EUROPEAN JOURNAL OF PURE AND APPLIED MATHEMATICS Vol. 17, No. 4, 2024, 2492-2504 ISSN 1307-5543 – ejpam.com Published by New York Business Global Common Fixed Point of Generalized Berinde Type Contraction and an Application Habes Alsamir1,∗, Haitham Qawaqneh2, Gawhara Al-Musannef3, Roshdi Khalil4 1 Finance and Banking Department, Business Administration College, Dar Aluloom University, Riyadh, Saudi Arabia 2 Department of Mathematics,Faculty of Science and Information Technology, Al-Zaytoonah University of Jordan, Amman 11733, Jordan. 3 Faculty of Business Studies, Arab Open University, Jeddah, Saudi Arabia 4 Department of Mathematics, Faculty of Science, The University of Jordan, Amman, 11942, Jordan Abstract. In this paper, we introduce λ(s,φ,ψ,L)-generalized Berinde type contraction and obtain some common fixed point results for such class of contractions the setting of triangular α-admissible mappings with respect to η in the framework of b-metric spaces. Our results generalize and extend some theorems in the literature. An example is given to support our result. 2020 Mathematics Subject Classifications: 47H10, 54H25 Key Words and Phrases: Triangular α-admissible mappings with respect to η, common fixed point, b−metric spaces 1. Introduction and preliminaries The most important tools in fixed point theory is Banach contraction principle. A lot of authors have extended or generalized this contraction and proved the existence of fixed and common fixed point theorems for single valued and multi-valued mappings and some applica- tion (see [3–6, 11, 14–18, 21–23]). The concept of the b-metric space was introduced by Czerwik [12] and he also obtained some fixed-point theorems of contractive mappings in b-metric space. Since then, this notion has been used by many authors to obtain various fixed point theorems. Roshan et al. in [18] used the notion of almost generalized contractive mappings in ordered complete b-metric spaces and established some fixed and common fixed point results. The main goal of this section is to present some definitions and properties of b-metric spaces: Definition 1.1. ([12]) Let 𭟋 be a nonempty set. A mapping Λb : 𭟋×𭟋 → [0,+∞) is said to be a b-metric if the following three conditions hold for all u, v ∈ 𭟋 : (Λ1) Λ(u, v) = 0 ⇒ u = v; (Λ2) Λ(u, v) = Λ(v, u); (Λ3) Λ(u, v) ≤ s[Λ(u,w) + Λ(w, v)]. In this case, the pair (𭟋,Λb) is called a b-metric space. Example 1.2. Let (𭟋,Λb) be a metric space and let β > 1, ϱ ≥ 0 and µ > 0. For u, v ∈ 𭟋, set Λb(u, v) = ϱΛb(u, v)+µΛb(u, v) β. Then (𭟋,Λb) is a b-metric space with the parameter s = 2β−1 and not a metric space on 𭟋. ∗Corresponding author. DOI: https://doi.org/10.29020/nybg.ejpam.v17i4.5388 Email addresses: