PARADIGMA BARU PENDIDIKAN MATEMATIKA DAN APLIKASI ONLINE INTERNET PEMBELAJARAN How to cite: F. Y. Ishak, β€œExistence Solution for Nonlinear System of Fractional Integrodifferential Equations of Volterra Type with Fractional Boundary Conditions”, JMM, vol. 6, no. 1, pp. 1-12, May 2020. Existence Solution for Nonlinear System of Fractional Integrodifferential Equations of Volterra Type with Fractional Boundary Conditions Faraj Y. Ishak University of Duhok Iraq, faraj.ishak@uod.ac doi: https://doi.org/10.15642/mantik.2020.6.1.1-12 Abstrak: Artikel ini menyelidiki eksistensi, keunikan, dan solusi stabil dari sistem persamaan diferensial-diferensial Volterra fraksional baru dengan kondisi batas fraksional dengan menggunakan teorema eksistensi dan keunikan. Teorema tentang eksistensi dan keunikan dari solusi yang ditetapkan di bawah beberapa kondisi yang diperlukan dan cukup pada ruang kompak. Contoh sederhana dari hasil aplikasi utama disajikan dalam artikel ini. Kata kunci: Keberadaan dan keunikan, stabilitas, fractional Integrodifferential equations, masalah nilai batas, teorema eksistensi dan keunikan. Abstract: This article investigates existence, uniqueness and stability solutions of new fractional Volterra integro-differential equations system with fractional boundary conditions by using the existence and uniqueness theorem. Theorems on existence and uniqueness of solution are established under some necessary and sufficient conditions on compact space. A simple example of application of the main results of this article is presented. Keywords: Existence and uniqueness, stability, fractional Integrodifferential equations, boundary value problem, existence and uniqueness theorem. Jurnal Matematika MANTIK Vol. 6, No. 1, May 2020, pp. 1-12 ISSN: 2527-3159 (print) 2527-3167 (online) mailto:faraj.ishak@uod.ac http://u.lipi.go.id/1458103791 Jurnal Matematika MANTIK Volume 6, Issue. 