Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 31 No. 5s (2024) 458 https://internationalpubls.com A Common Fixed Point Result in Menger Space *1 Ajay Kumar Chaudhary 1Department of Mathematics, Trichandra Multiple Campus Tribhuvan University, Kathmandu, Nepal * Corresponding author E-mail: akcsaurya81@gmail.com Article History: Received: 13-05-2024 Revised: 23-06-2024 Accepted: 10-07-2024 Abstract: By using compatibility condition type (P) in probabilistic metric space, establish common fixed point results for four self-mappings with control function in [0,1]. The result of Chaudhary et. al [5] is a particular case of this new result and it extends and generalizes other similar results in the literature. Keywords: Common fixed point, Menger Space, Compatible mappings, Compatible mappings of type (P). Mathematics Subject Classification: 47H10, 54H25 1. Introduction: Probabilistic metric space (PM space) is the idea of Karl’s Menger [11], a significant generalization of M. Frechet's [3] metric space. If PM space includes Menger inequality, then it is called Menger space. This space becomes active after the significant work of B. Schweizer and A. Skalar [13], [16] and V.M. Sehgal and A.T. Barucha Reid [14]. In 1991, S. N. Mishra [12] introduced the notion of compatible mapping in the Menger space and then so many researchers worked in this space, defining weakly compatible mappings, different compatible mappings types like (A), (K), (P) etc. see references [[2], [6], [7], [8], [9], [10], [14], [16]]. Recently, Chaudhary et. al [5-6] have given notions of compatible mapping of type (P) and weakly compatible mappings of type (P). This paper gives the new results in Menger space by using a control function Ο†: [0,1] β†’ [0,1] in four self-mappings and also deduces some consequences. 