 2.2 and 2.4–2.8, we derive enriched adaptations of the ECM introduced by Berinde [15], Kanan [29], EIKC [30], and EICRRCs, respectively.
Let's revisit the definitions of well-posedness, the limit shadowing property of a mapping, and the Ulam-Hyers (UH) stability concerning the FP equation.
Assume that ℑ:Ω→Ω is a mapping on an MS (Ω,d).
Definition 2.9. The FP issue Fix(ℑ) is deemed well-posed when ℑ possesses a unique FP ω∗, and for any sequence {ωm} in Ω where limm→∞d(ωm,ℑωm)=0, it follows that limm→∞d(ωm,ω∗)=0.
Definition 2.10. The FP challenge Fix(ℑ) is considered to exhibit the limit shadowing property in Ω if for any sequence Ω where limm→∞d(ωm,ℑωm)=0, there exists φ∈Ω such that limm→∞(ℑωm,ωm)=0.
Definition 2.11. The FP equation ω=ℑω demonstrates UH stability if there exists a constant δ>0 such that for every ϵ>0 and each ϖ∗∈Ω where d(ϖ∗,ℑϖ∗)≤ϵ, there exists ω∗∈Ω satisfying ℑω∗=ω∗ and d(ω∗,ϖ∗)≤δϵ.
We begin with the outcome concerning the existence and uniqueness of an FP for a u-fold AM associated with these two categories of hybrid enriched contractions within a BS context.
Theorem 2.1. Let Ω be a BS and ℑ:Ω→Ω be an HEF-C mapping. Then, there are κj>0,j=1,2,3,⋯,u,u≥4,u∈N, with ∑uj=1∈(0,1] such that the assertions below are true:
(i) The m-fold AM ˆℑ associated with ℑ owns a unique FP;
(ii) KI described as ωm=ˆℑωm−1, for any ω0∈Ω, i.e., for m∈N, the sequence {ωm} defined by
ωm=(1−κ1−κ2−κ3−⋯−κu)ωm−1+κ1ℑωm−1+κ2ℑ2ωm−1+κ3ℑ3ωm−1+⋯+κuℑuωm−1 |
converges to a unique FP of ˆℑ.
Proof. Since ℑ is an HEF-C, there exist bj≥0,j=1,2,3,⋯,u,u≥4,u∈N fulfilling the inequality (2.1). Consider κ1=1∑uj=1bj+1>0 and κs=bs∑uj=1bj+1≥0,s=2,3,⋯,u. Then, the inequality (2.1) can be written as
‖(1−κ2−κ3−⋯−κuκ1−1)(ω−θ)+ℑω−ℑθ+κ2κ1(ℑ2ω−ℑ2θ)+κ3κ1(ℑ3ω−ℑ3θ)+⋯+κuκ1(ℑuω−ℑuθ)‖≤ℏ(1κ1‖ω−θ‖,‖(ω−ℑω)+κ2κ1(ω−ℑ2ω)+κ3κ1(ω−ℑ3ω)+⋯+κuκ1(ω−ℑuω)‖,‖(θ−ℑθ)+κ2κ1(θ−ℑ2θ)+κ3κ1(θ−ℑ3θ)+⋯+κuκ1(θ−ℑuθ)‖,‖(θ−ℑω)+κ2κ1(θ−ℑ2ω)+κ3κ1(θ−ℑ3ω)+⋯+κuκ1(θ−ℑuω)‖), |
for ω,θ∈Ω. Because κ1>0 and (ℏ3) holds, we have
‖(1−κ1−κ2−κ3−⋯−κu)(ω−θ)+κ1(ℑω−ℑθ)+κ2(ℑ2ω−ℑ2θ)+κ3(ℑ3ω−ℑ3θ)+⋯+κu(ℑuω−ℑuθ)‖≤κ1ℏ(1κ1‖ω−θ‖,‖(ω−ℑω)+κ2κ1(ω−ℑ2ω)+κ3κ1(ω−ℑ3ω)+⋯+κuκ1(ω−ℑuω)‖,‖(θ−ℑθ)+κ2κ1(θ−ℑ2θ)+κ3κ1(θ−ℑ3θ)+⋯+κuκ1(θ−ℑuθ)‖,‖(θ−ℑθ)+κ2κ1(θ−ℑ2θ)+κ3κ1(θ−ℑ3θ)+⋯+κuκ1(θ−ℑuθ)‖)≤ℏ(‖ω−θ‖,‖κ1(ω−ℑω)+κ2(ω−ℑ2ω)+κ3(ω−ℑ3ω)+⋯+κu(ω−ℑuω)‖,‖κ1(θ−ℑθ)+κ2(θ−ℑ2θ)+κ3(θ−ℑ3θ)+⋯+κu(θ−ℑuθ)‖,‖κ1(θ−ℑω)+κ2(θ−ℑ2ω)+κ3(θ−ℑ3ω)+⋯+κu(θ−ℑuω)‖). |
This coupled with Definition 2.1, signifies that for ω,θ∈Ω,
‖ˆℑω−ˆℑθ‖≤ℏ(‖ω−θ‖,‖ω−ˆℑω‖,‖θ−ˆℑθ‖,‖θ−ˆℑω‖). | (2.3) |
Assume that ω0∈Ω is an arbitrary element and describe the sequence {ωm}m∈N as ωm=ˆℑmω0 for m≥1. Setting ω=ωm and θ=ωm−1 in (2.3), and using (ℏ4), one can write
‖ωm+1−ωm‖≤ℏ(‖ωm−ωm−1‖,‖ωm−ωm+1‖,‖ωm−1−ωm‖,‖ωm−1−ωm+1‖)≤ℏ(‖ωm−ωm−1‖,‖ωm−ωm+1‖,‖ωm−1−ωm‖,‖ωm−1−ωm‖+‖ωm−ωm+1‖). |
By the condition (ℏ2), there is ζ∈[0,1) such that
‖ωm+1−ωm‖≤ζ‖ωm−ωm−1‖. |
Through iterating this procedure, we deduce that
‖ωm+1−ωm‖≤ζm‖ω1−ω0‖. |
Next, for j,m≥1, one has
‖ωm+j−ωm‖≤‖ωm+j−ωm+j−1‖+‖ωm+j−1−ωm+j−2‖+⋯+‖ωm+1−ωm‖≤(ζm+j−1+ζm+j−2+⋯+ζm)‖ω1−ω0‖=ζm(1−ζj)1−ζ‖ω1−ω0‖, |
which implies that the sequence {ωm} is a Cauchy sequence in Ω. Thus, there is ω∗∈Ω such that limm→∞ωm=ω∗.