habes@dau.edu.sa (H. Alsamir), h.alqawaqneh@zuj.edu.jo (H. Qawaqneh), G.almusannef@arabou.edu.sa (J.M. Al-musannef), roshdi@ju.edu.jo (R. Khalil) https://www.ejpam.com 2492 Copyright: © 2024 The Author(s). (CC BY-NC 4.0) H. Alsamir et al. / Eur. J. Pure Appl. Math, 17 (4) (2024), 2492-2504 2493 Example 1.3. Let 𭟋 be the set of Lebesgue measurable functions on [0,1] such that ∫ 1 0 | p(u) |2< +∞. Define Λb(u, v) = ∫ 1 0 | p(u)− q(u) |2 d(u). Then Λb satisfies the following properties: (i) Λb(u, v) = 0 ⇔ u = v (ii) Λb(u, v) = Λb(v, u), for all u, v ∈ 𭟋 (iii) Λb(u, v) ≤ 2[Λb(u,w) + Λb(w, v)], for all u,w, v ∈ 𭟋. Definition 1.4. ([20]) Let (𭟋,Λb) be a b-metric space. Then a sequence {un} in 𭟋 is called: (i) b-convergent if and only if there exists v ∈ 𭟋 such that Λb(un, u) → 0, as n → +∞. In this case, we write limn→+∞ un = u. (2) b-Cauchy if and only if Λb(un, um) = 0 as n,m→ ∞. Proposition 1.5. ([11]) In b-metric space (𭟋,Λb) the following assertions holds: (1) A b-convergent sequence has a unique limit, (2) Each b-convergent is b-Cauchy, (3) In general, a b-metric is not continuous. Proposition 1.6. ([11]) The b-metric space (𭟋,Λb) is complete if every Cauchy sequence in 𭟋 b-converges. Qawagneh et al. [19] introduced the notion of triangular α-admissible with respect to η for p and q on a set 𭟋 as the following: Definition 1.7. ([20])Let p, q : 𭟋 → 𭟋 be two mappings and α, η : 𭟋×𭟋 → R be two functions such that the following assertions hold: (i) if α(u, v) ≥ η(u, v), then α(pu, qv) ≥ η(pu, qv), and α(pqu, qpv) ≥ η(pqu, qpv), (ii) if α(u, h) ≥ η(u, h), and α(h, v) ≥ η(h, v), then α(u, v) ≥ η(u, v), Lemma 1.8. ([22]) Let p, q : 𭟋 → 𭟋 be two mappings and α, η : 𭟋×𭟋 → R be two functions such that the pair (p, q) is triangular α-admissible with respect to η. Assume that there exist u0 ∈ 𭟋 such that α(u0, pu0) ≥ η(u0, pu0). Define a sequence {un} in 𭟋 by pu2n = u2n+1 and qu2n+1 = u2n+2. Then α(un, um) ≥ η(un, um) for all m,n ∈ N with n < m. Berinde [[6],[7],[8],[9],[10]] presented many interesting fixed-point results for various types of contraction mappings. In [8] and [9], he defined the almost contraction map as follows. Definition 1.9. Let (𭟋,Λ) be a metric space. A map p : 𭟋 → 𭟋 is called an almost contraction if there exist a constant λ ∈ [0, 1) and some L ≥ 0 such that: Λ(pu, pv) ≤ λΛ(u, v) + LΛ(v, pu) for all u, v ∈ 𭟋. Let Φ the set of all increasing and continuous functions φ : [0,+∞) → [0,+∞) and let ∆ be the set of all lower semi-continuous functions ψ : [0,+∞) → [0,+∞) with ψ(b) = b if and only if b = 0. H. Alsamir et al. / Eur. J. Pure Appl. Math, 17 (4) (2024), 2492-2504 2494 2. An λ(s,φ,ψ,L)- generalized Berinde type contraction mapping Now, we will present λ(s,φ,ϕ,L)- generalized