2. Preliminaries: Definition 2.1 [16]: If a function 𝑀: ℝ β†’ ℝ+ is (i) a non-decreasing function, (ii) left continuous and (iii) inf { 𝐹 (π‘₯): π‘₯ ∈ ℝ} = 0, sup{𝐹 (π‘₯): π‘₯ ∈ ℝ} = 1 then 𝑀 is said to be a distribution function. Definition 2.2 [4]: Let 𝑀: π‘Œ Γ— π‘Œ β†’ 𝐿 be a distribution function, 𝐿 be the set of all distribution functions and π‘Œ be a non-empty set. Then, a pair (π‘Œ, 𝑀) is said to be probabilistic metric space (abbreviated as pm-Space) if the distribution function 𝑀 (𝑝, π‘ž), where (𝑝, π‘ž) ∈ π‘Œ Γ— π‘Œ, also denoted by 𝑀𝑝,π‘ž satisfies following conditions: (M1) 𝑀𝑝,π‘ž(π‘₯) = 1 for every π‘₯ > 0 if and only if 𝑝 = π‘ž, Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 31 No. 5s (2024) 459 https://internationalpubls.com (M2) 𝑀𝑝,π‘ž(0) = 0 for every 𝑝, π‘ž ∈ 𝐾, (M3) 𝑀𝑝,π‘ž(π‘₯) = π‘€π‘ž,𝑝(π‘₯) for every 𝑝, π‘ž ∈ 𝐾, and (M4) 𝑀𝑝,π‘ž(π‘₯ + 𝑦) = 1 if and only if 𝑀𝑝,π‘Ÿ(π‘₯) = 1 and π‘€π‘Ÿ,π‘ž(𝑦) = 1. Here, 𝑀𝑝,π‘ž(π‘₯) represents the value of distribution function 𝑀𝑝,π‘ž π‘Žπ‘‘ π‘₯ ∈ ℝ. Definition 2.3 [4]: A function 𝑑 ∢ [0, 1] Γ— [0, 1] β†’ [0, 1] is referred to as a triangular norm (shortly t-norm) if it satisfies the following conditions: T1: 𝑑 (0, 0) = 0, T2: 𝑑 (π‘Ž, 1) = π‘Ž for all π‘Ž ∈ [0, 1], T3: 𝑑 (π‘Ž, 𝑏) = 𝑑 (𝑏, π‘Ž) for all π‘Ž, 𝑏 ∈ [0, 1], T4: 𝑖𝑓 π‘Ž ≀ 𝑐, 𝑏 ≀ 𝑑 then 𝑑 (π‘Ž, 𝑏) ≀ 𝑑 (𝑐, 𝑑), and T5: 𝑑 (𝑑 (π‘Ž, 𝑏), 𝑐) = 𝑑 (π‘Ž, 𝑑 (𝑏, 𝑐)), where π‘Ž, 𝑏, 𝑐, 𝑑 ∈ [0, 1]. Definition 2.4 [2]: A probabilistic metric space (π‘Œ, 𝑀) is said to be Menger space (π‘Œ, 𝑀, 𝑑), where t is a t-norm satisfying the following conditions: (M5) 𝑀𝑝,π‘ž(π‘₯ + 𝑦) β‰₯ 𝑑 (𝑀𝑝,π‘Ÿ(π‘₯), π‘€π‘Ÿ,π‘ž(𝑦)) for every 𝑝, π‘ž, π‘Ÿ ∈ π‘Œ and π‘₯, 𝑦 ∈ ℝ > 0. Definition 2.5 [2]: A mapping 𝐴: π‘Œ β†’ π‘Œ in Menger Space (𝐾, 𝐹, 𝑑), is said to be continuous at a point 𝑝 ∈ π‘Œ if for every ο₯ > 0 and  > 0, there exist ο₯1 > 0 and 1 > 0 such that if 𝑀𝑝,π‘ž (ο₯1) > 1 – 1 then 𝑀𝐴𝑝,π΄π‘ž(ο₯) > 1 βˆ’ . Definition 2.6 [2]: Let (π‘Œ, 𝑀, 𝑑) be a Menger space and 𝑑 be a continuous t-norm. Then, (a) A sequence {𝑦𝑛} in π‘Œ is said to converge to a point 𝑦 in π‘Œ if and only if for every ο₯ > 0 and  > 0, there exist an integer 𝑁 = 𝑁 (ο₯, ) such that 𝑀𝑦𝑛,𝑦(ο₯) > 1 βˆ’  for all 𝑛 β‰₯ 𝑁. In this case, we write, π‘™π‘–π‘š π‘›β†’βˆž 𝑦𝑛 = y. (b) A sequence {𝑦𝑛} in π‘Œ is said to be a Cauchy sequence if for every ο₯ > 0 and  > 0, there exists an integer 