Now, setting ω=ω∗ and θ=ωm in (2.3), we can write
‖ˆℑω∗−ˆℑωm‖≤ℏ(‖ω∗−ωm‖,‖ω∗−ˆℑω∗‖,‖ωm−ˆℑωm‖,‖ωm−ˆℑω∗‖). | (2.4) |
Letting m→∞ in (2.4), we have
‖ˆℑω∗−ω∗‖≤ℏ(‖ω∗−ω∗‖,‖ω∗−ˆℑω∗‖,‖ω∗−ω∗‖,‖ω∗−ˆℑω∗‖). |
From the conditions (ℏ1) and (ℏ2), we have
‖ˆℑω∗−ω∗‖≤ℏ(‖ω∗−ω∗‖,‖ω∗−ˆℑω∗‖,‖ω∗−ω∗‖,‖ω∗−ˆℑω∗‖)≤ζ‖ω∗−ω∗‖=0. |
Thus, ˆℑω∗=ω∗. For the uniqueness, assume that η1 and η2 are distinct FPs of ˆℑ. Putting ω=η1 and θ=η2 in (2.3), we get
‖η1−η2‖=‖ˆℑη1−ˆℑη2‖≤ℏ(‖η1−η2‖,‖η1−ℑ′η1‖,‖η2−ℑ′η2‖,‖η2−ℑ′η1‖)=ℏ(‖η1−η2‖,‖η1−η1‖,‖η2−η2‖,‖η2−η1‖)=ℏ(‖η1−η2‖,0,0,‖η2−η1‖)≤ζ.0=0, |
which implies that η1=η2. This completes the proof.
Theorem 2.2. Let Ω be a BS and ℑ:Ω→Ω be an HEF′-C. Then, there exist κj>0,j=1,2,3,⋯,u,u≥4,u∈N, with ∑uj=1κj∈(0,1] such that the following assertions hold:
(i) The m-fold AM ˆℑ associated with ℑ possesses a unique FP;
(ii) KI defined by ωm=ˆℑωm−1, for any ω0∈Ω, converges to a unique FP of ˆℑ.
Proof. Because ℑ is an HEF′-C, there exist bj≥0,j=1,2,3,⋯,u,u≥4,u∈N justifying the inequality (2.2). Assume that κ1=1∑uj=1bj+1>0 and κs=bs∑uj=1bj+1≥0,s=2,3,⋯,u. Then, the inequality (2.1) takes the form
‖(1−κ2−κ3−⋯−κuκ1−1)(ω−θ)+ℑω−ℑθ+κ2κ1(ℑ2ω−ℑ2θ)+κ3κ1(ℑ3ω−ℑ3θ)+⋯+κuκ1(ℑuω−ℑuθ)‖≤ℏ(1κ1‖ω−θ‖,‖1κ1(θ−ω)+(ω−ℑω)+κ2κ1(ω−ℑ2ω)+κ3κ1(ω−ℑ3ω)+⋯+κuκ1(ω−ℑuω)‖,‖1κ1(ω−θ)+(θ−ℑθ)+κ2κ1(θ−ℑ2θ)+κ3κ1(θ−ℑ3θ)+⋯+κuκ1(θ−ℑuθ)‖,‖(θ−ℑω)+κ2κ1(θ−ℑ2ω)+κ3κ1(θ−ℑ3ω)+⋯+κuκ1(θ−ℑuω)‖), |
for ω,θ∈Ω. As κ1>0 and (ℏ′3) holds, we get
‖(1−κ1−κ2−κ3−⋯−κu)(ω−θ)+κ1(ℑω−ℑ)θ+κ2(ℑ2ω−ℑ2θ)+κ3(ℑ3ω−ℑ3θ)+⋯+κu(ℑuω−ℑuθ)‖≤κ1ℏ(1κ1‖ω−θ‖,‖1κ1(θ−ω)+(ω−ℑω)+κ2κ1(ω−ℑ2ω)+κ3κ1(ω−ℑ3ω)+⋯+κuκ1(ω−ℑuω)‖,‖1κ1(ω−θ)+(θ−ℑθ)+κ2κ1(θ−ℑ2θ)+κ3κ1(θ−ℑ3θ)+⋯+κuκ1(θ−ℑuθ)‖,‖(θ−ℑω)+κ2κ1(θ−ℑ2ω)+κ3κ1(θ−ℑ3ω)+⋯+κuκ1(θ−ℑuω)‖),≤ℏ(‖ω−θ‖,‖(θ−ω)+κ1(ω−ℑω)+κ2(ω−ℑ2ω)+κ3(ω−ℑ3ω)+⋯+κu(ω−ℑuω)‖,‖(ω−θ)+κ1(θ−ℑθ)+κ2(θ−ℑ2θ)+κ3(θ−ℑ3θ)+⋯+κu(θ−ℑuθ)‖,‖κ1(θ−ℑω)+κ2(θ−ℑ2ω)+κ3(θ−ℑ3ω)+⋯+κu(θ−ℑuω)‖). |
This coupled with Definition 2.1, signifies that for ω,θ∈Ω,
‖ˆℑω−ˆℑθ‖≤ℏ(‖ω−θ‖,‖θ−ˆℑω‖,‖ω−ˆℑθ‖,‖θ−ˆℑω‖). | (2.5) |
Let ω0∈Ω be an arbitrary element and define the sequence {ωm}m∈N as ωm=ˆℑmω0 for m≥1. Putting ω=ωm and θ=ωm−1 in (2.5), and using (ℏ′4), we can write
‖ωm+1−ωm‖≤ℏ(‖ωm−ωm−1‖,‖ωm−1−ωm+1‖,‖ωm−ωm‖,‖ωm−1−ωm+1‖)≤ℏ(‖ωm−ωm−1‖,‖ωm−1−ωm‖+‖ωm−ωm+1‖,0,‖ωm−1−ωm‖+‖ωm−ωm+1‖). |
By the condition (ℏ′2), there is ζ∈[0,1) such that
‖ωm+1−ωm‖≤ζ‖ωm−1−ωm‖. |
Repeating this process, we have
‖ωm+1−ωm‖≤ζm‖ω1−ω0‖. |
Next, for j,m≥1, one has
‖ωm+j−ωm‖≤‖ωm+j−ωm+j−1‖+‖ωm+j−1−ωm+j−2‖+⋯+‖ωm+1−ωm‖≤(ζm+j−1+ζm+j−2+⋯+ζm)‖ω1−ω0‖=ζm(1−ζj)1−ζ‖ω1−ω0‖, |
which implies that the sequence {ωm} is a Cauchy sequence in Ω. Thus, there is ω∗∈Ω such that limm→∞ωm=ω∗.
Now, setting ω=ω∗ and θ=ωm in (2.5), we can write
‖ˆℑω∗−ˆℑωm‖≤ℏ(‖ω∗−ωm‖,‖ωm−ˆℑω∗‖,‖ωm−ˆℑω∗‖,‖ωm−ˆℑω∗‖). | (2.6) |
When m→∞ in (2.6), we have
‖ˆℑω∗−ω∗‖≤ℏ(‖ω∗−ω∗‖,‖ω∗−ˆℑω∗‖,‖ω∗−ˆℑω∗‖,‖ω∗−ˆℑω∗‖). |
From the conditions (ℏ′1) and (ℏ′2), we get
‖ˆℑω∗−ω∗‖≤ℏ(‖ω∗−ω∗‖,‖ω∗−ˆℑω∗‖,‖ω∗−ˆℑω∗‖,‖ω∗−ˆℑω∗‖)≤ζ‖ω∗−ω∗‖=0. |
and ˆℑω∗=ω∗.
