PARADIGMA BARU PENDIDIKAN MATEMATIKA DAN APLIKASI ONLINE INTERNET PEMBELAJARAN CONTACT: Ahmad Khairul Umam akumam@billfath.ac.id Department of Mathematics, Universitas Billfath, Lamongan, East Java 62261 The article can be accessed here. https://doi.org/10.15642/mantik.2022.8.2.105-112 Existence and Uniqueness of Fixed Points in Cone Metric Spaces for 𝝎-distance Ahmad Khairul Umam1, Nihaya Alivia C. Dewi1, Pukky Tetralian B. Ngastiti1 1Universitas Billfath, Lamongan, Indonesia Article history: Received Nov 19, 2021 Revised May 14, 2022 Accepted Dec 31, 2022 Kata Kunci: Titik Tetap, Metrik Cone, Jarak-πœ” Abstrak. Di dalam penelitian ini, fungsi jarak yang digunakan adalah fungsi jarak-πœ”. Beberapa teorema, pembuktian teorema, dan contoh tentang ruang metrik cone dibahas pada penelitian ini. Jika diberikan ruang metrik cone lengkap dengan fungsi jarak-πœ”, cone normal 𝑃 di 𝑋, fungsi kontraksi 𝑓: 𝑋 β†’ 𝑋 dengan bentuk πœ”(𝑓(π‘₯), 𝑓(𝑦)) β‰Ό π›Όπœ”(π‘₯, 𝑦) + 𝛽[πœ”(π‘₯, 𝑓(π‘₯) + πœ”(𝑦, 𝑓(𝑦)] + 𝛾[πœ”(π‘₯, 𝑓(𝑦) + πœ”(𝑦, 𝑓(π‘₯)] untuk setiap π‘₯, 𝑦 ∈ 𝑋, dan 𝛼, 𝛽, 𝛾 adalah bilangan real tak negatif dimana 𝛼 + 2𝛽 + 2𝛾 < 1, maka fungsi 𝑓 memiliki titik tetap tunggal di 𝑋. Keywords: Fixed Point, Cone Metric, πœ”-distance Abstract. In this study, the distance function used is the distance function-πœ”. Several theorems, proof of theorem, and example of cone metric space are discussed in this study. If given a complete cone metric space with distance function, the cone is normal at contraction function 𝑓: 𝑋 β†’ 𝑋 with πœ”(𝑓(π‘₯), 𝑓(𝑦)) β‰Ό π›Όπœ”(π‘₯, 𝑦) + 𝛽[πœ”(π‘₯, 𝑓(π‘₯) + πœ”(𝑦, 𝑓(𝑦)] + 𝛾[πœ”(π‘₯, 𝑓(𝑦) + πœ”(𝑦, 𝑓(π‘₯)] for every π‘₯, 𝑦 ∈ 𝑋, and 𝛼, 𝛽, 𝛾 is a non-negative real number where 𝛼 + 2𝛽 + 2𝛾 < 1, then function 𝑓 has unique fixed point at 𝑋. How to cite: A. K. Umam, N. H. A. Dewi, and P. T. B. Ngastiti, β€œExistence and Uniqueness of Fixed Points in Cone Metric Spaces for 𝝎-distance”, J. Mat. Mantik, vol. 8, no. 2, pp. 105-112, December 2022. Jurnal Matematika MANTIK Vol. 8, No. 2, December 2022, pp. 105-112 ISSN: 2527-3159 (print) 2527-3167 (online) mailto:akumam@billfath.ac.id http://u.lipi.go.id/1458103791 