𝑁 = 𝑁 (ο₯, ) > 0 such that 𝑀𝑦𝑛,π‘¦π‘š (ο₯) > 1 βˆ’  for all π‘š, 𝑛 β‰₯ 𝑁. (c) A Menger space (π‘Œ, 𝑀, 𝑑) is said to be complete if every Cauchy sequence in π‘Œ converges to a point in π‘Œ. Definition 2.7:[7] Common fixed point of self-mapping functions 𝐴, 𝐡: π‘Œ β†’ π‘Œ is a point 𝑦 Î π‘Œ if 𝐴(𝑦) = 𝐡(𝑦) = 𝑦. Example 2.1: Let 𝐴, 𝐡: ℝ β†’ ℝ be functions such that 𝐴(𝑦) = 𝑦2 4 and 𝐡(𝑦) = 2𝑦 βˆ’ 4, then 𝑦 = 4 is a common fixed point of 𝐴 and 𝐡. Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 31 No. 5s (2024) 460 https://internationalpubls.com Definition 2.8:[12] Two mappings 𝐴, 𝐡: π‘Œ β†’ π‘Œ are said to be compatible mappings in Menger space (π‘Œ, 𝑀, 𝑑) iff π‘™π‘–π‘š π‘›β†’βˆž 𝐹𝐴𝐡π‘₯𝑛 , 𝐡𝐴π‘₯𝑛 (π‘₯) = 1 for all π‘₯ > 0, whenever sequence {π‘₯𝑛} in Y such that π‘™π‘–π‘š π‘›β†’βˆž 𝐴π‘₯𝑛 = π‘™π‘–π‘š π‘›β†’βˆž 𝐡π‘₯𝑛 = 𝑦 for some 𝑦 in π‘Œ. Definition 2.10: [15] Two mappings 𝐴, 𝐡: π‘Œ β†’ π‘Œ are said to be weakly compatible (or coincidently commuting) in Menger space (π‘Œ, 𝐹, 𝑑) if they commute at their coincidence points, that is, if 𝐴π‘₯ = 𝐡π‘₯ for some π‘₯ ∈ π‘Œ then 𝐴𝐡π‘₯ = 𝐡𝐴π‘₯. Definition 2.11:[6] Two mappings 𝐴, 𝐡: π‘Œ β†’ π‘Œ are said to be compatible mappings of type (𝑷) in Menger space (π‘Œ, 𝑀, 𝑑) iff π‘™π‘–π‘š π‘›β†’βˆž 𝑀𝐴𝐴π‘₯𝑛, 𝐡𝐡π‘₯𝑛 (π‘₯) = 1 βˆ€ π‘₯ > 0 whenever {π‘₯𝑛} is a sequence in π‘Œ such that π‘™π‘–π‘š π‘›β†’βˆž 𝐴π‘₯𝑛 = π‘™π‘–π‘š π‘›β†’βˆž 𝐡π‘₯𝑛 = 𝑦 for some 𝑦 𝑖𝑛 π‘Œ. Definition 2.12: [5]Two mappings 𝐴, 𝐡: π‘Œ β†’ π‘Œ are said to be weakly compatible mapping of type(𝑷) in Menger Space (π‘Œ, 𝑀, 𝑑) iff π‘™π‘–π‘š π‘›β†’βˆž 𝑀𝐴𝐴π‘₯𝑛, 𝐡𝐡π‘₯𝑛 (π‘₯) β‰₯ 𝑀𝐴π‘₯𝑛, 𝐡π‘₯𝑛 (π‘₯) βˆ€ π‘₯ > 0, whenever {π‘₯𝑛} is a sequence in π‘Œ such that π‘™π‘–π‘š π‘›β†’βˆž 𝐴π‘₯𝑛 = π‘™π‘–π‘š π‘›β†’βˆž 𝐡π‘₯𝑛 = 𝑦 for some 𝑦 𝑖𝑛 π‘Œ. Example 2.2: Let (π‘Œ, 𝑑) be metric space where π‘Œ = [0, 2]with usual metric 𝑑(π‘₯, 𝑦) = |π‘₯ βˆ’ 𝑦| and (π‘Œ, 𝑀) be PM space with 𝑀π‘₯,𝑦(𝑑) = {𝑒 𝑑(π‘₯,𝑦) 𝑑 , 𝑖𝑓 𝑑 > 0, 0, 𝑖𝑓 𝑑 = 0. for all π‘₯, 𝑦 ∈ π‘Œ. We define 𝐴 and 𝐡 as: 𝐴(π‘₯) = { 1 βˆ’ π‘₯, π‘“π‘œπ‘Ÿ π‘₯ ∈ [0, 1/2) 1 , π‘“π‘œπ‘Ÿ π‘₯ ∈ [ 1 2 , 2] and 𝐡(π‘₯) = { π‘₯, π‘“π‘œπ‘Ÿ π‘₯ ∈ [0, 1/2) 1, π‘“π‘œπ‘Ÿ π‘₯ ∈ [ 1 2 , 2] . Taking sequence {π‘₯𝑛} in π‘Œ where π‘₯𝑛 = 1 2 βˆ’ 1 𝑛 , 𝑛 ∈ 𝑁. Then, (𝐴, 𝐡) are weakly compatible mappings of type (𝑃) and it is neither compatible mappings of type (𝑃) nor compatible mappings. Theorem 2.1[2]: Let (π‘Œ, 𝑀, 𝑑) be Menger space with the continuous 𝑑 βˆ’ π‘›π‘œπ‘Ÿπ‘š 𝑑 and 𝐴: π‘Œ β†’ π‘Œ. Then, 𝐴 is continuous at a point 𝑦 ∈ π‘Œ if and only if for every sequence {𝑦𝑛} in π‘Œ converging to a point 𝑦, then sequence {𝐴𝑦𝑛} converges to the point 𝐴𝑦, i.e. if {𝑦𝑛} β†’ 𝑦 then it implies {𝐴𝑦𝑛} β†’ 𝐴𝑦. Proposition 2.1[9]: In Menger Space(π‘Œ, 𝑀, 𝑑), if 𝑑 (π‘˜, π‘˜) β‰₯ π‘˜ for all π‘˜ ∈ [0, 1] then 𝑑(π‘Ž, 𝑏) = π‘šπ‘–π‘› {π‘Ž, 𝑏} for all π‘Ž, 𝑏 ∈ [0, 1]. Lemma 2.1[15]: Let (π‘Œ, 𝑀, 𝑑) be a Menger space. If there exists π‘˜ ∈ (0, 1) such that for all 𝑝, π‘ž ∈ π‘Œ, 𝑀𝑝,π‘ž(π‘˜π‘₯) β‰₯ 𝑀𝑝,π‘ž(π‘₯) then 𝑝 = π‘ž. Proposition 2.2:[5] Let (π‘Œ, 𝑀, 𝑑) be a Menger space such that the t-norm 𝑑 is continuous and 𝑑 (π‘₯, π‘₯) β‰₯ π‘₯ for all π‘₯ ∈ [0, 1] and 𝐴, 𝐡: π‘Œ β†’ π‘Œ be continuous mappings. Then, 𝐴 and 𝐡 are weakly compatible mappings of type (P) if they are compatible mappings of type(𝑃). Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 31 No. 5s (2024) 461 https://internationalpubls.com Proposition 2.3: [5]Let (π‘Œ, 𝑀, 𝑑) be a Menger space such that the t-norm 𝑑 is continuous and 𝑑 (π‘₯, π‘₯) β‰₯ π‘₯ for all π‘₯ ∈ [0, 1] and 𝐴, 𝐡: π‘Œ β†’ π‘Œ be continuous mappings. Then, A and B are compatible mappings of type (𝑃) if they are weakly compatible mappings of type (𝑃). Proposition 2.4: [5]Let (π‘Œ, 𝑀, 𝑑) be a Menger space such that the t-norm 𝑑 is continuous and 𝑑 (π‘₯, π‘₯) β‰₯ π‘₯ for all π‘₯ ∈ [0, 1] and 𝐴, 𝐡: π‘Œ β†’ π‘Œ be mappings. If 𝐴 and 𝐡 are weakly compatible mappings of type (𝑃) and π΄π‘˜ = π΅π‘˜ for some π‘˜ ∈ 𝐾, then, π΄π΄π‘˜ = π΄π΅π‘˜ = π΅π΄π‘˜ = π΅π΅π‘˜. Proposition 2.5:[5] Let (π‘Œ, 𝑀, 𝑑) be a Menger space such that the t-norm 𝑑 is continuous and 𝑑 (π‘₯, π‘₯) β‰₯ π‘₯ for all π‘₯ ∈ [0, 1] and 𝐴, 𝐡: π‘Œ β†’ π‘Œ be mappings. Let 𝐴 and 𝐡 be weakly compatible mappings of type (𝑃) and π‘™π‘–π‘š