Berinde type contraction mapping prove our main result for such class of contractions in the framework of b-metric spaces. Definition 2.1. Let (𭟋,Λb) be a b-metric space with parameter s ≥ 1 and p, q : 𭟋 → 𭟋 be a two mappings. Then we consider that the pair (p, q) is λ(s,φ,ϕ,L)-generalized Berinde type contraction mapping if there exists α, η : 𭟋×𭟋 → R be two mappings, φ ∈ Ω, ϕ ∈ Φ, λ ∈ [0, 1), L ≥ 0 such that φ ( s2Λb(pu, qv) ) ≤ λ [φ (MΛb (u, v))− ϕ (MΛb (u, v)) + LNΛb (u, v)] , (2.1) holds for all u, v ∈ 𭟋, where MΛb (u, v) = max { Λb(u, v),Λb(u, pu),Λb(v, qv), Λb(u, qv) + Λb(pu, v) 2s[1 + Λb(pu, v)] } , and NΛb (u, v) = min {Λb(u, v),Λb(u, pu),Λb(v, qv),Λb(v, pu)} . Now we begin with our first result. Theorem 2.2. Let (𭟋,Λb) be a complete b-metric space with the constant s ≥ 1, and (p, q) be two self-mappings on 𭟋. Suppose that α, η : 𭟋 × 𭟋 → R are two functions. Assume that the following conditions hold: (i) λ(s,φ,ϕ,L)-Berinde type contraction mapping; (ii) the pair (p, q) is triangular α-admissible with respect to η; (iii) there exists u0 ∈ 𭟋 such that α(u0, pu0) ≥ η(u0, pu0), (iv) p and q are continuous mappings. Then, p and q have a common fixed point in 𭟋. Proof. Let u0 ∈ 𭟋 such that α(u0, pu0) ≥ η(u0, pu0). We define a sequence {un} ⊂ 𭟋 such that u2n+1 = pu2n and u2n+2 = qu2n+1 for all n ∈ N. If ∃ an n∗ such that un∗+1 = un∗ for some n∗ ∈ N, then it is very easy to show that p and q have a common fixed point, which completes the proof. Since the pair (p, q) is triangular α-admissible with respect to η, then α(u1, u2) = α(pu0, qu1) ≥ η(pu0, qu1) = η(u1, u2) and α(u2, u1) = α(pu1, qu0) ≥ η(pu1, qu0) = η(u2, u1). One more time by using triangular α-admissible with respect to η, we get α(u2, u3) = α(pu1, qu2) ≥ η(pu1, qu2) = η(u2, u3) and α(u3, u2) = α(pu2, qu1) ≥ η(pu2, qu1) = η(u3, u2). By repeating the above steps for n−times, we obtain the following α(un, un+1) ≥ η(un, un+1) and α(un+1, un) ≥ η(un+1, un). By Lemma 1.8, we have α(u2n, u2n+1) ≥ η(u2n, u2n+1) for all n ∈ N and since (p, q) is λ(s,φ,ψ,L)-generalized Berinde type contraction mapping, we get φ(Λb(u2n+1, u2n+2)) ≤ φ(s2Λb(pu2n, qu2n+1) ≤ λ[φ(MΛb (u2n, u2n+1))− ϕ(MΛb (u2n, u2n+1)) + LNΛb (u2n, u2n+1)](2.2) H. Alsamir et al. / Eur. J. Pure Appl. Math, 17 (4) (2024), 2492-2504 2495 for all n ∈ N, where MΛb (u2n, u2n+1) = max {Λb(u2n, u2n+1),Λb(u2n, pu2n),Λb(u2n+1, qu2n+1), Λb(u2n, qu2n+1) + Λb(pu2n, u2n+1) 2s(1 + Λb(pu2n, u2n+1)) } = max {Λb(u2n, u2n+1),Λb(u2n, u2n+1),Λb(u2n+1, u2n+2), Λb(u2n, u2n+2) + Λb(u2n+1, u2n+1) 2s(1 + Λb(u2n+1, u2n+1)) } = max { Λb(u2n, u2n+1),Λb(u2n+1, u2n+2), Λb(u2n, u2n+2) 2s } and NΛb (u2n, u2n+1) = min{Λb(u2n, u2n+1),Λb(u2n, pu2n),Λb(u2n+1, qu2n+1),Λb(u2n+1, pu2n)} i.e., NΛb (u2n, u2n+1) = 0 (2.3) Since Λb(u2n, u2n+2) 2s ≤ s[Λb(u2n, u2n+1) + Λb(u2n+1, u2n+2)] 2s ≤ Λb(u2n, u2n+1) + Λb(u2n+1, u2n+2) 2 ≤ max{Λb(u2n, u2n+1),Λb(u2n+1, u2n+2)}, we get MΛb (u2n, u2n+1)) ≤ max{Λb(u2n, u2n+1),Λb(u2n+1, u2n+2)}. (2.4) Taking (2.3) and (2.4) into account,(2.2) yields φ(Λb(u2n+1, u2n+2)) ≤ λ [φ (max{Λb(u2n, u2n+1),Λb(u2n+1, u2n+2)}) −λϕ (max{Λb(u2n, u2n+1),Λb(u2n+1, u2n+2)})] < φ (max{Λb(u2n, u2n+1),Λb(u2n+1, u2n+2)}) − ϕ (max{Λb(u2n, u2n+1),Λb(u2n+1, u2n+2)}) . Now, we will show that Λb(u2n+1, u2n+2) ≤ Λb(u2n, u2n+1). Arguing by contradiction, we assume Λb(u2n+1, u2n+2) > Λb(u2n, u2n+1). Therefore, we have two cases. Case 1: MΛb (u2n, u2n+1) = Λb(u2n, u2n+1). Then φ(Λb(u2n+1, u2n+2) < φ(Λb(u2n, u2n+1))− ϕ(Λb(u2n, u2n+1)) < φ(Λb(u2n, u2n+1)) Since φ is increasing, we have Λb(u2n+1, u2n+2) < Λb(u2n, u2n+1). which is a contradiction. Case 2: MΛb (u2n, u2n+1) = Λb(u2n+1, u2n+2). Then φ(Λb(u2n+1, u2n+2) < φ(Λb(u2n+1, u2n+2))− ϕ(Λb(u2n+1, u2n+2)) < φ(Λb(u2n+1, u2n+2)) Since φ is increasing, we have Λb(u2n+1, u2n+2) < Λb(u2n+1, u2n+2). Which is a impossible. Hence from the above we have Λb(u2n+1, u2n+2) ≤ Λb(u2n, u2n+1) By similar way, we can prove that Λb(u2n, u2n+1) ≤ Λb(u2n−1, u2n). So, we conclude that Λb(un, un+1) ≤ Λb(un−1, un). that is, the sequence Λb(un+1, un+1) is a decreasing sequence and bounded below for all n ∈ N. Therefore there ∃ ω ≥ 0 such that lim n→∞ Λb(un, un+1) = ω. H. Alsamir et al. / Eur. J. Pure Appl. Math, 17 (4) (2024), 2492-2504 2496 We want to prove that ω = 0. Now, we have φ(ω) ≤ λ[φ(ω)− ϕ(ω)] < φ(ω)− ϕ(ω) < φ(ω) which is a contradiction. Hence lim n→∞ Λb(un, un+1) = 0. (2.5) Now, we want to prove that {un} is a Cauchy sequence by Lemma 1.8, ∃ ε > 0 and two subsequences {umi} and {uni} of {un} with mi > ni > i such that Λb(uni , umi) ≥ ε Λb(uni−1, umi) < ε. By using the triangular inequality, we have ε ≤ Λb(uni , umi) ≤ Λb(uni , uni−1) + sΛb(uni−1, umi) < s[Λb(uni , uni−1) + ε] (2.6) Letting i→ +∞ on both sides of (2.6) and using (2.5), we obtain ε ≤ lim n→+∞ Λb(uni , umi) < sε. (2.7) From triangular inequality, we have Λb(uni , umi) ≤ s[Λb(uni , uni+1) + Λb(uni+1, umi)], (2.8) and Λb(uni+1, umi) ≤ s[Λb(uni+1, uni) + Λb(uni , umi)]. (2.9) By taking upper limit as i→ +∞ in (2.8) and applying (2.5) , (2.7) , we get ε ≤ lim sup i→+∞ Λb(uni , umi) ≤ s ( lim sup +i→+∞ Λb(uni+1, umi) ) . Again, by letting the upper limit as i→ +∞ in (2.9), we have lim sup i→+∞ Λb(uni+1, umi) ≤ s ( lim sup i→+∞ Λb(uni , umi) ) ≤ s.sε = s2ε. Thus ε s ≤ lim sup i→+∞ Λb(uni+1, umi) ≤ s2ε. (2.10) Similarly, ε s ≤ lim sup i→+∞ Λb(uni , umi+1) ≤ s2ε. (2.11) By using the triangular inequality, we get Λb(uni+1, umi) ≤ s[Λb(uni+1, umi+1) + Λb(umi+1, umi)]. (2.12) On