Finally, assume that η1 and η2 are distinct FPs of ℑ′. Putting ω=η1 and θ=η2 in (2.5), we get
‖η1−η2‖=‖ˆℑη1−ˆℑη2‖≤ℏ(‖η1−η2‖,‖η2−ℑ′η1‖,‖η1−ℑ′η2‖,‖η2−ℑ′η1‖)=ℏ(‖η1−η2‖,‖η2−η1‖,‖η1−η2‖,‖η2−η1‖) |
By (ℏ′5), we deduce that ‖η1−η2‖=0. Thus, ˆℑ has a unique FP.
Remark 2.3. In Theorems 2.1 and 2.2, if we take ℏ(ϰ,ϱ,ξ,υ)=κϰ,κ∈[0,1), and bj=0,j=3,4,⋯u, we have Theorem 2.3 in [28].
Corollary 2.1. Let Ω be a BS and ℑ:Ω→Ω is an EKC (or ECRRC, ECC, EIKC, EICRRC). Then there are κ1,κ2>0 with κ1+κ2∈(0,1] such that the assertions below are true:
(i) The 2−fold AM ℑκ1,κ2 owns a unique FP;
(ii) KI {ωm} defined by ωm=ℑκ1,κ2ωm−1, for any ω0∈Ω, that is, the sequence {ωm} described as
ωm=(1−κ1−κ2)ωm−1+κ1ℑωm−1+κ2ℑ2ωm−1,m∈N |
converges to a unique FP of ℑκ1,κ2.
Proof. The proof can be simplified as follows:
− Choosing ℏ(ϰ,ϱ,ξ,υ)=κ(ϱ+ξ), where κ∈[0,12) in Theorem 2.1, we have the FP theorems for EKC.
− Selecting ℏ(ϰ,ϱ,ξ,υ)=ρϰ+σ(ϱ+ξ),ρ,σ∈[0,1) with ρ+2σ<1 in Theorem 2.1, we have the FP theorems for ECRRC.
− Taking ℏ(ϰ,ϱ,ξ,υ)=ϰκξ1−κ, where κ∈(0,1) in Theorem 2.1, we have the FP theorems for EIKC.
− Putting ℏ(ϰ,ϱ,ξ,υ)=ϰκϱλξ1−κ−λ, where κ,λ∈(0,1) with κ+λ<1 in Theorem 2.1, we have the FP theorems for EICRRC.
− Setting ℏ(ϰ,ϱ,ξ,υ)=κ(ϱ+ξ), where κ∈[0,12) in Theorem 2.2, we have the FP theorems for ECC.
Remark 2.4. In Corollary 2.1, if we put κ2=0, we get the FP theorems corresponding to EKC, ECC, ECRRC, EIKC, and EICRRC in [30,31,32].
Next, we require the subsequent definitions and notations:
Definition 2.12. [33] Assume that (Ω,‖.‖) is an NS and ℑ:Ω→Ω is a given mapping. The diameter of a set B, represented as ϕ[B], is described as {sup‖ω−θ‖:ω,θ∈B}, where B is a bounded subset of Ω.
An NS (Ω,‖.‖) is termed as ℑ− orbital BS if every Cauchy sequence within Q(ℑ,ω,∞) for a given ω∈Ω converges in Ω.
We will now demonstrate the lemmas below for the category of HEF-Cs (or HEF′-Cs).
Lemma 2.1. Let (Ω,‖.‖) be an NS and ℑ:Ω→Ω be an HEF-C mapping (or HEF′-C mapping). Assume that the following statements hold:
(S) For each HEF-C, there is δ∈[0,1) such that
ℏ((u∑j=1bj+1)‖ω−θ‖,‖(ω−ℑω)+b2(ω−ℑ2ω)+b3(ω−ℑ3ω)+⋯+bu(ω−ℑuω)‖,‖(θ−ℑθ)+b2(θ−ℑ2θ)+b3(θ−ℑ3θ)+⋯+bu(θ−ℑuθ)‖,‖(θ−ℑω)+b2(θ−ℑ2ω)+b3(θ−ℑ3ω)+⋯+bu(θ−ℑuω)‖)≤δmax{(u∑j=1bj+1)‖ω−θ‖,‖(ω−ℑω)+b2(ω−ℑ2ω)+b3(ω−ℑ3ω)+⋯+bu(ω−ℑuω)‖,‖(θ−ℑθ)+b2(θ−ℑ2θ)+b3(θ−ℑ3θ)+⋯+bu(θ−ℑuθ)‖,‖(u∑j=1bj+1)(θ−ω)+(ω−ℑω)+b2(ω−ℑ2ω)+b3(ω−ℑ3ω)+⋯+bu(ω−ℑuω)‖,‖(u∑j=1bj+1)(ω−θ)+(θ−ℑθ)+b2(θ−ℑ2θ)+b3(θ−ℑ3θ)+⋯+bu(θ−ℑuθ)‖} |
or
(S′) for each HEF-C, there is δ∈[0,1) such that
ℏ((u∑j=1bj+1)‖ω−θ‖,‖(u∑j=1bj+1)(θ−ω)+(ω−ℑω)+b2(ω−ℑ2ω)+b3(ω−ℑ3ω)+⋯+bu(ω−ℑuω)‖,‖(u∑j=1bj+1)(ω−θ)+(θ−ℑθ)+b2(θ−ℑ2θ)+b3(θ−ℑ3θ)+⋯+bu(θ−ℑuθ)‖,‖(θ−ℑω)+b2(θ−ℑ2ω)+b3(θ−ℑ3ω)+⋯+bu(θ−ℑuω)‖)≤δmax{(u∑j=1bj+1)‖ω−θ‖,‖(ω−ℑω)+b2(ω−ℑ2ω)+b3(ω−ℑ3ω)+⋯+bu(ω−ℑuω)‖,‖(θ−ℑθ)+b2(θ−ℑ2θ)+b3(θ−ℑ3θ)+⋯+bu(θ−ℑuθ)‖,‖(u∑j=1bj+1)(θ−ω)+(ω−ℑω)+b2(ω−ℑ2ω)+b3(ω−ℑ3ω)+⋯+bu(ω−ℑuω)‖,‖(u∑j=1bj+1)(ω−θ)+(θ−ℑθ)+b2(θ−ℑ2θ)+b3(θ−ℑ3θ)+⋯+bu(θ−ℑuθ)‖} |
for all ω,θ∈Ω, bj∈(0,∞),j=1,2,3,⋯,u,u≥4,u∈N.
Then, there exist κj>0,j=1,2,3,⋯,u,u≥4,u∈N, with ∑uj=1κj∈(0,1] so that for each ω∈Ω and for all r,l∈{1,2,3,⋯,m} for a positive integer m, we have
‖ˆℑrω−ˆℑlω‖≤δϕ[Q(ℑ′,ω,m)], |
where ˆℑ is the u-fold AM linked to an HEF-C (or HEF′-C).
Proof. As ℑ is a HEF-C, there is bj∈(0,∞),j=1,2,3,⋯,u,u≥4,u∈N, fulfilling the inequality (1.1). Consider κ1=1∑uj=1bj+1>0 and κs=bs∑uj=1bj+1≥0,s=2,3,⋯,u. Then, the inequality (2.1) takes the form
‖(1−κ2−κ3−⋯−κuκ1−1)(ω−θ)+ℑω−ℑθ+κ2κ1(ℑ2ω−ℑ2θ)+κ3κ1(ℑ3ω−ℑ3θ)+⋯+κuκ1(ℑuω−ℑuθ)‖≤ℏ(1κ1‖ω−θ‖,‖(ω−ℑω)+κ2κ1(ω−ℑ2ω)+κ3κ1(ω−ℑ3ω)+⋯+κuκ1(ω−ℑuω)‖,‖(θ−ℑθ)+κ2κ1(θ−ℑ2θ)+κ3κ1(θ−ℑ3θ)+⋯+κuκ1(θ−ℑuθ)‖,‖(θ−ℑω)+κ2κ1(θ−ℑ2ω)+κ3κ1(θ−ℑ3ω)+⋯+κuκ1(θ−ℑuω)‖). |
With the help of Assertion (S), the above inequality reduces to
‖ˆℑω−ˆℑθ‖≤ℏ(‖ω−θ‖,‖ω−ˆℑω‖,‖θ−ˆℑθ‖,‖θ−ˆℑω‖)≤cmax{‖ω−θ‖,‖ω−ˆℑω‖,‖θ−ˆℑθ‖,‖θ−ˆℑω‖,‖ω−ˆℑθ‖}. | (2.7) |
For a fixed positive integer m, assume that ω∈Ω is an arbitrary point. From (2.7), we get
‖ˆℑrω−ˆℑlω‖=‖ˆℑˆℑr−1ω−ˆℑˆℑl−1ω‖≤cmax{‖ˆℑr−1ω−ˆℑl−1ω‖,‖ˆℑr−1ω−ˆℑrω‖,‖ˆℑl−1ω−ˆℑlω‖,‖ˆℑl−1ω−ˆℑrω‖,‖ˆℑr−1ω−ˆℑlω‖}, |
which yields
‖ˆℑrω−ˆℑlω‖≤δϕ[Q(ˆℑ,ω,m)]. |
A comparable conclusion for HEF′-C with Assertion (S′) can be reached by employing reasoning akin to the ones mentioned earlier.
Remark 2.5. Based on Lemma 2.1, if ℑ is an HEF-C (or HEF′-C) and ω∈Ω, then for any positive integer m, there exists s≤m such that
‖ω−ˆℑsω‖=ϕ[Q(ˆℑ,ω,m)]. |
Lemma 2.2. Let (Ω,‖.‖) be an NS and ℑ:Ω→Ω be an HEF-C (or HEF′-C). For a positive integer m, assume that there exists δ∈[0,1) such that Assertion (S) (or (S′)) is verified. Then, there are κj>0,j=1,2,3,⋯,u,u≥4,u∈N, with ∑uj=1κj∈(0,1] so that
ϕ[Q(ˆℑ,ω,∞)]≤11−δ‖ω−ˆℑω‖, for all ω∈Ω, |
where ˆℑ is the u-fold AM linked to a HEF-C (or HEF′-C).
Proof. Because ℑ is an HEF-C, there is bj∈(0,∞),j=1,2,3,⋯,u,u≥4,u∈N, fulfilling the inequality (1.1). Consider κ1=1∑uj=1bj+1>0 and κs=bs∑uj=1bj+1≥0,s=2,3,⋯,u.
Assume that ω∈Ω is an arbitrary element. Since the sequence {ϕ[Q(ˆℑ,ω,m)]} is increasing, we get
ϕ[Q(ˆℑ,ω,∞)]=sup{ϕ[Q(ˆℑ,ω,m)]:m∈N}. |
Then (2.7) is fulfilled if we prove that
ϕ[Q(ˆℑ,ω,m)]≤11−δ‖ω−ˆℑω‖, m∈N. |
Assume that m is a positive integer. Utilizing Remark 2.5 there is ˆℑsω∈Q(ˆℑ,ω,m), where s∈[1,m] in order that
‖ω−ˆℑsω‖=ϕ[Q(ˆℑ,ω,m)]. |
It follows from the triangle inequality and Lemma 2.1 that
‖ω−ˆℑsω‖≤‖ω−ˆℑω‖+‖ˆℑω−ˆℑsω‖≤‖ω−ˆℑω‖+δϕ[Q(ˆℑ,ω,m)]=‖ω−ˆℑω‖+δ‖ω−ˆℑsω‖. |
Hence,
ϕ[Q(ˆℑ,ω,m)]=‖ω−ˆℑsω‖≤11−δ‖ω−ˆℑω‖, for all m∈N. |
A comparable conclusion for HEF′-C with Assertion (S′) can be reached by employing reasoning akin to the ones mentioned earlier.
Theorem 2.3. Let ℑ be an HEF′-C (or HEF′-C) on an NS (Ω,‖.‖). For a positive integer m, assume that there exists δ∈[0,1) such that Assertion (S) (or (S′)) is satisfied. Then, there are κj>0,j=1,2,3,⋯,u,u≥4,u∈N, with ∑uj=1κj∈(0,1] so that the assumptions below hold, provided that Ω is a ˆℑ−orbital BS:
(i) The m-fold AM ˆℑ associated with ℑ has a unique FP;
(ii) KI defined by ωm=ˆℑωm−1, for any ω0∈Ω converges to a unique FP of ˆℑ.
Proof. Utilizing reasoning akin to that in the proof of Lemma 2.1, for κ1=1∑uj=1bj+1>0 and κs=bs∑uj=1bj+1≥0,s=2,3,⋯,u, one has
‖ˆℑω−ˆℑθ‖≤cmax{‖ω−θ‖,‖ω−ˆℑω‖,‖θ−ˆℑθ‖,‖θ−ˆℑω‖,‖ω−ˆℑθ‖}. | (2.8) |
Consider ω0∈Ω. Describe the KI {ωm} as ωm=ˆℑωm−1=ˆℑmω0,m∈N.