π‘›β†’βˆž Aπ‘˜π‘› = π‘™π‘–π‘š π‘›β†’βˆž Bπ‘˜π‘› = k for some π‘˜ ∈ π‘Œ. Then We have, (𝑖) π‘™π‘–π‘š π‘›β†’βˆž BBπ‘˜π‘› = Ak 𝑖𝑓 𝐴 𝑖𝑠 π‘π‘œπ‘›π‘‘π‘–π‘›π‘’π‘œπ‘’π‘  π‘Žπ‘‘ π‘˜, (𝑖𝑖) π‘™π‘–π‘š π‘›β†’βˆž AAπ‘˜π‘› = Bk 𝑖𝑓 𝐡 𝑖𝑠 π‘π‘œπ‘›π‘‘π‘–π‘›π‘’π‘œπ‘’π‘  π‘Žπ‘‘ π‘˜, (𝑖𝑖𝑖) π΄π΅π‘˜ = π΅π΄π‘˜ π‘Žπ‘›π‘‘ π΄π‘˜ = π΅π‘˜ 𝑖𝑓 𝐴 π‘Žπ‘›π‘‘ 𝐡 π‘Žπ‘Ÿπ‘’ π‘π‘œπ‘›π‘‘π‘–π‘›π‘’π‘œπ‘’π‘  π‘Žπ‘‘ π‘˜. The following lemma needs to prove the main theorem: Lemma 2.2[15]: Let {π‘₯𝑛} be a sequence in Menger space (π‘Œ, 𝑀, 𝑑), where t is continuous 𝑑 βˆ’norm and 𝑑 (π‘₯, π‘₯) β‰₯ π‘₯ for all π‘₯ ∈ [0, 1]. If there exists a constant π‘˜ ∈ [0, 1] such that 𝑀π‘₯𝑛 , π‘₯𝑛+1 (π‘˜π‘₯) β‰₯ 𝑀π‘₯π‘›βˆ’1 , π‘₯𝑛 (π‘₯) for all π‘₯ > 0 and 𝑛 ∈ 𝑁, then {π‘₯𝑛} is a Cauchy sequence in π‘Œ. 3. Main Theorem: Now, we prove our main theorem for weakly compatible mappings of type (𝑃) in complete Menger space: Theorem 3.1: Let (π‘Œ, 𝑀, 𝑑) be a complete Menger space with 𝑑 (π‘₯, 𝑦) = π‘šπ‘–π‘› {π‘₯, 𝑦} for all π‘₯, 𝑦 ∈ [0, 1] π‘Žπ‘›π‘‘ 𝐴, 𝐡, 𝑆, 𝑇: π‘Œ β†’ π‘Œ be mappings such that (3.1.1) 𝐴 (π‘Œ) βŠ‚ 𝑇 (π‘Œ)π‘Žπ‘›π‘‘ 𝐡 (π‘Œ) βŠ‚ 𝑆 (π‘Œ), (3.1.2) the pairs (𝐴, 𝑆) and (𝐡, 𝑇) are weakly compatible mappings of type (𝑃), (3.1.3) One of 𝐴, 𝑆, 𝐡, 𝑇 be continuous, and (3.1.4) there exists a constant ΞΎ ∈ (0, 1) such that 𝑀(𝐴π‘₯, 𝐡𝑦, ΞΎ π‘ž) β‰₯ Ο†{min{𝑀(𝑆π‘₯, 𝐴π‘₯, π‘ž), 𝑀(𝑇𝑦, 𝐡𝑦, π‘ž), 𝑀( 𝑇𝑦, 𝐴π‘₯, π‘Ÿπ‘ž), 𝑀(𝑆π‘₯, 𝐡𝑦(2 βˆ’ π‘Ÿ)π‘ž, 𝑀(𝑆π‘₯, 𝑇𝑦, π‘ž)}} for all π‘₯, 𝑦 ∈ π‘Œ, π‘Ÿ ∈ (0, 2) and π‘ž > 0, π‘€β„Žπ‘’π‘Ÿπ‘’ Ο†: [0,1] β†’ [0,1] satisfies (i) Ο† is continuous and non-decreasing on [0,1] (ii) Ο†(n) > n for all n in [0,1] Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 31 No. 5s (2024) 462 https://internationalpubls.com noting that if Ο† ∈ Ξ¦, class of all mappings Ο†: [0,1] β†’ [0,1] then Ο†(0) = 0, Ο†(1) = 1 and Ο†(n) β‰₯ n for all n in [0,1]. Then, 𝐴, 𝐡, 𝑆, 𝑇 have a unique common fixed point in π‘Œ. Proof: Consider 𝑒0 ∈ π‘Œ. Since 𝐴(π‘Œ) βŠ‚ 𝑇 (π‘Œ), so there exists a point 𝑒1𝑖𝑛 π‘Œ such that 𝐴𝑒0 = 𝑇𝑒 1 = 𝑣0. Again, since 𝐡(π‘Œ) βŠ‚ 𝑆 (π‘Œ), so for 𝑒1, we may choose 𝑒2 in π‘Œ such that 𝐡𝑒1 = 𝑆𝑒2 = 𝑣1 and so on. And inductively, we may construct sequence {𝑒𝑛} and {𝑣𝑛} in π‘Œ such that 𝐴𝑒2𝑛 = 𝑇𝑒 2𝑛+1 = 𝑣2𝑛 , and 𝐡𝑒2𝑛+1 = 𝑆𝑒 2𝑛+2 = 𝑣2𝑛+1, π‘“π‘œπ‘Ÿ 𝑛 = 0, 1, 2, … Putting π‘₯ = 𝑒2𝑛 π‘Žπ‘›π‘‘ 𝑦 = 𝑒2𝑛+1 π‘“π‘œπ‘Ÿ π‘Žπ‘™π‘™ π‘ž > 0 π‘Žπ‘›π‘‘ π‘Ÿ = 1 βˆ’ 𝑝 π‘€π‘–π‘‘β„Ž 𝑝 πœ– (0, 1) 𝑖𝑛 (3. 