letting i→ +∞ in (2.12) and using the inequalities (2.5) , (2.10) , we get ε s2 ≤ lim sup i→+∞ Λb(uni+1, umi+1). (2.13) H. Alsamir et al. / Eur. J. Pure Appl. Math, 17 (4) (2024), 2492-2504 2497 By following the above methods, we find lim sup i→+∞ Λb(uni+1, umi+1) ≤ s3ε. (2.14) From (2.13) and (2.14), we obtain ε s ≤ lim sup i→+∞ Λb(uni+1, umi+1) ≤ s3ε. (2.15) By Lemma 1.8, we have α(uni+1, umi+1) ≥ η(uni+1, umi+1). Thus, we have φ(Λb(uni+1, umi+1)) ≤ φ(s2Λb(uni+1, umi+1)) ≤ λ [φ (MΛb (uni , umi))− ϕ (MΛb (uni , umi)) + L (NΛb (uni , umi))] = [λφ (MΛb (uni , umi))− λϕ (MΛb (uni , umi)) + λL (NΛb (uni , umi))] , where MΛb (uni , umi) = max{Λb(uni , umi),Λb(uni , puni),Λb(umi , qumi), Λb(uni , qumi) + Λb(puni , umi) 2s(1 + Λb(puni , umi)) }. NΛb (uni , umi) = min {Λb(uni , umi),Λb(uni , puni),Λb(umi , qumi),Λb(umi , puni)} = min {Λb(uni , umi),Λb(uni , uni+1),Λb(umi , umi+1),Λb(umi , uni+1)}(2.16) Taking the limit as i → +∞ in the above two expressions and using (2.5),(2.7) ,(2.10) and (2.11), we obtain ε = max{ε, ε s + ε s 2s } ≤ lim sup i→+∞ Λb(uni , umi) ≤ max{sε, s 2ε+ s2ε 2s } = sε. lim sup i→+∞ NΛb (uni , umi) = 0. From (2.13), we obtain φ(sε) ≤ φ(s2 ε s2 ) ≤ φ(s2 lim sup i→+∞ φ(Λb(uni+1, umi+1)) ≤ λ[φ(lim sup i→+∞ MΛb (uni , umi)− ϕ(lim inf i→+∞ MΛb (uni , umi) ≤ λ[φ(sε)− ϕ(sε)] ≤ λ(φ(sε))− λ(ϕ(sε)) < λφ(sε) which leads to a contradiction. Thus {un} is a Cauchy sequence. Since 𭟋 is an complete b- metric space and α(uni+1, umi+1) ≥ η(uni+1, umi+1) for all n ∈ N0, there exists θ such that limn→+∞ un = θ. If p is continuous, we have pθ = limn→+∞ pu2n = limn→+∞ u2n+1 = θ. From Condition (2.2), we have: φ(Λb(θ, qθ)) ≤ φ(s2Λb(θ, θ)) ≤ λ[(φ(MΛb (θ, θ))− ϕ(MΛb (θ, θ)) + LNΛb (θ, θ)] H. Alsamir et al. / Eur. J. Pure Appl. Math, 17 (4) (2024), 2492-2504 2498 for all n ∈ N, where MΛb (θ, θ) = max{Λb(θ, θ),Λb(θ, pθ),Λb(θ, qθ), Λb(θ, qθ) + Λb(pθ, θ) 2s(1 + Λb(pθ, θ)) } = Λb(θ, qθ) and NΛb (θ, θ) = min{Λb(θ, θ),Λb(θ, pθ),Λb(θ, qθ),Λb(θ, qθ)} = 0. By using the properties of φ and ϕ, we have φ(Λb(θ, qθ)) = φ(s2Λb(pθ, qθ)) ≤ λ[(φ(MΛb (θ, qθ))− ϕ(MΛb (θ, θ))] = λ[(φ(Λb(θ, qθ))− ϕ(Λb(θ, qθ))] < λ(φ(Λb(θ, qθ))). Hence, θ = qθ is θ is the common fixed of p and q. If q is continuous, then, by a similar way of the above, we can prove that p and q have a common fixed point. Theorem 2.3. Let (𭟋,Λb) be a complete b-metric space with the constant s ≥ 1, and (p, q) be two self-mappings on 𭟋. Suppose that α, η : 𭟋 × 𭟋 → R are two functions. Assume that the following conditions hold: (i) λ(s,φ,ϕ,L)-Berinde type contraction mapping; (ii) the pair (p, q) is triangular α-admissible with respect to η; (iii) If ∃ u0 ∈ 𭟋 such that α(u0, pu0) ≥ η(u0, pu0), (iv) if {un} is a sequence in 𭟋 such that