1, May 2020, pp. 1-12 2 1. Introduction Gottfried Leibniz and Guilliaume L’Hopital sparked initial curiosity into the theory of fractional calculus during a 1695 correspondence on the possible value and meaning of non-integer-order derivatives. By the late nineteenth century, the combined efforts of a number of mathematicians most notably Liouville, Grunwald, Letnikov, and Riemann produced a fairly solid theory of fractional calculus for functions of a real variable. Though several viable fractional derivatives were proposed, the so-called Riemann- Liouville and Caputo derivatives are the two most-commonly used today. Mathematicians have employed this fractional calculus in recent years to model and solve a variety of applied problems. Indeed, as Podlubney outlines in [1]. Fractional differential equations have extensive applications in various fields of science and engineering. Many phenomena in viscoelasticity, electrochemistry, control theory, porous media, electromagnetism, and other fields, can be modelled by fractional differential equations. We refer the reader to [2, 4] and references therein for some applications. Fractional BVPs defined on intervals have been studied by many authors. Many results on the existence, uniqueness, multiplicity, and nonexistence of solutions for fractional differential equations subject to various boundary conditions (BCs) have been obtained; see for example [9,10,11,12,13,14,15,16]. The fractional difference calculus had its origin in the works by Al-Salam [6] and Agarwal [7]. More recently, perhaps due to the explosion in research within the fractional differential calculus setting, new developments in this theory of fractional difference calculus were made, specifically, analogues of the integral and differential fractional operators properties such as the Mittag-Leffler function, the Laplace transform, and Taylor’s formula [3,5,8,17,18], just to mention some. Butris and Ishak [20], used both methods Picard approximation and Banach fixed point theorems for studying the existence and uniqueness solutions to the following fractional integral equations: 𝑒(𝑑) = 𝑓(𝑑)+ 1 Ξ“(𝛼) ∫ (𝑑 βˆ’π‘ )π›Όβˆ’1𝐹(𝑑,𝑠,𝑒(𝑠),𝑀(𝑠))𝑑𝑠 𝑑 π‘Ž 