Jurnal Matematika MANTIK Vol. 8, No. 2, December 2022, pp. 105-112 106 1. Introduction Fixed point has many useful for solving linear equation, ordinary differential equation, partial differential equation, intergral equation. The famous fixed point theorem is Banach fixed point theorem. According to [1], the Banach fixed point guarantee the existence and uniqueness of fixed point for function in complete space and contractive function. In this paper we discuss some fixed point theorems in cone metric space with πœ”- distance. According to [2], cone metric space is generalization of metric space. Range of cone metric space is Banach space. We use real Banach space and πœ”-distance for mertic. According to [3], a πœ”-distance is a function in metric spaces with three condition: symmetry, lower semicontinuous function, and relationship πœ”-distance with metric itself. 2. Preliminaries Definition 1. [4] Let 𝑉 is non-empty set with addition and scalar (real number) multiplication operation. Addition operation: οΏ½Μ…οΏ½, οΏ½Μ…οΏ½ ∈ 𝑉, οΏ½Μ…οΏ½ + οΏ½Μ…οΏ½ ∈ 𝑉; and scalar multiplication operation: π‘˜ ∈ ℝ, οΏ½Μ…οΏ½ ∈ 𝑉, π‘˜οΏ½Μ…οΏ½ ∈ 𝑉. 𝑉 is called vector space if satisfy V1. βˆ€οΏ½Μ…οΏ½, οΏ½Μ…οΏ½ ∈ 𝑉, οΏ½Μ…οΏ½ + οΏ½Μ…οΏ½ ∈ 𝑉; V2. βˆ€οΏ½Μ…οΏ½, οΏ½Μ…οΏ½, οΏ½Μ…οΏ½ ∈ 𝑉, (οΏ½Μ…οΏ½ + οΏ½Μ…οΏ½) + οΏ½Μ…οΏ½ = οΏ½Μ…οΏ½ + (οΏ½Μ…οΏ½ + οΏ½Μ…οΏ½); V3. βˆƒ0Μ… ∈ 𝑉, βˆ€οΏ½Μ…οΏ½ ∈ 𝑉, 0Μ… + οΏ½Μ…οΏ½ = οΏ½Μ…οΏ½ + 0Μ… = οΏ½Μ…οΏ½; V4. βˆ€οΏ½Μ…οΏ½ ∈ 𝑉, βˆƒ βˆ’ οΏ½Μ…οΏ½ ∈ 𝑉, οΏ½Μ…οΏ½ + (βˆ’οΏ½Μ…οΏ½) = βˆ’οΏ½Μ…οΏ½ + οΏ½Μ…οΏ½ = 0Μ…; V5. βˆ€οΏ½Μ…οΏ½, οΏ½Μ…οΏ½ ∈ 𝑉, οΏ½Μ…οΏ½ + οΏ½Μ…οΏ½ = οΏ½Μ…οΏ½ + οΏ½Μ…οΏ½; V6. βˆ€π‘˜ ∈ ℝ, βˆ€οΏ½Μ…οΏ½ ∈ 𝑉, π‘˜οΏ½Μ…οΏ½ ∈ 𝑉; V7. βˆ€π‘˜ ∈ ℝ, βˆ€οΏ½Μ…οΏ½, οΏ½Μ…οΏ½ ∈ 𝑉, π‘˜(οΏ½Μ…οΏ½ + οΏ½Μ…οΏ½) = π‘˜οΏ½Μ…οΏ½ + π‘˜οΏ½Μ…οΏ½; V8. βˆ€π‘˜, β„Ž ∈ ℝ, βˆ€οΏ½Μ…οΏ½ ∈ 𝑉, (π‘˜ + β„Ž)οΏ½Μ…οΏ½ = π‘˜οΏ½Μ…οΏ½ + β„ŽοΏ½Μ…οΏ½; V9. βˆ€π‘˜, β„Ž ∈ ℝ, βˆ€οΏ½Μ…οΏ½ ∈ 𝑉, π‘˜(β„ŽοΏ½Μ…οΏ½) = π‘˜β„Ž(οΏ½Μ…οΏ½); V10. βˆƒ1 ∈ ℝ, βˆ€οΏ½Μ…οΏ½ ∈ 𝑉, 1. οΏ½Μ…οΏ½ = οΏ½Μ…οΏ½. Definition 2. [5] Let 𝑉 is vector space over the field 𝔽. Function β€–βˆ™β€–: 𝑉 β†’ ℝ is called norm of 𝑉 if satisfy N1. β€–π‘₯β€– β‰₯ 0 for all π‘₯ ∈ 