α(un, un+1) ≥ η(un, un+1), for all n ∈ N and un → θ as n→ ∞, then ∃ a subsequence {uni} of {un} such that α(uni , u∗) ≥ η(uni , u∗), for all i ∈ N. Then, p and q have a common fixed point in 𭟋. Proof. Following similar arguments as in the proof of Theorem 2.2, we obtain a sequence {un} is defined by u2n+1 = pu2n and u2n+2 = pu2n+1 for all n ∈ N converging to u∗ ∈ 𭟋 such that α(u2n, u2n+1) ≥ η(u2n, u2n+1) for all n ∈ N. By (iv), there exist a subsequence {uni} of {un} such that α(uni , u∗) ≥ η(uni , u∗), for all i ∈ N. Therefore φ(Λb(u2ni+1, qu∗)) ≤ φ(s2Λb(pu2ni , qu∗) ≤ λ[(φ(MΛb (u2ni , u∗))− ϕ(MΛb (u2ni , u∗)) + LNΛb (u2ni , u∗)] (2.17) for all n ∈ N, where MΛb (u2ni , u∗)) = max{Λb(u2ni , u∗),Λb(u2ni , pu2ni),Λb(u∗, qu∗), Λb(u2ni , qu∗) + Λb(pu2ni , u∗) 2s(1 + Λb(pu2ni , u∗)) } = max{Λb(u2n, u∗),Λb(u2n, u2ni+1),Λb(u∗, qu∗), Λb(u2ni , qu∗) + Λb(u2ni+1, u∗) 2s(1 + Λb(u2ni+1, u∗)) } and NΛb (u2ni , u∗) = min{Λb(u2ni , u∗),Λb(u2ni , pu2ni),Λb(u∗, qu∗),Λb(u∗, pu2ni)} = min{Λb(u2ni , u∗),Λb(u2ni , u2ni+1),Λb(u∗, qu∗),Λb(u∗, u2ni+1)}. Since lim sup i→∞ Λb(u2ni , qu∗) + Λb(u2ni+1, u∗) 2s(1 + Λb(u2ni+1, u∗)) ≤ Λb(u∗, qu∗) 2 . H. Alsamir et al. / Eur. J. Pure Appl. Math, 17 (4) (2024), 2492-2504 2499 By taking i→ ∞ in (2.18) and (2.18) using (2.5), we deduce that lim sup i→∞ MΛb (u2ni , u∗)) = Λb(u∗, qu∗) and lim sup i→∞ NΛb (u2ni , u∗)) = 0. From (2.17)and taking in account () and (), we have φ(Λb(u∗, qu∗)) ≤ λ[φ(Λb(u∗, qu∗))− ϕ(Λb(u∗, qu∗)))] (2.18) < λφ(Λb(u∗, qu∗))− λϕ(Λb(u∗, qu∗)). (2.19) By definition of φ and ϕ, we have a contradiction. Hence Λb(u∗, qu∗) = 0, i.e., qu∗ = u∗. By the same way we can prove that pu∗ = u∗. Definition 2.4. Let (𭟋,Λb) be a b-metric space with parameter s ≥ 1, p, q : 𭟋 → 𭟋 and α, η : 𭟋 × 𭟋 → R be two functions. Let φ ∈ Ω, ϕ ∈ Φ and λ ∈ [0, 1). Then the pair (p, q) is called λ(s, φ, ϕ)-contraction mapping of type (B) if α(u, v) ≥ η(u, v), then φ ( s2Λb(pu, qv) ) ≤ λ [φ (MΛb (u, v))− ϕ (MΛb (u, v))] , (2.20) where λ ∈ [0, 1) φ ∈ Ω, ϕ ∈ Φ and MΛb (u, v) = max { Λb(u, v),Λb(u, pu),Λb(v, qv), Λb(u, qv) + Λb(pu, v) 2s[1 + Λb(pu, v)] } . . The proof of the followings two theorems follows from Theorem 2.2 and Theorem 2.3 by putting L = 0. Theorem 2.5. Let (𭟋,Λb) be a complete b-metric space with the constant s ≥ 1, and (p, q) be two self-mappings on 𭟋. Suppose that α, η : 𭟋 × 𭟋 → R are two functions. Assume that the following conditions hold: (i) λ(s, φ, ϕ)- contraction type (B) mapping; (ii) the pair (p, q) is triangular α-admissible with respect to η; (iii) There exists u0 ∈ 𭟋 such that α(u0, pu0) ≥ η(u0, pu0), (iv) p and q are continuous mappings. Then, p and q have a common fixed point in 𭟋. Theorem 2.6. Let (𭟋,Λb) be a complete b-metric space with the constant