Next, we demonstrate that the sequence of iterates {ωm} forms a Cauchy sequence. Assume that m and j are positive integers with j<m. From Lemma 2.1, one can write
‖ωj−ωm‖=‖ˆℑjω0−ˆℑmω0‖=‖ˆℑˆℑj−1ω0−ˆℑˆℑm−1ω0‖=‖ˆℑωj−1−ˆℑm−j−1ωj−1‖≤δϕ[Q(ˆℑ,ωj−1,m−j+1)]. |
It follows from Remark 2.5 that there is an integer z,z∈[1,m−j+1] in order that
‖ωj−1−ωj+z−1‖=ϕ[Q(ˆℑ,ωj−1,m−j+1)]. |
Utilizing Lemma 2.1, we get
‖ωj−1−ωj+z−1‖=‖ˆℑωj−2−ˆℑz+1ωj−2‖≤δϕ[Q(ˆℑ,ωj−2,z+1)], |
which yields
‖ωj−1−ωj+z−1‖≤δϕ[Q(ˆℑ,ωj−2,m−j+2)]. |
Thus, one can write
‖ωj−ωm‖≤δϕ[Q(ˆℑ,ωj−1,m−j+1)]≤δ2ϕ[Q(ˆℑ,ωj−2,m−j+2)]. |
Continuing with this process, we obtain
‖ωj−ωm‖≤δϕ[Q(ˆℑ,ωj−1,m−j+1)]≤⋯≤δjϕ[Q(ˆℑ,ω0,m)]. |
Applying Lemma 2.2, we have
‖ωj−ωm‖≤δj1−δ‖ω0−ˆℑω0‖. | (2.9) |
Passing m→∞ in (2.9), we conclude that {ωm} forms a Cauchy sequence. As Ω is a ˆℑ−orbital BS, there is ω∗∈Ω such that ωm→ω∗ as m→∞. Clearly,
‖ω∗−ˆℑω∗‖≤‖ω∗−ωm+1‖+‖ωm+1−ˆℑω∗‖=‖ω∗−ωm+1‖+‖ˆℑωm−ˆℑω∗‖≤‖ω∗−ωm+1‖+δmax{‖ωm−ω∗‖,‖ωm−ωm+1‖,‖ω∗−ˆℑω∗‖,‖ω∗−ωm+1‖,‖ωm−ˆℑω∗‖}≤‖ω∗−ωm+1‖+δ{‖ωm−ω∗‖+‖ωm−ωm+1‖+‖ω∗−ˆℑω∗‖+‖ω∗−ωm+1‖+‖ωm−ˆℑω∗‖}. |
Hence,
‖ω∗−ˆℑω∗‖≤11−2δ{(1+δ)‖ω∗−ωm+1‖+δ‖ωm−ω∗‖+δ‖ωm−ωm+1‖} |
Since ωm→ω∗ as m→∞, we have ‖ω∗−ˆℑω∗‖=0. Thus, ω∗=ˆℑω∗, that is, ω∗ is a FP of ˆℑ. The uniqueness follows immediately from (2.8).
A comparable conclusion for HEF′-C with Assertion (S′) can be reached by employing reasoning akin to the ones mentioned earlier.
Subsequently, we will examine the well-posedness and limit shadowing property for each category of hybrid enriched contractions defined in this context.
Theorem 2.4. Let Ω be a BS. Then, Fix(ˆℑ) is well posed, provided that ℑ is an HEF-C mapping.
Proof. Thanks to Theorem 2.1, ˆℑ has a unique FP ω∗ in Ω. Assume that limm→∞‖ˆℑωm−ωm‖=0. By (2.3), we get
‖ωm−ω∗‖≤‖ωm−ˆℑωm‖+‖ˆℑωm−ω∗‖=‖ωm−ˆℑωm‖+‖ˆℑωm−ˆℑω∗‖≤‖ωm−ˆℑωm‖+ℏ(‖ωm−ω∗‖,‖ωm−ˆℑωm‖,‖ω∗−ˆℑω∗‖,‖ω∗−ˆℑωm‖). |
Letting m→∞ in the above inequality, we have
limm→∞‖ωm−ω∗‖≤ℏ(limm→∞‖ωm−ω∗‖,0,0,0). |
Using (ℏ2), there is ζ∈[0,1) such that limm→∞‖ωm−ω∗‖≤ζ.0, which leads to limm→∞‖ωm−ω∗‖=0, thereby establishing the result.
Theorem 2.5. Let Ω be a BS. Then, Fix(ˆℑ) is well posed, provided that ℑ is an HEF′-C mapping.
Proof. The conclusion can be derived by employing reasoning analogous to that in the proof of Theorem 2.4.
Theorem 2.6. Let Ω be a BS and ℑ be a HEF-C (resp., HEF′-C). Then, Fix(ˆℑ) exhibits the limit shadowing property in Ω.
Proof. From Theorem 2.1 (resp., Theorem 2.2), we conclude that ˆℑ owns a unique FP ω∗ in Ω. Hence, ˆℑmω∗=ω∗ for any m∈N, assume that limm→∞‖ˆℑωm−ωm‖=0. It is clear that
‖ωm−ˆℑmω∗‖=‖ωm−ω∗‖≤‖ωm−ˆℑωm‖+‖ˆℑωm−ˆℑω∗‖≤‖ωm−ˆℑωm‖+ℏ(‖ωm−ω∗‖,‖ωm−ˆℑωm‖,‖ω∗−ˆℑω∗‖,‖ω∗−ˆℑωm‖)(resp., ℏ(‖ωm−ω∗‖,‖ω∗−ˆℑωm‖,‖ωm−ˆℑω∗‖,‖ω∗−ˆℑωm‖)). |
Setting m→∞ in the above inequality, and we have
limm→∞‖ωm−ˆℑmω∗‖≤ℏ(limm→∞‖ωm−ω∗‖,0,0,0)(resp., ℏ(limm→∞‖ωm−ω∗‖,limm→∞‖ω∗−ωm+1‖,limm→∞‖ωm−ω∗‖,limm→∞‖ω∗−ωm+1‖)). |
By (ℏ2)(resp., (ℏ′5)), we have limm→∞‖ωm−ˆℑmω∗‖=0, and this completes the proof.
To study UH stablility, we introduce the following theorems:
Theorem 2.7. Let Ω be a BS and ℑ be an HEF-C that fulfills the condition below:
(ℏ5) there is ζ∈(0,1) so that ℏ(ϰ,ϱ,ξ,υ)≤ζϰ+ξ for all ϰ,ϱ,ξ,υ∈R+.
Then, the FP equation ˆℑω=ω is UH stable.