𝑉; N2. If π‘₯ ∈ 𝑉 dan β€–π‘₯β€– = 0 then π‘₯ = 0; N3. ‖𝛼π‘₯β€– = |𝛼|β€–π‘₯β€– for all π‘₯ ∈ 𝑉 and 𝛼 ∈ 𝔽; N4. β€–π‘₯ + 𝑦‖ ≀ β€–π‘₯β€– + ‖𝑦‖ for all π‘₯, 𝑦 ∈ 𝑉. A normed space is a vector space 𝑉 together with a norm β€–βˆ™β€–. Definition 3. [6] All complete normed vector space is called Banach space. Definition 4. [7] A metric on a set 𝑋 is a function 𝑑: 𝑋 Γ— 𝑋 β†’ ℝ that satisfies the following properties: M1. 𝑑(π‘₯, 𝑦) β‰₯ 0 for all π‘₯, 𝑦 ∈ 𝑋. (positivity) M2. 𝑑(π‘₯, 𝑦) = 0 if and only if π‘₯ = 𝑦. (definiteness) M3. 𝑑(π‘₯, 𝑦) = 𝑑(𝑦, π‘₯) for all π‘₯, 𝑦 ∈ 𝑋. (symmetry) M4. 𝑑(π‘₯, 𝑦) ≀ 𝑑(π‘₯, 𝑧) + 𝑑(𝑧, 𝑦) for all π‘₯, 𝑦, 𝑧 ∈ 𝑋. (triangle inequality) A metric space (𝑋, 𝑑) is a set 𝑋 together with a metric 𝑑 on 𝑋. Definition 5. [8] Let 𝔼 is real Banach space and 𝑃 a subset of 𝔼. A set 𝑃 is called a cone if only if: i 𝑃 is closed, nonempty, and 𝑃 β‰  0; ii π‘Žπ‘₯ + 𝑏𝑦 ∈ 𝑃 for all π‘₯, 𝑦 ∈ 𝑃 dan π‘Ž, 𝑏 ∈ ℝ+ βˆͺ {0}; Ahmad Khairul Umam, Nihaya Alivia C. Dewi, and Pukky Tetralian B. N. Existence and Uniqueness of Fixed Points in Cone Metric Spaces for 𝝎-distance 107 iii 𝑃 ∩ (βˆ’π‘ƒ) = 0. Further, if 𝑃 βŠ† 𝔼 is cone, then we define partial ordering β€œβ‰Όβ€ with respect to 𝑃 by π‘₯ β‰Ό 𝑦 if only if 𝑦 βˆ’ π‘₯ ∈ 𝑃. And then π‘₯ < 𝑦 is interpreted π‘₯ β‰Ό 𝑦 and π‘₯ β‰  𝑦. Whereas π‘₯ < 𝑦 is interpreted 𝑦 βˆ’ π‘₯ ∈ 𝑖𝑛𝑑 𝑃 (interior of 𝑃). Definition 6. [9] The cone 𝑃 is called normal if there is a number 𝑀 > 0 such that for all π‘₯, 𝑦 ∈ 𝔼, 0 ≀ π‘₯ ≀ 𝑦 implies β€–π‘₯β€– ≀ 𝑀‖𝑦‖. (1) The least positive 𝑀 satisfying (1) is called the normal constant of 𝑃. Definition 7. [2] A cone metric on non-empty set 𝑋 is a function 𝑑: 𝑋 Γ— 𝑋 β†’ 𝔼 that satisfies the following properties: C1. 0 < 𝑑(π‘₯, 𝑦) for all π‘₯, 𝑦 ∈ 𝑋 and 𝑑(π‘₯, 𝑦) = 0 if only if π‘₯ = 𝑦; C2. 𝑑(π‘₯, 𝑦) = 𝑑(𝑦, π‘₯) for all π‘₯, 𝑦 ∈ 𝑋; C3. 