s ≥ 1, and (p, q) be two self-mappings on 𭟋. Suppose that α, η : 𭟋 × 𭟋 → R are two functions. Assume that the following conditions hold: (i) λ(s, φ, ϕ)-contraction mapping type (B); (ii) the pair (p, q) is triangular α-admissible with respect to η; (iii) If ∃ u0 ∈ 𭟋 such that α(u0, pu0) ≥ η(u0, pu0), (iv) if {un} is a sequence in 𭟋 such that α(un, un+1) ≥ η(un, un+1), for all n ∈ N and un → θ as n→ ∞, then there exist a subsequence {uni of {un} such that α(uni , u∗) ≥ η(uni , u∗), for all i ∈ N. Then, p and q have a common fixed point in 𭟋. The following corollaries are consequences of Theorem 2.2 and Theorem 2.3. H. Alsamir et al. / Eur. J. Pure Appl. Math, 17 (4) (2024), 2492-2504 2500 Corollary 2.7. Let (𭟋,Λb) be a complete b-metric space with the constant s ≥ 1, and p be a self-mapping on 𭟋. Suppose that α, η : 𭟋×𭟋 → R are two functions. Suppose that the following conditions hold: (i) If α(u, v) ≥ η(u, v) ⇒ φ ( s2Λb(pu, pv) ) ≤ λ [φ (MΛb (u, v))− ϕ (MΛb (u, v)) + (NΛb (u, v))] , (2.21) (ii)p is triangular α-admissible with respect to η; (iii) If ∃ u0 ∈ 𭟋 such that α(u0, pu0) ≥ η(u0, pu0), (iv) p is a continuous mappings. Then, p has a fixed point in 𭟋. Proof. The conclusion follows from Theorem 2.2 by taking q = p. Corollary 2.8. Let (𭟋,Λb) be a complete b-metric space with the constant s ≥ 1, and p be a self-mapping on 𭟋. Suppose that α : 𭟋×𭟋 → R are two functions. Assume that the following conditions hold: (i) If α(u, v) ≥ 1 ⇒ φ ( s2Λb(pu, pv) ) ≤ λ [φ (MΛb (u, v))− ϕ (MΛb (u, v)) + (NΛb (u, v))] , (2.22) (ii)p is triangular α-admissible with respect to η; (iii) There exists u0 ∈ 𭟋 such that α(u0, pu0) ≥ 1, (iv) p is a continuous mappings. Then, p has a fixed point in 𭟋. Proof. The proof follows Corollary 2.7 by defining η : 𭟋×𭟋 → R via η(u, v) = 1. Remark 2.9. Since a b-metric space is a metric space when s = 1, so our Theorems can be seen as a generalizations and extensions of several comparable results in metric spaces and b-metric spaces. The following example illustrates the above result. Example 2.10. Let 𭟋 = {1, 2, 3, 4}. Define Λb : 𭟋×𭟋 → [0,+∞) as follows: Λb(u, v) = Λb(v, u) = 0 if u ̸= v, u = v Λb(u, v) = Λb(v, u) = 2 if u = 1, v = 2 Λb(u, v) = Λb(v, u) = 1 if u = 1, v = 3 Λb(u, v) = Λb(v, u) = 10 if u, v = 1, 2, 3, v = 4 Define φ(t) = et, ϕ(t) = et 2+et , λ = 1 2 , L = 2 and define the mappings p, q : 𭟋 → 𭟋 by p1 = p2 = p3 = 1, p4 = 3 q1 = 2, q2 = q3 = q4 = 1. It is obvious that (𭟋,Λb) is a complete b-metric space with the constant s = 2. We show that the condition (2.1) is true. We put φ ( s2Λb(pu, qv) ) = A,φ(MΛb (u, v)) = B,ϕ(MΛb (u, v)) = C and NΛb (u, v) = D. Then we have the following cases: H. Alsamir et al. / Eur. J. Pure Appl. Math, 17 (4) (2024), 