Proof. Thanks to Theorem 2.1, ˆℑ has a unique FP ω∗ in Ω. Let ϵ>0 and υ∗∈Ω be an ϵ−solution, i.e.,
‖υ∗−ˆℑυ∗‖≤ϵ. |
As ω∗∈Ω and ‖ω∗−ˆℑω∗‖=0≤ϵ, then ω∗∈Ω is an ϵ−solution too. Using (ℏ5), we have
‖ω∗−υ∗‖=‖ˆℑω∗−υ∗‖≤‖ˆℑω∗−ˆℑυ∗‖+‖ˆℑυ∗−υ∗‖≤ℏ(‖ω∗−υ∗‖,‖ω∗−ˆℑω∗‖,‖υ∗−ˆℑυ∗‖,‖υ∗−ˆℑω∗‖)+‖ˆℑυ∗−υ∗‖=ℏ(‖ω∗−υ∗‖,0,‖υ∗−ˆℑυ∗‖,‖υ∗−ω∗‖)+‖ˆℑυ∗−υ∗‖≤ζ‖ω∗−υ∗‖+2‖ˆℑυ∗−υ∗‖≤ζ‖ω∗−υ∗‖+2ϵ, |
which yields
‖ω∗−υ∗‖≤Uϵ, |
where U=11−ζ. Hence, the result is proved.
Theorem 2.8. Let Ω be a BS and ℑ be an HEF′-C that fulfills the condition below:
(ℏ′6) there is ζ∈(0,13) so that ℏ(ϰ,ϱ,ξ,υ)≤ζ(2ϰ+ξ) for all ϰ,ϱ,ξ,υ∈R+.
Then, the FP equation ˆℑω=ω is UH stable.
Proof. Thanks to Theorem 2.2, ˆℑ has a unique FP ω∗ in Ω. Let ϵ>0 and υ∗∈Ω be an ϵ−solution, i.e.,
‖υ∗−ˆℑυ∗‖≤ϵ. |
As ω∗∈Ω and ‖ω∗−ˆℑω∗‖=0≤ϵ, then ω∗∈Ω is an ϵ−solution too. Using (ℏ′6), we can write
‖ω∗−υ∗‖=‖ˆℑω∗−υ∗‖≤‖ˆℑω∗−ˆℑυ∗‖+‖ˆℑυ∗−υ∗‖≤ℏ(‖ω∗−υ∗‖,‖υ∗−ˆℑω∗‖,‖ω∗−ˆℑυ∗‖,‖υ∗−ˆℑω∗‖)+‖ˆℑυ∗−υ∗‖≤ζ(2‖ω∗−υ∗‖+‖ω∗−ˆℑυ∗‖)+‖ˆℑυ∗−υ∗‖≤ζ(2‖ω∗−υ∗‖+(‖ω∗−υ∗‖+‖υ∗−ˆℑυ∗‖))+‖ˆℑυ∗−υ∗‖≤3ζ‖ω∗−υ∗‖+(1+ζ)ϵ, |
which yields
‖ω∗−υ∗‖≤Uϵ, |
where U=1+ζ1−3ζ. Hence, the result is proved.
Assuming the existence of an FP of a u-fold AM linked to an HEF-C mapping ℑ (or HEF′-C), we aim to investigate essential conditions for the equivalence of FP sets between the u-fold AM and the related ECM.
We will commence with the subsequent observation, established for AMs ℑϑ and double AMs ℑκ1,κ2.
Remark 3.1. Assume that ℑ is a self-mapping on an NS Ω. For κj>0,j=1,2,3,⋯,u,u≥4,u∈N, with ∑uj=1∈(0,1], the u-fold AM ˆℑ:Ω→Ω linked to ℑ is described as
ˆℑ=(1−κ1−κ2−κ3−⋯−κu)I+κ1ℑ+κ2ℑ2+κ3ℑ3+⋯+κuℑu, |
and has the property Fix(ℑ)⊆Fix(ˆℑ).
Next, we analyze the conditions ensuring the equivalence of Fix(ℑ) and Fix(ˆℑ).
Theorem 3.1. Let Ω be a BS and ℑ be an HEF-C (resp., HEF′-C). Suppose that κj>0,j=1,2,3,⋯,u,u≥4,u∈N, with ∑uj=1κj∈(0,1] fulfilling the following hypothesis:
(H1) for all hj∈(0,1),j=1,2,3,⋯,u with ∑uj=1hj∈[0,1) and ϰ∈Fix(ˆℑ),
‖ϰ−ℑϰ‖≤‖ϰ−(1−u∑j=2hj)ℑϰ−h2ℑ2ϰ−h3ℑ3ϰ−⋯−huℑuϰ‖. | (3.1) |
Then, Fix(ℑ)=Fix(ˆℑ).
Proof. We know from Remark 3.1 that Fix(ℑ)⊆Fix(ˆℑ). To demonstrate the reverse, suppose Fix(ˆℑ) is not empty. Otherwise, the conclusion is self-evident. According to Theorem 2.1 (resp., Theorem 2.2), we obtain Fix(ˆℑ)≠∅. If ϰ∈Fix(ˆℑ), then there is κj>0,j=1,2,3,⋯,u,u≥4,u∈N, with ∑uj=1κj∈(0,1] such that
ϰ=(1−κ1−κ2−κ3−⋯−κu)ϰ+κ1ℑϰ+κ2ℑ2ϰ+κ3ℑ3ϰ+⋯+κuℑuϰ. |
Put hj=κj∑uj=1κj,j=1,2,3,⋯,u, in (3.1), and we have
‖ϰ−ℑϰ‖≤‖ϰ−κ1∑uj=1κjℑϰ−κ2∑uj=1κjℑ2ϰ−κ3∑uj=1κjℑ3ϰ−⋯−κu∑uj=1κjℑuϰ‖=1∑uj=1κj‖ϰ−(1−κ1−κ2−κ3−⋯−κu)z−κ1ℑϰ−κ2ℑ2ϰ−κ3ℑ3ϰ−⋯−κuℑuϰ‖=‖ϰ−ˆℑϰ‖=0. |
Hence, ϰ∈Fix(ℑ). Therefore Fix(ℑ)=Fix(ˆℑ).
We can also obtain equality between Fix(ℑ) and Fix(ˆℑ) in another way, as follows:
Theorem 3.2. Let Ω be a BS and ℑ be an HEF-C (resp., HEF′-C). Suppose that there exist κj>0,j=1,2,3,⋯,u,u≥4,u∈N, with ∑uj=1κj∈(0,1] and ϑ∈[0,1) such that
(H2) for all ω∈Ω, we get
‖ˆℑω−ℑω‖≤ϑ‖ω−ℑω‖. |
Then, Fix(ℑ)=Fix(ˆℑ).
Proof. From Remark 3.1, we have Fix(ℑ)⊆Fix(ˆℑ). Based on Theorem 2.1 (resp., Theorem 2.2), we conclude that Fix(ˆℑ)≠∅. If ϰ∈Fix(ˆℑ), one has
‖ϰ−ℑϰ‖=‖ˆℑϰ−ℑϰ‖≤ϑ‖ϰ−ℑϰ‖, |
which implies that ‖ϰ−ℑϰ‖=0. Thus, ϰ∈Fix(ℑ). Hence, Fix(ˆℑ)⊆Fix(ℑ). Hence Fix(ℑ)=Fix(ˆℑ).
Subsequently, we derive an approximation of an FP for an HEF-C (resp., HEF′-C) by employing the KI method for ˆℑ.