𝑑(π‘₯, 𝑦) ≀ 𝑑(π‘₯, 𝑧) + 𝑑(𝑧, 𝑦) for all π‘₯, 𝑦 dan 𝑧 ∈ 𝑋. A cone metric spaces (𝑋, 𝑑) is a set 𝑋 together with a metric 𝑑 on 𝑋. Definition 8. [10] Let (𝑋, 𝑑) be a cone metric space, 〈π‘₯𝑛 βŒͺ be a sequence in 𝑋. If for any 𝑐 ∈ 𝔼 with 0 < 𝑐, there is 𝑁 such that for all 𝑛 > 𝑁, 𝑑(π‘₯, π‘₯𝑛 ) < 𝑐, then 〈π‘₯𝑛 βŒͺ is called a convergent sequence to a point π‘₯ ∈ 𝑋. Definition 9. [2] Let (𝑋, 𝑑) be a cone metric space, 〈π‘₯𝑛 βŒͺ be a sequence in 𝑋. If for any 𝑐 ∈ 𝔼 with 0 < 𝑐, there is 𝑁 such that for all π‘š, 𝑛 > 𝑁, 𝑑(π‘₯𝑛 , π‘₯π‘š ) < 𝑐, then 〈π‘₯𝑛 βŒͺ is called a Cauchy sequence in 𝑋. Definition 10. [11] Let (𝑋, 𝑑) be a cone metric space, 〈π‘₯𝑛 βŒͺ be a sequence in 𝑋. (𝑋, 𝑑) is a complete cone metric space if every Cauchy sequence is convergent. Definition 11. [12] A function πœ“ from a metric space (𝑋, 𝑑) to ℝ is called lower semicontinuous if for every 𝑦 ∈ 𝑋, π‘™π‘–π‘š π‘₯→𝑦 𝑖𝑛𝑓 πœ“(π‘₯) β‰₯ πœ“(𝑦). Example 1. Let a function 𝑓(π‘₯) = { 2, π‘₯ > 2 1, π‘₯ ≀ 2 . The function 𝑓(π‘₯) is lower semicontinuous at π‘₯ = 2. 𝑦 2 1 -1 0 1 2 3 4 π‘₯ Figure 1. Example of lower semicontinuous function Definition 12. [13] Let (𝑋, 𝑑) be a metric space and a function 𝑓: 𝑋 β†’ 𝑋. A point π‘₯ ∈ 𝑋 is called a fixed point of function 𝑓 if π‘₯ = 𝑓(π‘₯). Definition 13. [14] Let metric space (𝑋, 𝑑). Function 𝑓: 𝑋 β†’ 𝑋 is said contraction function if there is a real number 𝑐 where 0 ≀ 𝑐 < 1 such that: 𝑑(𝑓(π‘₯), 𝑓(𝑦)) ≀ 𝑐𝑑(π‘₯, 𝑦), βˆ€π‘₯, 𝑦 ∈ 𝑋. Theorem 1. [15] (Banach’s Fixed Point). Let (𝑋, 𝑑) is complete metric space. If function 𝑓: 𝑋 β†’ 𝑋 is contraction function in 𝑋, then function 𝑓 has unique fixed point. Jurnal Matematika MANTIK Vol. 8, No. 2, December 2022, pp. 105-112 108 Defintion 14. [16] A function πœ”: 𝑋 Γ— 𝑋 β†’ [0, ∞) is a πœ”-distance on 𝑋 if it satisfies the following conditions for any π‘₯, 𝑦, 𝑧 ∈ 𝑋: Ο‰1. πœ”(π‘₯, 𝑧) ≀ πœ”(π‘₯, 𝑦) + πœ”(𝑦, 𝑧) Ο‰2. The function πœ”(π‘₯,β‹…): 𝑋 β†’ [0, ∞) is lower semicontinuous Ο‰3. For any > 0, there exists 𝛿 > 0 such that πœ”(𝑧, π‘₯) ≀ 𝛿 and πœ”(𝑧, 𝑦) ≀ 𝛿 imply 𝑑(π‘₯, 𝑦) ≀ . Of course, the metric 𝑑 is a πœ”-distance on 𝑋. 3. Result and Discussion Theorem 2. Let complete cone metric space (𝑋, 𝑑) with πœ”-distance. Let normal cone 𝑃 in 𝑋 and function 𝑓: 𝑋 β†’ 𝑋 that satisfy πœ”(𝑓(π‘₯), 𝑓(𝑦)) β‰Ό π›Όπœ”(π‘₯, 𝑦) + 𝛽[πœ”(π‘₯, 𝑓(π‘₯)) + πœ”(𝑦, 𝑓(𝑦))] +𝛾[πœ”(π‘₯, 𝑓(𝑦)) + πœ”(𝑦, 𝑓(π‘₯))] (2) for all π‘₯, 𝑦 ∈ 𝑋 where 𝛼, 𝛽, 𝛾 are non-negative real numbers such that 𝛼 + 2𝛽 + 2𝛾 < 1, then 𝑓 