𝑀(𝑑) = 𝑔(𝑑)+ 1 Ξ“(𝛼) ∫ (𝑑 βˆ’π‘ )π›Όβˆ’1𝐺(𝑑,𝑠,𝑒(𝑠),𝑀(𝑠))𝑑𝑠 𝑏 π‘Ž In this work our aim is to show the existence solutions of the system of integrodifferential equations 𝐷𝛼π‘₯(𝑑)+ 𝑓(𝑑,𝑠, [πœ™ π‘₯](π‘₯)) = 0 𝐷𝛽𝑦(𝑑) +𝑔(𝑑,𝑠, [πœ‘ 𝑦](𝑦)) = 0 π·π›Όβˆ’1π‘₯(0) = 0, π·π›Όβˆ’1π‘₯(1) = 𝑏1, π·π›½βˆ’1𝑦(0) = 0, π·π›½βˆ’1𝑦(1) = 𝑏2 Where: [πœ™ π‘₯](π‘₯) = ∫ 𝐾(𝑑,𝑠)𝐹(𝑑,𝑠,π‘₯(𝑠),𝑦(𝑠))𝑑𝑠 𝑑 βˆ’βˆž , [πœ‘ 𝑦](𝑦) = ∫ 𝐺(𝑑,𝑠)𝐻(𝑑,𝑠,π‘₯(𝑠),𝑦(𝑠))𝑑𝑠 𝑑 βˆ’βˆž 1 < 𝛼,𝛽 ≀ 2,0 ≀ 𝑠 ≀ 𝑑 ≀ 1,𝑏1,𝑏2 ∈ 𝑅, π‘₯ ∈ 𝐷1 βŠ† 𝑅 𝑛 and 𝑦 ∈ 𝐷2 βŠ† 𝑅 π‘š,𝐷1 and 𝐷2 are compact domain, let the vector functions 𝐹(𝑑,𝑠,π‘₯(𝑑),𝑦(𝑑)) , 𝐻(𝑑,𝑠,π‘₯(𝑑),𝑦(𝑑)) is defined and continuous on the domain: 𝐷 = {(𝑑,𝑠,π‘₯,𝑦);𝑑,𝑠 πœ– [0,1] ,π‘₯ ∈ 𝐷1 ,𝑦 ∈ 𝐷2} (1.2) (1.1) F. Y. Ishak Existence Solution for Nonlinear System of Fractional Integrodifferential Equations of Volterra Type with Fractional Boundary Conditions 3 Assume that the vector functions 𝐹(𝑑,𝑠,π‘₯(𝑑),𝑦(𝑑)), 𝐻(𝑑,𝑠,π‘₯(𝑑),𝑦(𝑑)), and kernels 𝐾(𝑑,𝑠),𝐺(𝑑,𝑠) are satisfying the following inequalities: ‖𝐹(𝑑,𝑠,π‘₯(𝑑),𝑦(𝑑))β€– ≀ 𝑀1 , ‖𝐻(𝑑,𝑠,π‘₯(𝑑),𝑦(𝑑))β€– ≀ 𝑀2 (1.3) ‖𝐹(𝑑,𝑠,π‘₯2,𝑦2)βˆ’ 𝐹(𝑑,𝑠,π‘₯1,𝑦1)β€– ≀ 𝐿1(β€–π‘₯2 βˆ’π‘₯1β€–+ ‖𝑦2 βˆ’π‘¦1β€–) (1.4) ‖𝐻(𝑑,𝑠,π‘₯2,𝑦2)βˆ’ 𝐻(𝑑,𝑠,π‘₯1,𝑦1)β€– ≀ 𝐿2(β€–π‘₯2 βˆ’ π‘₯1β€–+ ‖𝑦2 βˆ’π‘¦1β€–) (1.5) ‖𝐾(𝑑,𝑠)β€– ≀ 𝛿1𝑒 βˆ’πœ†1(π‘‘βˆ’π‘ ) , ‖𝐺(𝑑,𝑠)β€– ≀ 𝛿2𝑒 βˆ’πœ†2(π‘‘βˆ’π‘ ) (1.6) Where 𝑀1,𝑀2,𝐿1,𝐿2,πœ†1,πœ†2,𝛿1,𝛿2,are positive constants π‘₯1,π‘₯2 ∈ 𝐷 1 𝑦1,𝑦2 ∈ 𝐷2 𝑑 ,𝑠 πœ– [0,1] and β€–.β€– = max π‘‘βˆˆ[0,1] |. |, we defined non-empty sets as: 𝐷𝐹 = 𝐷1 βˆ’ 𝑀1𝛿1(π›Όβˆ’1)+𝑏1πœ†1𝛼 πœ†1𝛀(𝛼+1) 𝐷𝐻 = 𝐷2 βˆ’ 𝑀2𝛿2(π›½βˆ’1)+πœ†2𝑏2Ξ² πœ†2Ξ“(𝛽+1) As well as we suppose the maximum value of the following matrix: Ξ”0 = ( 𝐿1𝛿1(π›Όβˆ’1) πœ†1Ξ“(𝛼+1) 𝐿1𝛿1(π›Όβˆ’1) πœ†1Ξ“(𝛼+1) 𝐿2𝛿2(π›½βˆ’1) πœ†2Ξ“(𝛽+1) 𝐿2𝛿2(π›½βˆ’1) πœ†2Ξ“(𝛽+1) ) , less than one i.e. . πœ† π‘šπ‘Žπ‘₯(Ξ”0) = 𝐿1𝛿1(π›Όβˆ’1) πœ†1Ξ“(𝛼+1) + 𝐿2𝛿2(π›½βˆ’1) πœ†2Ξ“(𝛽+1) < 1 (1.8) Define a sequence of functions {π‘₯π‘š(𝑑,π‘₯0)}π‘š=0 ∞ , {π‘¦π‘š(𝑑,𝑦0)}π‘š=0 ∞ as: π‘₯π‘š+1(𝑑,π‘₯0) = π‘‘π›Όβˆ’1 Ξ“(𝛼) ∫ 1 0 ∫ 𝐾(𝑑,𝑠)𝐹(𝑑,𝑠,π‘₯π‘š(𝑠),π‘¦π‘š(𝑠))𝑑𝑠𝑑𝑠 𝑑 βˆ’βˆž βˆ’ ∫ (π‘‘βˆ’π‘ )π›Όβˆ’1 