Theorem 3.3. Let Ω be a BS and ℑ be an HEF-C (resp., HEF′-C). Suppose that (H1) or (H2) are satisfied. Then,
(i) ℑ possesses a unique FP in Ω;
(ii) KI defined by ωm=ˆℑωm−1, for any ω0∈Ω converges to a unique FP of ℑ.
Proof. According to Theorem 2.1 (resp., Theorem 2.2), there are κj>0,j=1,2,3,⋯,u,u≥4,u∈N, with ∑uj=1κj∈(0,1] such that ˆℑ is described as
ˆℑ=(1−κ1−κ2−κ3−⋯−κu)I+κ1ℑ+κ2ℑ2+κ3ℑ+⋯+κuℑu |
and has a unique FP ω∗∈Ω, which can be achieved through KI (2.1) for ω0∈Ω. Since κj(j=1,2,3,⋯,u) fulfills hypothesis (H1) or (H2), the result follows immediately by Theorem 3.1 or Theorem 3.2.
We finish this manuscript with revisiting the concept of the periodic point property (PPP) for a self-mapping ℑ described on Ω.
Definition 3.1. Assume that Ω is a nonempty set. We say that a mapping ℑ:Ω→Ω has the PPP Ξ if for every m∈N,Fix(ℑ)=Fix(ℑm).
Remark 3.2. (i) For all m∈N,Fix(ℑ)⊂Fix(ℑm). Nevertheless, the reverse is not necessarily valid in all cases.
(ii) The mapping ℑ owns the PPP Ξ if ℑϑ owns the PPP Ξ; indeed, Fix(ℑ)=Fix(ℑϑ).
Now, we investigate the conditions that ensure a self-mapping ℑ, which meets the hybrid ECM, and possesses the PPP Ξ.
Lemma 3.1. Assume that Ω is a BS and ℑ is an HEF-C (resp., HEF′-C). Assume also there are κj>0,j=1,2,3,⋯,u,u≥4,u∈N, with ∑uj=1κj∈(0,1] and
(H) for all ϵ>0, there are ω,θ∈Ω so that
‖ω−ˆℑθ‖<ϵ⇒‖ω−ˆℑjθ‖<ϵj,j=1,2,⋯,u. |
Then, the FP of ℑ aligns with that of ˆℑj(j=1,2,3,⋯,u,u≥4,u∈N).
Proof. Thanks to Theorem 2.1 (resp., Theorem 2.2), there are κj>0,j=1,2,3,⋯,u,u≥4,u∈N, with ∑uj=1κj∈(0,1] such that ˆℑ owns a unique FP ω∗∈Ω and the KI defined by ωm=ˆℑωm−1,m∈N converges to a unique FP of ℑ. Therefore, for every ϵj>0,j=1,2,3,⋯,u,u≥4,u∈N, there is M(j)∈N with m(j)≥M(j) such that
0<‖ω∗−ˆℑωm(j)‖≤ϵj, j=1,2,3,⋯,u,u≥4,u∈N. |
Using Hypothesis (H), for m(j)≥M(j), one has
‖ω∗−ℑjωm(j)‖≤ϵj, j=1,2,3,⋯,u,u≥4,u∈N. |
Put W=max{M(1),M(2),⋯,M(u)}. For m>W, we can write
‖ω∗−ˆℑωm‖=‖u∑j=1κj(ω∗−ℑjωm)‖≤u∑j=1‖κj(ω∗−ℑjωm)‖≤u∑j=1κjϵj≤u∑j=1κjϵ=ϵ. |
Hence, ‖ω∗−ℑjωm‖→0,j=1,2,3,⋯,u,u≥4,u∈N as m→∞ and for an arbitrary ϵ. Therefore, ω∗ is an FP of ℑj,j=1,2,3,⋯,u,u≥4,u∈N, and this aligns with the FP of ˆℑ.
Theorem 3.4. Let Ω be a BS and ℑ be an HEF-C (resp., HEF′-C). If the hypotheses (H1) or (H1) and (H) are satisfied, then ℑ admits the PPP Ξ.
Proof. The proof follows immediately from Theorem 3.3 and Lemma 3.1.
In this paper, we examine the necessary conditions for the u-fold AM and weakly enriched contractions to have equal sets of FPs. Additionally, we illustrate that an appropriate KI algorithm can effectively approximate an FP of a u-fold AM as well as the two enriched contractions. Also, we delve into the well-posedness, limit shadowing property, and UH stability of the u-fold AM. Furthermore, we establish necessary conditions that guarantee the PPP for each of the illustrated, strengthened contractions.
All authors contributed equally to the writing of this article. All authors have accepted responsibility for entire content of the manuscript and approved its submission.
The authors declare they have not used Artificial Intelligence (AI) tools in the creation of this article.
This study is supported via funding from Prince Sattam bin Abdulaziz University project number (PSAU/2024/R/1445).
The authors declare that they have no conflicts of interest.
This study is supported via funding from Prince Sattam bin Abdulaziz University project number (PSAU/2024/R/1445).