has unique fixed point in 𝑋. Proof: Let a sequence 〈π‘₯𝑛 βŒͺ in cone metric space (𝑋, 𝑑). A sequence 〈π‘₯𝑛 βŒͺ satisfies this property: π‘₯𝑛 = 𝑓(π‘₯π‘›βˆ’1) = 𝑓(𝑓(π‘₯π‘›βˆ’2)) = 𝑓 2(π‘₯π‘›βˆ’2) = β‹― = 𝑓 𝑛(π‘₯0) where 𝑛 ∈ β„•. According (2), we get πœ”(𝑓(π‘₯0), 𝑓 2(π‘₯0)) β‰Ό π›Όπœ”(π‘₯0, 𝑓(π‘₯0)) + 𝛽[πœ”(π‘₯0, 𝑓(π‘₯0)) + πœ”(𝑓(π‘₯0), 𝑓 2(π‘₯0))] +𝛾[πœ”(π‘₯0, 𝑓 2(π‘₯0)) + πœ”(𝑓(π‘₯0), 𝑓(π‘₯0))] = π›Όπœ”(π‘₯0, 𝑓(π‘₯0)) + π›½πœ”(π‘₯0, 𝑓(π‘₯0)) + π›½πœ”(𝑓(π‘₯0), 𝑓 2(π‘₯0)) +π›Ύπœ”(π‘₯0, 𝑓 2(π‘₯0)) + π›Ύπœ”(𝑓(π‘₯0), 𝑓(π‘₯0)) = π›Όπœ”(π‘₯0, 𝑓(π‘₯0)) + π›½πœ”(π‘₯0, 𝑓(π‘₯0)) + π›½πœ”(𝑓(π‘₯0), 𝑓 2(π‘₯0)) +π›Ύπœ”(π‘₯0, 𝑓 2(π‘₯0)) + 0 = π›Όπœ”(π‘₯0, 𝑓(π‘₯0)) + π›½πœ”(π‘₯0, 𝑓(π‘₯0)) + π›½πœ”(𝑓(π‘₯0), 𝑓 2(π‘₯0)) +π›Ύπœ”(π‘₯0, 𝑓 2(π‘₯0)). (3) We use triangle inequality and we get πœ”(π‘₯0, 𝑓 2(π‘₯0)) β‰Ό πœ”(π‘₯0, 𝑓(π‘₯0)) + πœ”(𝑓(π‘₯0), 𝑓 2(π‘₯0)) so that (3) become πœ”(𝑓(π‘₯0), 𝑓 2(π‘₯0)) β‰Ό π›Όπœ”(π‘₯0, 𝑓(π‘₯0)) + π›½πœ”(π‘₯0, 𝑓(π‘₯0)) + π›½πœ”(𝑓(π‘₯0), 𝑓 2(π‘₯0)) +π›Ύπœ”(π‘₯0, 𝑓 2(π‘₯0)) β‰Ό π›Όπœ”(π‘₯0, 𝑓(π‘₯0)) + π›½πœ”(π‘₯0, 𝑓(π‘₯0)) + π›½πœ”(𝑓(π‘₯0), 𝑓 2(π‘₯0)) +𝛾[πœ”(π‘₯0, 𝑓(π‘₯0)) + πœ”(𝑓(π‘₯0), 𝑓 2(π‘₯0))] = π›Όπœ”(π‘₯0, 𝑓(π‘₯0)) + π›½πœ”(π‘₯0, 𝑓(π‘₯0)) + π›½πœ”(𝑓(π‘₯0), 𝑓 2(π‘₯0)) +π›Ύπœ”(π‘₯0, 𝑓(π‘₯0)) + π›Ύπœ”(𝑓(π‘₯0), 𝑓 2(π‘₯0)) = π›Όπœ”(π‘₯0, 𝑓(π‘₯0)) + π›½πœ”(π‘₯0, 𝑓(π‘₯0)) + π›Ύπœ”(π‘₯0, 𝑓(π‘₯0)) +π›½πœ”(𝑓(π‘₯0), 𝑓 2(π‘₯0)) + π›Ύπœ”(𝑓(π‘₯0), 𝑓 2(π‘₯0)) = (𝛼 + 𝛽 + 𝛾)πœ”(π‘₯0, 𝑓(π‘₯0)) + (𝛽 + 𝛾)πœ”(𝑓(π‘₯0), 𝑓 2(π‘₯0)) or we can write πœ”(𝑓(π‘₯0), 𝑓 2(π‘₯0)) β‰Ό (𝛼 + 𝛽 + 𝛾)πœ”(π‘₯0, 𝑓(π‘₯0)) +(𝛽 + 𝛾)πœ”(𝑓(π‘₯0), 𝑓 2(π‘₯0)) πœ”(𝑓(π‘₯0), 𝑓 2(π‘₯0)) βˆ’ (𝛽 + 𝛾)πœ”(𝑓(π‘₯0), 𝑓 2(π‘₯0)) β‰Ό (𝛼 + 𝛽 + 𝛾)πœ”(π‘₯0, 𝑓(π‘₯0)) [1 βˆ’ (𝛽 + 𝛾)]πœ”(𝑓(π‘₯0), 𝑓 2(π‘₯0)) β‰Ό (𝛼 + 𝛽 + 𝛾)πœ”(π‘₯0, 𝑓(π‘₯0)) Ahmad Khairul Umam, Nihaya Alivia C. Dewi, and Pukky Tetralian B. N. Existence and Uniqueness of Fixed Points in Cone Metric Spaces for 𝝎-distance 109 πœ”(𝑓(π‘₯0), 𝑓 2(π‘₯0)) β‰Ό 𝛼 + 𝛽 + 𝛾 1 βˆ’ (𝛽 + 𝛾) πœ”(π‘₯0, 𝑓(π‘₯0)). Suppose 𝐾 = 𝛼+𝛽+𝛾 1βˆ’(𝛽+𝛾) according to definition 8 about contraction function, then πœ”(𝑓(π‘₯0), 𝑓 2(π‘₯0)) β‰Ό πΎπœ”(π‘₯0, 𝑓(π‘₯0)) (4) where 0 ≀ 𝐾 = 𝛼+𝛽+𝛾 1βˆ’(𝛽+𝛾) < 1. According (4), we