1.4), we get 𝑀(𝐴𝑒2𝑛, 𝐡𝑒2𝑛+1, ΞΎ π‘ž) β‰₯ Ο†{min{𝑀(𝑆𝑒2𝑛, 𝐴𝑒2𝑛, π‘ž), 𝑀(𝑇𝑒2𝑛+1, 𝐡𝑒2𝑛+1, π‘ž), 𝑀(𝑇𝑒2𝑛+1, 𝐴𝑒2𝑛 , ((1 βˆ’ 𝑝))π‘ž), 𝑀(𝑆𝑒2𝑛, 𝐡𝑒2𝑛+1,((1 + 𝑝)π‘ž), 𝑀(𝑆𝑒2𝑛, 𝑇𝑒2𝑛+1, π‘ž)}} or, 𝑀(𝑣2𝑛, 𝑣2𝑛+1, ΞΎ π‘ž) β‰₯ Ο†{min{𝑀(𝑣2π‘›βˆ’1, 𝑣2𝑛, π‘ž), 𝑀(𝑣2𝑛, 𝑣2𝑛+1, π‘ž), 𝑀(𝑣2𝑛, 𝑣2𝑛 , ((1 βˆ’ 𝑝))π‘ž), 𝑀(𝑣2π‘›βˆ’1, 𝑣2𝑛+1,((1 + 𝑝)π‘ž), 𝑀(𝑣2π‘›βˆ’1, 𝑣2𝑛, π‘ž)}} β‰₯ Ο†{min{𝑀(𝑣2π‘›βˆ’1, 𝑣2𝑛, π‘ž), 𝑀(𝑣2𝑛, 𝑣2𝑛+1, π‘ž), 𝑀(𝑣2π‘›βˆ’1, 𝑣2𝑛+1,((1 + 𝑝)π‘ž), 𝑀(𝑣2π‘›βˆ’1, 𝑣2𝑛, π‘ž)}} β‰₯ Ο†{min{𝑀(𝑣2π‘›βˆ’1, 𝑣2𝑛, π‘ž), 𝑀(𝑣2𝑛, 𝑣2𝑛+1, π‘ž), 𝑀(𝑣2π‘›βˆ’1, 𝑣2𝑛, π‘ž), 𝑀(𝑣2𝑛, 𝑣2𝑛+1, π‘π‘ž), 𝑀(𝑣2π‘›βˆ’1, 𝑣2𝑛, π‘ž)}} β‰₯ Ο†{min{𝑀(𝑣2π‘›βˆ’1, 𝑣2𝑛, π‘ž), 𝑀(𝑣2𝑛, 𝑣2𝑛+1, π‘ž), 𝑀(𝑣2𝑛, 𝑣2𝑛+1, π‘π‘ž)}} As 𝑝 β†’ 1, we obtain 𝑀(𝑣2𝑛, 𝑣2𝑛+1, ΞΎ π‘ž) β‰₯ Ο†{min{𝑀(𝑣2π‘›βˆ’1, 𝑣2𝑛, π‘ž), 𝑀(𝑣2𝑛, 𝑣2𝑛+1, π‘ž), 𝑀(𝑣2𝑛, 𝑣2𝑛+1, π‘ž)}} β‰₯ Ο†{min{𝑀(𝑣2π‘›βˆ’1, 𝑣2𝑛, π‘ž), 𝑀(𝑣2𝑛, 𝑣2𝑛+1, π‘ž)} Or, 𝑀(𝑣2𝑛, 𝑣2𝑛+1, ΞΎ π‘ž) β‰₯ Ο†{𝑀(𝑣2π‘›βˆ’1, 𝑣2𝑛, π‘ž)} > 𝑀(𝑣2π‘›βˆ’1, 𝑣2𝑛, π‘ž), by property of Ο† Hence, we get 𝑀(𝑣2𝑛, 𝑣2𝑛+1, ΞΎ π‘ž) β‰₯ 𝑀(𝑣2π‘›βˆ’1, 𝑣2𝑛, π‘ž) Similarly, we obtain 𝑀(𝑣2𝑛+1, 𝑣2𝑛+2, ΞΎ π‘ž) β‰₯ 𝑀(𝑣2𝑛, 𝑣2𝑛+1, π‘ž) Therefore, for every 𝑛 ∈ 𝑁, 𝑀(𝑣𝑛, 𝑣𝑛+1, ΞΎ π‘ž) β‰₯ 𝑀(π‘£π‘›βˆ’1, 𝑣𝑛, π‘ž) So, using Lemma (2.2), {𝑣𝑛} is a Cauchy sequence in 𝐾. Since the Menger space (π‘Œ, 𝑀, 𝑑) is complete, so {𝑣𝑛} converges to a point 𝑧 in π‘Œ and consequently the subsequences {𝐴𝑒2𝑛 } , {𝐡𝑒2𝑛+1 }, {𝑆𝑒2𝑛 }, {𝑇𝑒2𝑛+1 }of {𝑣𝑛} also converges to 𝑧. Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 31 No. 5s (2024) 463 https://internationalpubls.com Now, suppose that 𝑇 is continuous. Then, since 𝐡 & 𝑇 are weakly compatible mappings of type (𝑃) then by proposition 2.5, 𝐡𝐡𝑒2𝑛+1 , 𝑇𝐡𝑒2𝑛+1 β†’ 𝑇𝑧 π‘Žπ‘  𝑛 β†’ ∞. Putting π‘₯ = 𝑒2𝑛 and 𝑦 = 𝐡𝑒2𝑛+1 in relation (3.1.4) , we get 𝑀(𝐴𝑒2𝑛, 𝐡𝐡𝑒2𝑛+1, ΞΎ π‘ž) β‰₯ Ο†{min{𝑀(𝑆𝑒2𝑛, 𝐴𝑒2𝑛, π‘ž), 𝑀(𝑇𝐡𝑒2𝑛+1, 𝐡𝐡𝑒2𝑛+1, π‘ž), 