2492-2504 2501 Table 1: The possible values of u, v Λb(u, v) A λ[B − C +D] A ≤ λ[B − C +D] ✓ Λb(1, 1) ≈ 2.72 ≈ 3.30 2.72 < 3.30 ✓ Λb(2, 2) 1 ≈ 3.30 1 < 3.30 ✓ Λb(3, 3) 1 ≈ 1.07 1 < 1.07 ✓ Λb(4, 4) ≈ 54.60 ≈ 11012.73 54.60 < 11012.73 ✓ Λb(1, 2) 1 ≈ 3.30 1 < 3.30 ✓ Λb(1, 3) 1 ≈ 1.07 1 < 1.07 ✓ Λb(1, 4) 1 ≈ 11012.73 1 < 11012.73 ✓ Λb(2, 3) 1 ≈ 3.30 1 < 3.30 ✓ Λb(2, 4) 1 ≈ 11012.73 1 < 11012.73 ✓ Λb(3, 4) 1 ≈ 11012.73 1 < 11012.73 ✓ λ[B − C +D] A A = λ[B − C +D] A ≤ λ[B − C +D] Λb(1, 1) Λb(2, 2)Λb(3, 3) Λb(4, 4) Figure 1. Satisfing the enquality A ≤ λ[B − C +D] Thus, all the conditions of Theorem 2.1 are satisfied and hence p and q have a common fixed point. Indeed, 1 is a common fixed point of p and q. 3. Application Fixed point theorem has numerous applications, such as fractional differential equations ([1], [2], [13]), the significance of these types of equations is their utilization in modeling in many subjects. In this section, we utilize our results to demonstrate the existence and uniqueness of the Fredholm type integral equation. Now, Consider the set 𭟋 = C([0, 1], (−∞,∞)) and the following Fredholm type integral equa- tion: ṕ(t) = ∫ 1 0 S(t, s, ṕ(t)) ds, for t, s ∈ [0, 1], (3.1) where S(t, s, ṕ(t)) is a continuous function on [0, 1]× [0, 1] → (−∞,∞). Now, define Λb : 𭟋×𭟋 → C and (p, q) 7→| ṕ(t)− q(t) | . Note that (𭟋,Λb) is a complete b-metric space, where the parameter s = 2. Theorem 3.1. Suppose that for all p, q ∈ 𭟋 (1) | S(t, s, ṕ(t))− S(t, s, q(t)) |≤ |ṕ(t)−q(t)| 2 . REFERENCES 2502 (2) | S(t, s, ∫ 1 0 S(t, s, ṕ(t)) ds) − S(t, s, q ∫ 1 0 S(t, s, q(t)) ds) |≤| S(t, s, ṕ(t)) − S(t, s, q(t)) | for all t, s. Then the integral equation 3.1 has a unique solution. Proof. Let ṕ(t) : 𭟋 → 𭟋 defined by ṕ(t) = ∫ 1 0 S(t, s, ṕ(t)) ds, then Λb(ṕ, q) =| ṕ(t)− q(t) | . Now we have Λb(ṕ(t), q(t)) = | ṕ(t)− q(t) | = | S(t, s, ∫ 1 0 S(t, s, ṕ(t)) ds)− S(t, s, q ∫ 1 0 S(t, s, q(t)) ds) | ≤ | S(t, s, ṕ(t))− S(t, s, q(t)) | ≤ | ṕ(t)− q(t) | 2 ≤ 1 2 Λb(ṕ(t), q(t)) = λ [φ (MΛb (ṕ(t), q(t)))− ϕ (MΛb (ṕ(t), q(t)))] , where φ(t) = t and ϕ(t) = t 2 . Also the parameter s < 3. Hence, all the hypotheses of Theorem 2.2, are fulfilled and then the equation 3.1 has a unique solution. 4. Conclusion We have demonstrated the existence and uniqueness of a fixed point for self-mapping in b- metric spaces under diverse nonlinear mappings with continuous control functions. Also, we show an application of our results to Fredholm-type integral equations. Additionally, we would like to bring the researchers consideration to the following question. 4.1. Question Under what conditions we will get the same results for self-mapping in partial b-metric spaces? 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