get πœ”(𝑓 𝑛(π‘₯0), 𝑓 𝑛+1(π‘₯0)) β‰Ό πΎπœ”(𝑓 π‘›βˆ’1(π‘₯0), 𝑓 𝑛(π‘₯0)) β‰Ό β‹― β‰Ό 𝐾 𝑛 πœ”(π‘₯0, 𝑓(π‘₯0)) where 0 ≀ 𝐾 < 1. Let π‘š > 𝑛 β‰₯ 𝑁 ∈ β„•, according to triangle inequality then πœ”(𝑓 𝑛(π‘₯0), 𝑓 π‘š (π‘₯0)) β‰Ό πœ”(𝑓 𝑛(π‘₯0), 𝑓 𝑛+1(π‘₯0)) + πœ”(𝑓 𝑛+1(π‘₯0), 𝑓 𝑛+2(π‘₯0)) + β‹― +πœ”(𝑓 π‘šβˆ’2(π‘₯0), 𝑓 π‘šβˆ’1(π‘₯0)) + πœ”(𝑓 π‘šβˆ’1(π‘₯0), 𝑓 π‘š(π‘₯0)) β‰Ό 𝐾𝑛 πœ”(π‘₯0, 𝑓(π‘₯0)) + 𝐾 𝑛+1πœ”(π‘₯0, 𝑓(π‘₯0)) + β‹― +πΎπ‘šβˆ’2πœ”(π‘₯0, 𝑓(π‘₯0)) + 𝐾 π‘šβˆ’1πœ”(π‘₯0, 𝑓(π‘₯0)) = (𝐾𝑛 + 𝐾𝑛+1 + β‹― + πΎπ‘šβˆ’2 + πΎπ‘šβˆ’1)πœ”(π‘₯0, 𝑓(π‘₯0)) = 𝐾𝑛 (1 + 𝐾 + 𝐾2 + β‹― πΎπ‘šβˆ’π‘›βˆ’1)πœ”(π‘₯0, 𝑓(π‘₯0)) = 𝐾𝑛 ( βˆ‘ 𝐾𝑖 π‘šβˆ’π‘›βˆ’1 𝑖=0 ) πœ”(π‘₯0, 𝑓(π‘₯0)) β‰Ό 𝐾𝑛 (βˆ‘ 𝐾𝑖 ∞ 𝑖=0 ) πœ”(π‘₯0, 𝑓(π‘₯0)) = 𝐾𝑛 ( 1 1 βˆ’ 𝐾 ) πœ”(π‘₯0, 𝑓(π‘₯0)) = ( 𝐾𝑛 1 βˆ’ 𝐾 ) πœ”(π‘₯0, 𝑓(π‘₯0)). Suppose πœ”(π‘₯0, 𝑓(π‘₯0)) = 𝑐, then πœ”(𝑓 𝑛 (π‘₯0), 𝑓 π‘š(π‘₯0)) β‰Ό ( 𝐾𝑛 1 βˆ’ 𝐾 ) πœ”(π‘₯0, 𝑓(π‘₯0)) = 𝑐𝐾𝑛 1 βˆ’ 𝐾 . Choose 𝑁 ∈ β„• with 𝑁 < 𝐾 log (1 βˆ’ 𝐾) 𝑐 such that for all π‘š, 𝑛 β‰₯ 𝑁, we get πœ”(𝑓 𝑛(π‘₯0), 𝑓 π‘š(π‘₯0)) β‰Ό 𝑐𝐾𝑛 1 βˆ’ 𝐾 β‰Ό 𝑐𝐾𝑁 1 βˆ’ 𝐾 < 𝑐 1 βˆ’ 𝐾 . (1 βˆ’ 𝐾) 𝑐 = . So, sequence 〈π‘₯𝑛 βŒͺ is Cauchy sequence. Because space (𝑋, 𝑑) is complete cone metric space, then sequence 〈π‘₯𝑛 βŒͺ is convergent to point π‘₯ ∈ 𝑋 or we can write 〈π‘₯𝑛 βŒͺ β†’ π‘₯. And then, we will proof that point π‘₯ is fixed point of function 𝑓. According to triangle inequality and (2), then πœ”(𝑓(π‘₯), π‘₯) β‰Ό πœ”(𝑓(π‘₯), 𝑓(π‘₯𝑛 )) + πœ”(𝑓(π‘₯𝑛 ), π‘₯) β‰Ό π›Όπœ”(π‘₯, π‘₯𝑛 ) + 𝛽[πœ”(π‘₯, 𝑓(π‘₯)) + πœ”(π‘₯𝑛 , 𝑓(π‘₯𝑛 ))] +𝛾[πœ”(π‘₯, 𝑓(π‘₯𝑛 )) + πœ”(π‘₯𝑛 , 𝑓(π‘₯))] + πœ”(𝑓(π‘₯𝑛 ), π‘₯) = π›Όπœ”(π‘₯, π‘₯𝑛 ) + π›½πœ”(π‘₯, 𝑓(π‘₯)) + π›½πœ”(π‘₯𝑛 , 𝑓(π‘₯𝑛 )) +π›Ύπœ”(π‘₯, 𝑓(π‘₯𝑛 )) + π›Ύπœ”(π‘₯𝑛 , 𝑓(π‘₯)) + πœ”(𝑓(π‘₯𝑛 ), π‘₯) or we can write πœ”(𝑓(π‘₯), π‘₯) β‰Ό π›Όπœ”(π‘₯, π‘₯𝑛 ) + π›½πœ”(π‘₯, 𝑓(π‘₯)) + π›½πœ”(π‘₯𝑛 , 𝑓(π‘₯𝑛 )) +π›Ύπœ”(π‘₯, 𝑓(π‘₯𝑛 )) + π›Ύπœ”(π‘₯𝑛 , 𝑓(π‘₯)) + πœ”(𝑓(π‘₯𝑛 ), π‘₯) πœ”(𝑓(π‘₯), π‘₯) β‰Ό π›Όπœ”(π‘₯, π‘₯𝑛 ) + π›½πœ”(𝑓(π‘₯), π‘₯) + π›½πœ”(π‘₯𝑛 , 𝑓(π‘₯𝑛 )) +π›Ύπœ”(π‘₯, 𝑓(π‘₯𝑛 )) + π›Ύπœ”(π‘₯𝑛 , 𝑓(π‘₯)) + πœ”(𝑓(π‘₯𝑛 ), π‘₯) Jurnal Matematika MANTIK Vol. 8, No. 2, December 2022, pp. 105-112 110 πœ”(𝑓(π‘₯), π‘₯) βˆ’ π›½πœ”(𝑓(π‘₯), π‘₯) β‰Ό