𝑀(𝑇𝐡𝑒2𝑛+1, 𝐴𝑒2𝑛 , π‘Ÿπ‘ž), 𝑀(𝑆𝑒2𝑛, 𝐡𝐡𝑒2𝑛+1,(2 βˆ’ π‘Ÿ)π‘ž), 𝑀(𝑆𝑒2𝑛, 𝑇𝐡𝑒2𝑛+1, π‘ž)}} Taking 𝑛 β†’ ∞, we have 𝑀(𝑧, 𝑇𝑧, ΞΎ π‘ž) β‰₯ Ο†{min{𝑀(𝑧, 𝑧, π‘ž), 𝑀(𝑇𝑧, 𝑇𝑧, π‘ž), 𝑀(𝑇𝑧, 𝑧, π‘Ÿπ‘ž), 𝑀(𝑧, 𝑇𝑧(2 βˆ’ π‘Ÿ)π‘ž), 𝑀(𝑧, 𝑇𝑧, π‘ž)}} Letting π‘Ÿ = 1 βˆ’ 𝑝 with 𝑝 ∈ (0, 1) then 𝑀(𝑧, 𝑇𝑧, ΞΎ π‘ž) β‰₯ Ο†{min{ 𝑀(𝑇𝑧, 𝑧, (1 βˆ’ 𝑝)π‘ž), 𝑀(𝑧, 𝑇𝑧(2 βˆ’ (1 βˆ’ 𝑝)π‘ž), 𝑀(𝑧, 𝑇𝑧, π‘ž)}} Or, 𝑀(𝑧, 𝑇𝑧, ΞΎ π‘ž) β‰₯ Ο†{min{ 𝑀(𝑇𝑧, 𝑧, (1 βˆ’ 𝑝)π‘ž), 𝑀(𝑧, 𝑇𝑧(1 + 𝑝)π‘ž), 𝑀(𝑧, 𝑇𝑧, π‘ž)}} β‰₯ Ο†{min{ 𝑀(𝑇𝑧, 𝑧, (1 βˆ’ 𝑝 + 1 + 𝑝)π‘ž), 𝑀(𝑧, 𝑇𝑧, π‘ž)}} β‰₯ Ο†{min{ 𝑀(𝑇𝑧, 𝑧, 2π‘ž), 𝑀(𝑧, 𝑇𝑧, π‘ž)}} β‰₯ Ο†{min{ 𝑀(𝑧, 𝑇𝑧, π‘ž)}} Therefore, 𝑀(𝑧, 𝑇𝑧, ΞΎ π‘ž) β‰₯ Ο†{𝑀(𝑧, 𝑇𝑧, π‘ž)} Or, 𝑀(𝑧, 𝑇𝑧, ΞΎ π‘ž) β‰₯ 𝑀(𝑧, 𝑇𝑧, π‘ž), by property of Ο† which implies 𝑧 = 𝑇𝑧 by Lemma 2.1. Similarly, replacing π‘₯ by 𝑒2𝑛 and 𝑦 𝑏𝑦 𝑧 in relation ( 3.1.4), we have 𝑀(𝐴𝑒2𝑛, 𝐡𝑧, ΞΎ π‘ž) β‰₯ Ο†{min{𝑀(𝑆𝑒2𝑛, 𝐴𝑒2𝑛, π‘ž), 𝑀(𝑇𝑧, 𝐡𝑧, π‘ž), 𝑀(𝑇𝑧, 𝐴𝑒2𝑛, π‘Ÿπ‘ž), 𝑀(𝑆𝑒2𝑛, 𝐡𝑧, (2 βˆ’ π‘Ÿ)π‘ž), 𝑀(𝑆𝑒2𝑛, 𝑇𝑧, π‘ž)}} Taking 𝑛 β†’ ∞, we get 𝑀(𝑧, 𝐡𝑧, ΞΎ π‘ž) β‰₯ Ο†{min{𝑀(𝑧, 𝑧, π‘ž), 𝑀(𝑧, 𝐡𝑧, π‘ž), 𝑀(𝑧, 𝑧, π‘Ÿπ‘ž), 𝑀(𝑧, 𝐡𝑧(2 βˆ’ π‘Ÿ)π‘ž), 𝑀(𝑧, 𝑧, π‘ž)}} β‰₯ Ο†{min{ 𝑀(𝑧, 𝐡𝑧, π‘ž), 𝑀(𝑧, 𝐡𝑧(2 βˆ’ (1 βˆ’ 𝑝))π‘ž)}} β‰₯ Ο†{min{ 𝑀(𝑧, 𝐡𝑧, π‘ž), 𝑀(𝑧, 𝐡𝑧(1 + 𝑝))π‘ž)}} β‰₯ Ο†{min{ 𝑀(𝑧, 𝐡𝑧, π‘ž), 𝑀(𝑧, 𝑧, π‘ž), 𝑀(𝑧, 𝐡𝑧, π‘π‘ž)}} β‰₯ Ο†{min{ 𝑀(𝑧, 𝐡𝑧, π‘ž), 𝑀(𝑧, 𝑧, π‘ž), 𝑀(𝑧, 𝐡𝑧, π‘π‘ž)}} β‰₯ Ο†{min{ 𝑀(𝑧, 𝐡𝑧, π‘ž), 𝑀(𝑧, 𝐡𝑧, π‘ž)}}, as 𝑝 β†’ 1 So that 𝑀(𝑧, 𝐡𝑧, ΞΎ π‘ž) β‰₯ Ο†{𝑀(𝑧, 𝐡𝑧, π‘ž)} Or, 𝑀(𝑧, 𝐡𝑧, ΞΎ π‘ž) β‰₯ 𝑀(𝑧, 𝐡𝑧, π‘ž), by property of Ο† which implies 𝑧 = 𝐡𝑧 by Lemma 2.1. Since, 𝐡(π‘Œ) βŠ‚ 𝑆 (π‘Œ), so there exists a point 𝑀 in π‘Œ such that 𝐡𝑧 = 𝑆𝑀 = 𝑧. By using relation ( 3.1.4) with π‘₯ = 𝑀, 𝑦 = 𝑧, we have Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 31 No. 5s (2024) 464 https://internationalpubls.com 𝑀(𝐴𝑀, 𝑧, ΞΎ π‘ž) β‰₯ Ο†{min{𝑀(𝑆𝑀, 𝐴𝑀, π‘ž), 𝑀(𝑇𝑧, 𝐡𝑧, π‘ž), 𝑀( 𝑇𝑧, 𝐴𝑧, π‘Ÿπ‘ž), 𝑀(𝑆𝑀, 𝐡𝑧(2 βˆ’ π‘Ÿ)π‘ž, 𝑀(𝑆𝑀, 𝑇𝑧, π‘ž)}} β‰₯ Ο†{min{𝑀(𝑧, 𝐴𝑀, π‘ž), 𝑀(𝑇𝑧, 𝑧, π‘ž), 𝑀( 𝑧, 𝐴𝑀, (1 βˆ’ 𝑝)π‘ž), 𝑀(𝑆𝑀, 𝑧(1 + 𝑝)π‘ž, 𝑀(𝑧, 𝑇𝑧, π‘ž)}} β‰₯ Ο†{min{𝑀(𝑧, 𝐴𝑀, π‘ž), 𝑀(𝑇𝑧, 𝑧, π‘ž), 𝑀( 𝐴𝑀, 𝑧, (1 βˆ’ 𝑝)π‘ž), 𝑀(𝑆𝑀, 𝑧(1 + 𝑝)π‘ž, 𝑀(𝑧, 𝑇𝑧, π‘ž)}} β‰₯ Ο†{min{𝑀(𝑧, 𝐴𝑀, π‘ž), 