[1] |
S. Banach, Sur les opérations dans les ensembles abstraits et leur application aux équations intégrales, Fund. Math., 3 (1922), 133–181. https://doi.org/10.4064/fm-3-1-133-181 doi: 10.4064/fm-3-1-133-181
![]() |
[2] |
D. Chen, J. Li, Y. Zhang, A posterior contraction for Bayesian inverse problems in Banach spaces, Inverse Probl., 40 (2024), 045011. https://doi.org/10.1088/1361-6420/ad2a03 doi: 10.1088/1361-6420/ad2a03
![]() |
[3] |
Y. Zhang, B. Hofmann, Two new non-negativity preserving iterative regularization methods for ill-posed inverse problems, Inverse Probl. Imag., 15 (2021), 229–256. https://doi.org/10.3934/ipi.2020062 doi: 10.3934/ipi.2020062
![]() |
[4] |
G. Lin, X. Cheng, Y. Zhang, A parametric level set based collage method for an inverse problem in elliptic partial differential equations, J. Comput. Appl. Math., 340 (2018), 101–121. https://doi.org/10.1016/j.cam.2018.02.008 doi: 10.1016/j.cam.2018.02.008
![]() |
[5] |
A. Shcheglov, J. Li, C. Wang, A. Ilin, Y. Zhang, Reconstructing the absorption function in a quasi-linear sorption dynamic model via an iterative regularizing algorithm, Adv. Appl. Math. Mech., 16 (2024), 237–252. https://doi.org/ 10.4208/aamm.OA-2023-0020 doi: 10.4208/aamm.OA-2023-0020
![]() |
[6] |
T. M. Tuyen, H. A. Hammad, Effect of shrinking projection and CQ-methods on two inertial forward-backward algorithms for solving variational inclusion problems, Rend. Circ. Mat. Palermo II Ser., 70 (2021), 1669–1683. https://doi.org/10.1007/s12215-020-00581-8 doi: 10.1007/s12215-020-00581-8
![]() |
[7] |
H. A. Hammad, H. Ur Rehman, M. De la Sen, Advanced algorithms and common solutions to variational inequalities, Symmetry, 12 (2020), 1198. https://doi.org/10.3390/sym12071198 doi: 10.3390/sym12071198
![]() |
[8] |
H. A. Hammad, M. De la Sen, Analytical solution of Urysohn integral equations by fixed point technique in complex valued metric spaces, Mathematics, 7 (2019), 852. https://doi.org/10.3390/math7090852 doi: 10.3390/math7090852
![]() |
[9] |
H. A. Hammad, H. Aydi, M. De la Sen, Generalized dynamic process for an extended multi-valued F-contraction in metric-like spaces with applications, Alex. Eng. J., 59 (2020), 3817–3825. https://doi.org/10.1016/j.aej.2020.06.037 doi: 10.1016/j.aej.2020.06.037
![]() |
[10] | J. B. Baillon, On the asymptotic behavior of nonexpansive mappings and semigroups in Banach spaces, Houston J. Math., 4 (1978), 1–9. |
[11] | M. A. Krasnoselskii, Two remarks about the method of successive approximations, Uspekhi Mat. Nauk, 10 (1955), 123–127. |
[12] | H. Schaefer, Über die methode suksessiver approximation, Jber. Deutsch. Math. Verein, 59 (1957), 131–140. |
[13] |
M. Edelstein, A remark on a theorem of M. A. Krasnoselskii, Am. Math. Mon., 73 (1966), 509–510. https://doi.org/10.2307/2315474 doi: 10.2307/2315474
![]() |
[14] |
W. A. Kirk, On successive approximations for nonexpansive mappings in Banach spaces, Glasgow Math. J., 12 (1971), 6–9. https://doi.org/10.1017/S0017089500001063 doi: 10.1017/S0017089500001063
![]() |
[15] |
V. Berinde, M. Păcurar, Approximating fixed points of enriched contractions in Banach spaces, J. Fixed Point Theory Appl., 22 (2020), 38. https://doi.org/10.1007/s11784-020-0769-9 doi: 10.1007/s11784-020-0769-9
![]() |
[16] | R. M. T Bianchini, Su un problema di S. Reich riguardante la teoria dei punti fissi, Boll. Un. Mat. Ital., 5 (1972), 103–108. |
[17] | S. K. Chatterjea, Fixed point theorems compactes, Rend. Acad. Bulgare Sci., 25 (1972), 727–730. |
[18] | L. B. Cirić, Generalized contractions and fixed-point theorems, Publ. Inst. Math., 26 (1971), 19–26. |
[19] |
L. B. Cirić, A generalization of Banach's contraction principle, Proc. Am. Math. Soc., 45 (1974), 267–273. https://doi.org/10.2307/2040075 doi: 10.2307/2040075
![]() |
[20] | R. Kannan, Some results on fixed points, Bull. Cal. Math. Soc., 60 (1968), 71–76. |
[21] | M. S. Khan, On fixed point theorems, Math. Jpn., 23 (1979), 201–204. |
[22] |
S. Reich, Some remarks concerning contraction mappings, Can. Math. Bull., 14 (1971), 121–124. https://doi.org/10.4153/CMB-1971-024-9 doi: 10.4153/CMB-1971-024-9
![]() |
[23] |
H. A. Hammad, H. Aydi, Y. U. Gaba, Exciting fixed point results on a novel space with supportive applications, J. Funct. Space., 2021 (2021), 6613774. https://doi.org/10.1155/2021/6613774 doi: 10.1155/2021/6613774
![]() |
[24] |
H. A. Hammad, M. F. Bota, L. Guran, Wardowski's contraction and fixed point technique for solving systems of functional and integral equations, J. Funct. Space., 2021 (2021), 7017046. https://doi.org/10.1155/2021/7017046 doi: 10.1155/2021/7017046
![]() |
[25] |
H. A. Hammad, M. De la Sen, P. Agarwal, New coincidence point results for generalized graph-preserving multivalued mappings with applications, Adv. Differ. Equ., 2021 (2021), 334. https://doi.org/10.1186/s13662-021-03489-4 doi: 10.1186/s13662-021-03489-4
![]() |
[26] |
V. Berinde, Approximating fixed points of enriched nonexpansive mappings by Krasnoselskij iteration in Hilbert spaces, Carpathian J. Math., 35 (2019), 293–304. https://doi.org/10.37193/cjm.2019.03.04 doi: 10.37193/cjm.2019.03.04
![]() |
[27] |
V. Berinde, Approximating fixed points of enriched nonexpansive mappings in Banach spaces by using a retraction-displacement condition, Carpathian J. Math., 36 (2020), 27–34. https://doi.org/10.37193/CJM.2020.01.03 doi: 10.37193/CJM.2020.01.03
![]() |
[28] |
W. Nithiarayaphaks, W. Sintunavarat, On approximating fixed points of weak enriched contraction mappings via Kirk's iterative algorithm in Banach spaces, Carpathian J. Math., 39 (2023), 423–432. https://doi.org//10.37193/CJM.2023.02.07 doi: 10.37193/CJM.2023.02.07
![]() |
[29] |
V. Berinde, M. Păcurar, Kannan's fixed point approximation for solving split feasibility and variational inequality problms, J. Comput. Appl. Math., 386 (2021), 113217. https://doi.org/10.1016/j.cam.2020.113217 doi: 10.1016/j.cam.2020.113217
![]() |
[30] |
M. Abbas, R. Anjum, S. Riasat, Fixed point results of enriched interpolative Kannan type operators with applications, Appl. Gen. Topol., 23 (2022), 391–404. https://doi.org/10.4995/agt.2022.16701 doi: 10.4995/agt.2022.16701
![]() |
[31] |
V. Berinde, M. Păcurar, Approximating fixed points of enriched Chatterjea contractions by Krasnoselskij iterative algorithm in Banach spaces, J. Fixed Point Theory Appl., 23 (2021), 66. https://doi.org/10.1007/s11784-021-00904-x doi: 10.1007/s11784-021-00904-x
![]() |
[32] | V. Berinde, M. Păcurar, Fixed point theorems for enriched Ćirić-Reich-Rus contractions in Banach spaces and convex metric spaces, Carpathian J. Math., 37 (2021) 173–184. https://doi.org/10.37193/CJM.2021.02.03 |
[33] |
L. B. Ćirić, A generalization of Banach's contraction principle, Proc. Am. Math. Soc., 45 (1974), 267–273. https://doi.org/10.2307/2040075 doi: 10.2307/2040075
![]() |
1. | Kottakkaran Sooppy Nisar, Hasanen A. Hammad, Mohamed Elmursi, Corrigendum to "A new class of hybrid contractions with higher-order iterative Kirk's method for reckoning fixed points", 2024, 9, 2473-6988, 25934, 10.3934/math.20241266 |