π›Όπœ”(π‘₯, π‘₯𝑛 ) + π›½πœ”(π‘₯𝑛 , 𝑓(π‘₯𝑛 )) + π›Ύπœ”(π‘₯, 𝑓(π‘₯𝑛 )) +π›Ύπœ”(π‘₯𝑛 , 𝑓(π‘₯)) + πœ”(𝑓(π‘₯𝑛 ), π‘₯) (1 βˆ’ 𝛽)πœ”(𝑓(π‘₯), π‘₯) β‰Ό π›Όπœ”(π‘₯, π‘₯𝑛 ) + π›½πœ”(π‘₯𝑛 , 𝑓(π‘₯𝑛 )) + π›Ύπœ”(π‘₯, 𝑓(π‘₯𝑛 )) +π›Ύπœ”(π‘₯𝑛 , 𝑓(π‘₯)) + πœ”(𝑓(π‘₯𝑛 ), π‘₯) (1 βˆ’ 𝛽)πœ”(𝑓(π‘₯), π‘₯) β‰Ό π›Όπœ”(π‘₯, π‘₯𝑛 ) + π›½πœ”(π‘₯𝑛 , 𝑓(π‘₯𝑛 )) + π›Ύπœ”(π‘₯𝑛 , 𝑓(π‘₯)) +π›Ύπœ”(π‘₯, 𝑓(π‘₯𝑛 )) + πœ”(𝑓(π‘₯𝑛 ), π‘₯) (1 βˆ’ 𝛽)πœ”(𝑓(π‘₯), π‘₯) β‰Ό π›Όπœ”(π‘₯, π‘₯𝑛 ) + π›½πœ”(π‘₯𝑛 , 𝑓(π‘₯𝑛 )) + π›Ύπœ”(π‘₯𝑛 , 𝑓(π‘₯)) +π›Ύπœ”(𝑓(π‘₯𝑛 ), π‘₯) + πœ”(𝑓(π‘₯𝑛 ), π‘₯) (1 βˆ’ 𝛽)πœ”(𝑓(π‘₯), π‘₯) β‰Ό π›Όπœ”(π‘₯, π‘₯𝑛 ) + π›½πœ”(π‘₯𝑛 , 𝑓(π‘₯𝑛 )) + π›Ύπœ”(π‘₯𝑛 , 𝑓(π‘₯)) +(𝛾 + 1)πœ”(𝑓(π‘₯𝑛 ), π‘₯) πœ”(𝑓(π‘₯), π‘₯) β‰Ό 𝛼 (1 βˆ’ 𝛽) πœ”(π‘₯, π‘₯𝑛 ) + 𝛽 (1 βˆ’ 𝛽) πœ”(π‘₯𝑛 , 𝑓(π‘₯𝑛 )) + 𝛾 (1 βˆ’ 𝛽) πœ”(π‘₯𝑛 , 𝑓(π‘₯)) + (𝛾 + 1) (1 βˆ’ 𝛽) πœ”(𝑓(π‘₯𝑛 ), π‘₯) πœ”(𝑓(π‘₯), π‘₯) β‰Ό 𝛼 (1 βˆ’ 𝛽) πœ”(π‘₯, π‘₯𝑛 ) + 𝛽 (1 βˆ’ 𝛽) πœ”(π‘₯𝑛 , π‘₯𝑛+1) + 𝛾 (1 βˆ’ 𝛽) πœ”(π‘₯𝑛 , 𝑓(π‘₯)) + (𝛾 + 1) (1 βˆ’ 𝛽) πœ”(π‘₯𝑛+1, π‘₯) because sequence 〈π‘₯𝑛 βŒͺ is convergent for 𝑛 β†’ ∞, then: πœ”(𝑓(π‘₯), π‘₯) β‰Ό 𝛼 (1 βˆ’ 𝛽) πœ”(π‘₯, π‘₯𝑛 ) + 𝛽 (1 βˆ’ 𝛽) πœ”(π‘₯𝑛 , π‘₯𝑛+1) + 𝛾 (1 βˆ’ 𝛽) πœ”(π‘₯𝑛 , 𝑓(π‘₯)) + (𝛾 + 1) (1 βˆ’ 𝛽) πœ”(π‘₯𝑛+1, π‘₯) = 𝛼 (1 βˆ’ 𝛽) (0) + 𝛽 (1 βˆ’ 𝛽) (0) + 𝛾 (1 βˆ’ 𝛽) (0) + (𝛾 + 1) (1 βˆ’ 𝛽) (0) = 0. (5) Because 0 β‰Ό πœ”(𝑓(π‘₯), π‘₯), according (5) then πœ”(𝑓(π‘₯), π‘₯) = 0, or we can write π‘₯ = 𝑓(π‘₯). So, point π‘₯ is fixed point of function 𝑓. Furthermore, we will proof uniqueness of a fixed point. Suppose π‘₯ and 𝑦 are fixed points of function 𝑓, such that π‘₯ = 𝑓(π‘₯) and 𝑦 = 𝑓(𝑦) then πœ”(π‘₯, 𝑦) = πœ”(𝑓(π‘₯), 𝑓(𝑦)) β‰Ό π›Όπœ”(π‘₯, 𝑦) + 𝛽[πœ”(π‘₯, 𝑓(π‘₯)) + πœ”(𝑦, 𝑓(𝑦))] + 𝛾[πœ”(π‘₯, 𝑓(𝑦)) + πœ”(𝑦, 𝑓(π‘₯))] = π›Όπœ”(π‘₯, 𝑦) + 𝛽[πœ”(π‘₯, π‘₯) + πœ”(𝑦, 𝑦)] + 𝛾[πœ”(π‘₯, 𝑦) + πœ”(𝑦, π‘₯)] = π›Όπœ”(π‘₯, 𝑦) + 𝛽[0 + 0] + 𝛾[πœ”(π‘₯, 𝑦) + πœ”(𝑦, π‘₯)] = π›Όπœ”(π‘₯, 𝑦) + 𝛽[0] + 𝛾[πœ”(π‘₯, 𝑦) + πœ”(𝑦, π‘₯)] = π›Όπœ”(π‘₯, 𝑦) + 0 + 𝛾[πœ”(π‘₯, 𝑦) + πœ”(𝑦, π‘₯)] = π›Όπœ”(π‘₯, 𝑦) + 𝛾[πœ”(π‘₯, 𝑦) + πœ”(𝑦, π‘₯)] = π›Όπœ”(π‘₯, 𝑦) + π›Ύπœ”(π‘₯, 𝑦) + π›Ύπœ”(𝑦, π‘₯) = π›Όπœ”(π‘₯, 𝑦) + π›Ύπœ”(π‘₯, 𝑦) + π›Ύπœ”(π‘₯, 𝑦) = π›Όπœ”(π‘₯, 𝑦) + 2π›Ύπœ”(π‘₯, 𝑦) = (𝛼 + 2𝛾)πœ”(π‘₯, 𝑦) because 𝛼 + 2𝛽 + 2𝛾 < 1 and 𝛼 + 2𝛾 < 1, so that πœ”(π‘₯, 𝑦) β‰Ό (𝛼 + 2𝛾)πœ”(π‘₯, 𝑦) is contradiction. So, point π‘₯ is unique fixed point of function 𝑓 in 𝑋. Ahmad Khairul Umam, Nihaya Alivia C. Dewi, and Pukky Tetralian B. N. Existence and Uniqueness of Fixed Points in Cone Metric Spaces for 𝝎-distance 111 Example 2. Let set 𝔼 = ℝ2, 𝑃 = {(π‘₯, 𝑦) ∈ 𝔼: π‘₯, 𝑦 β‰₯ 0} βŠ‚ ℝ2, 𝑋 = ℝ, and 𝑑: 𝑋 Γ— 𝑋 β†’ 𝔼 such that 𝑑(π‘₯, 𝑦) = (|π‘₯ βˆ’ 𝑦|, 𝛼|π‘₯ βˆ’ 𝑦|) where 𝛼 β‰₯ 0 is a constant, then (𝑋, 𝑑) is cone metric space. Example 3. Let metric space (𝑋, 𝑑) and function πœ”: 𝑋 Γ— 𝑋 β†’ [0, ∞). Function πœ”(π‘₯, 𝑦) = 𝑐 for every π‘₯, 𝑦 ∈ 𝑋 is πœ”-distance on 𝑋 (𝑐 is positive real number). Function πœ” is not metric space because πœ”(π‘₯, π‘₯) = 𝑐 β‰  0 for any π‘₯ ∈ 𝑋. 4. Conclusion Cone metric space is generalization of metric space. Range of cone metric in cone metric space is Banach space. In this research, we use πœ”-distance for metrik. a πœ”-distance is a function in metric spaces with three condition: symmetry, lower semicontinuous function, and relationship πœ”-distance with metric itself. Fixed point has many useful for solving linear equation, ordinary differential equation, partial differential equation, integral equation. The famous fixed-point theorem is Banach fixed point theorem. The Banach fixed point guarantee the existence and uniqueness of fixed point for function in complete space and contractive function. Let complete cone metric space with πœ”-distance. Let normal cone 𝑃 in 𝑋 and function 𝑓: 𝑋 β†’ 𝑋 that satisfy πœ”(𝑓(π‘₯), 𝑓(𝑦)) β‰Ό π›Όπœ”(π‘₯, 𝑦) + 𝛽[πœ”(π‘₯, 𝑓(π‘₯)) + πœ”(𝑦, 𝑓(𝑦))] + 𝛾[πœ”(π‘₯, 𝑓(𝑦)) + πœ”(𝑦, 𝑓(π‘₯))] for all π‘₯, 𝑦 ∈ 𝑋 where 𝛼, 𝛽, 𝛾 are non negative real numbers such that 𝛼 + 2𝛽 + 2𝛾 < 1, then 𝑓 has unique fixed point in 𝑋. References [1] S. Oltra, and O. Valero, " Banach’s Fixed Point Theorem for Partial Metric Spaces," Rend. Istit. Mat. Univ. Trieste, vol. 36, pp. 17-26, 2004. [2] H. L. Guang, and Z. Xian, "Cone Metric Spaces and Fixed Point Theorems of Contractive Mappings," J. Math. Anal. 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