𝑀(𝑧, 𝑧, π‘ž), 𝑀( 𝐴𝑀, 𝑆𝑀, (1 βˆ’ 𝑝 + 1 + 𝑝)π‘ž)}} β‰₯ Ο†{min{𝑀(𝑧, 𝐴𝑀, π‘ž), 𝑀( 𝐴𝑀, 𝑧, 2π‘ž) }} Therefore, 𝑀(𝐴𝑀, 𝑧, ΞΎ π‘ž) β‰₯ Ο†{𝑀(𝑧, 𝐴𝑀, π‘ž)} Or, 𝑀(𝐴𝑀, 𝑧, ΞΎ π‘ž) β‰₯ 𝑀(𝑧, 𝐴𝑀, π‘ž), by property of Ο† which implies 𝐴𝑀 = 𝑧 by Lemma 2.1. Again, since 𝐴 π‘Žπ‘›π‘‘ 𝑆 are weakly compatible mappings of type (𝑃) and 𝐴𝑀 = 𝑆𝑀 = 𝑧, by proposition 2.4, we have for every ο₯ > 0 1 = 𝑀(𝐴𝐴𝑀, 𝑆𝑆𝑀, πœ–) β‰₯ 𝑀(𝐴𝑀, 𝑆𝑀, πœ–) Hence 𝐴𝑀 = 𝐴𝐴𝑀 = 𝑆𝑆𝑀 = 𝑆𝑀 Finally, by relation (3.1.4) with π‘₯ = 𝑧, 𝑦 = 𝐡𝑧 = 𝑧, we have 𝑀(𝐴𝑧, 𝑧, ΞΎ π‘ž) = 𝑀(𝐴𝑧, 𝐡𝑧, ΞΎ π‘ž) β‰₯ Ο†{min{𝑀(𝑆𝑧, 𝐴𝑧, π‘ž), 𝑀(𝑇𝑧, 𝑧, π‘ž), 𝑀( 𝑇𝑧, 𝐴𝑧, π‘Ÿπ‘ž), 𝑀(𝑆𝑧, 𝑧(2 βˆ’ π‘Ÿ)π‘ž, 𝑀(𝑆𝑧, 𝑇𝑧, π‘ž)} β‰₯ Ο†{min{𝑀(𝐴𝑧, 𝐴𝑧, π‘ž), 𝑀(𝑧, 𝑧, π‘ž), 𝑀( 𝑧, 𝐴𝑧, π‘Ÿπ‘ž), 𝑀(𝐴𝑧, 𝑧(2 βˆ’ π‘Ÿ)π‘ž, 𝑀(𝐴𝑧, 𝑧, π‘ž)} β‰₯ Ο†{min{ 𝑀( 𝐴𝑧, 𝑧, π‘Ÿπ‘ž), 𝑀(𝑧, 𝐴𝑧(2 βˆ’ π‘Ÿ)π‘ž, 𝑀(𝐴𝑧, 𝑧, π‘ž)} β‰₯ Ο†{min{ 𝑀(𝐴𝑧, 𝐴𝑧, π‘Ÿπ‘ž + (2 βˆ’ π‘Ÿ)π‘ž, 𝑀(𝐴𝑧, 𝑧, π‘ž)} β‰₯ Ο†{min{ 𝑀(𝐴𝑧, 𝑧, π‘ž)} β‰₯ Ο†{𝑀(𝐴𝑧, 𝑧, π‘ž)} Or, 𝑀(𝐴𝑧, 𝑧, ΞΎ π‘ž) β‰₯ 𝑀(𝐴𝑧, 𝑧, π‘ž), by property of Ο†  𝐴𝑧 = 𝑧, by Lemma 2.1. Hence, 𝐴𝑧 = 𝐡𝑧 = 𝑆𝑧 = 𝑇𝑧 = 𝑧 . That is, 𝑧 is a common fixed point of given mappings 𝐴, 𝐡, 𝑆 & 𝑇. Uniqueness: Suppose 𝑧1 is another point in π‘Œ such that 𝑧1 = 𝐴𝑧1 = 𝐡𝑧1 = 𝑆𝑧1 = 𝑇𝑧1. Then, putting π‘₯ = 𝑧 π‘Žπ‘›π‘‘ 𝑦 = 𝑧1, π‘Ÿ = 1 in (3.1.4), we get 𝑀(𝐴𝑧, 𝐡𝑧1, ΞΎ π‘ž) = 𝑀(𝑧, 𝑧1, ΞΎ π‘ž) β‰₯ Ο†{min{𝑀(𝑆𝑧, 𝐴𝑧, π‘ž), 𝑀(𝑇𝑧1, 𝐡𝑧1, π‘ž), 𝑀( 𝑇𝑧1, 𝐴𝑧, π‘ž), 𝑀(𝑆𝑧, 𝑇𝑧1, π‘ž)} Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 31 No. 5s (2024) 465 https://internationalpubls.com Or, 𝑀(𝑧, 𝑧1, ΞΎ π‘ž) β‰₯ Ο†{min{𝑀(𝑧, 𝑧1, π‘ž), 𝑀( 𝑧, 𝑧, π‘ž)} Or, 𝑀(𝑧, 𝑧1, ΞΎ π‘ž) β‰₯ Ο†{𝑀(𝑧, 𝑧1, π‘ž)} 𝑀(𝑧, 𝑧1, ΞΎ π‘ž) β‰₯ 𝑀(𝑧, 𝑧1, π‘ž), by property of Ο†  𝑧 = 𝑧1, by Lemma 2.1. Hence, 𝑧 = 𝐴𝑧 = 𝐡𝑧 = 𝑆𝑧 = 𝑇𝑧, and 𝑧 is a unique common fixed point for A, B, S, and T in π‘Œ. This completes the proof. 4. Conclusion: In conclusion, the result of Chaudhary et. al. [5] is a particular case of this theorem. Also, this theorem may apply to consequences results in metric space in four self-mappings and generalizes and improves other similar results in the literature. 5. 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