Ξ“(𝛼) 𝑑 0 (∫ 𝐾(𝑑,𝑠)𝐹(𝑑,𝑠,π‘₯π‘š(𝑠),π‘¦π‘š(𝑠))𝑑𝑠)𝑑𝑠 𝑑 βˆ’βˆž + 𝑏1𝑑 π›Όβˆ’1 Ξ“(Ξ±) π‘¦π‘š+1(𝑑,𝑦0) = π‘‘π›½βˆ’1 Ξ“(𝛽) ∫ 1 0 ∫ 𝐺(𝑑,𝑠)𝐻(𝑑,𝑠,π‘₯π‘š(𝑠),π‘¦π‘š(𝑠))𝑑𝑠𝑑𝑠 𝑑 βˆ’βˆž βˆ’ ∫ (π‘‘βˆ’π‘ )π›½βˆ’1 Ξ“(𝛽) 𝑑 0 (∫ 𝐺(𝑑,𝑠)𝐻(𝑑,𝑠,π‘₯π‘š(𝑠),π‘¦π‘š(𝑠))𝑑𝑠)𝑑𝑠 𝑑 βˆ’βˆž + 𝑏2𝑑 π›½βˆ’1 Ξ“(Ξ²) With π‘₯0 = π‘₯(0) = 0, 𝑦0 = 𝑦(0) = 0, m = 0,1,2… 2. Preliminaries Let us recall some basic definitions on fractional calculus, which can be found in the literature. Definition 2.1 [19] Assume that 𝑓(π‘₯,𝑦) is defined on the set (π‘Ž,𝑏)x𝐺,𝐺 βŠ‚ 𝑅,𝑓(π‘₯,𝑦) is said to satisfy Lipschitz condition with respect to the second variable, if for all π‘₯ ∈ (π‘Ž,𝑏) and for any 𝑦1 ,𝑦2 ∈ 𝐺 |𝑓(π‘₯,𝑦1)βˆ’π‘“(π‘₯,𝑦2)| ≀ πœ‰|𝑦1 βˆ’ 𝑦2| (1.9) (1.7) Jurnal Matematika MANTIK Volume 6, Issue. 1, May 2020, pp. 1-12 4 where πœ‰ > 0 does not depend on π‘₯ ∈ (π‘Ž,𝑏). Definition 2.2 [19] The Riemann-Liouville fractional integral of order q is defined by πΌπ‘žπ‘“(𝑑) = 1 Ξ“(π‘ž) ∫ (𝑑 βˆ’ 𝑠)π‘žβˆ’1 𝑑 0 𝑓(𝑠)𝑑𝑠, π‘ž > 0 provided the integral exists. Definition 2.3 [19] The Riemann-Liouville fractional derivative of order q is defined by π·π‘žπ‘“(𝑑) = 1 Ξ“(π‘›βˆ’ π‘ž) ( 𝑑 𝑑𝑑 ) 𝑛 ∫ (𝑑 βˆ’ 𝑠)π‘›βˆ’π‘žβˆ’1 𝑑 0 𝑓(𝑠)𝑑𝑠, 𝑛 βˆ’1 < π‘ž ≀ 𝑛, π‘ž > 0, Provided the right-hand side is pointwise defined on (0,+∞). Lemma 2.1 For 𝛼,𝛽 > 0, then the following relation hold: 𝐷𝛼𝑑𝛽 = Ξ“(𝛽 + 1) Ξ“(𝛽 +1 βˆ’π›Ό) π‘‘π›½βˆ’π›Όβˆ’1,𝛽 > 𝑛 π‘Žπ‘›π‘‘ π·π›Όπ‘‘π‘˜ = 0,π‘˜ = 0,1,…,𝑛 βˆ’1 Lemma 2.2 [3] The equality 𝐷0+ 𝛼 𝐼0+ 𝛼 𝑓(𝑑) = 𝑓(𝑑), 𝛼 > 0 holds for 𝑓 ∈ 𝐿1(0,1). Lemma 2.3 Let 𝛼,𝛽 > 0 and let f be a function defined on [0, 1]. Then the following formulas hold: (i) (πΌπ‘ž 𝛽 πΌπ‘ž 𝛼𝑓)(π‘₯) = (πΌπ‘ž 𝛼+𝛽 𝑓)(π‘₯) (ii) (π·π‘ž π›ΌπΌπ‘ž 𝛼𝑓)(π‘₯) = 𝑓(π‘₯) Lemma 2.4 Let 𝛼 > 0 and n be a positive integer. Then, the following equality holds: (πΌπ‘ž 𝛽 π·π‘ž 𝛼𝑓)(π‘₯) = (π·π‘ž π‘›πΌπ‘ž 𝛼𝑓)(π‘₯) βˆ’βˆ‘ π‘₯π›Όβˆ’π‘›+π‘˜ Ξ“(Ξ±+kβˆ’n+1) (π·π‘ž π‘˜π‘“)(0)π‘›βˆ’1π‘˜=0 Lemma 2.5 A functions π‘₯(𝑑),𝑦(𝑑), are solution of system (1.1) if and only if π‘₯(𝑑),𝑦(𝑑) have the form: π‘₯ (𝑑) = π‘‘π›Όβˆ’1 Ξ“(𝛼) ∫ 1 0 ∫ 𝐾(𝑑,𝑠)𝐹(𝑑,𝑠,π‘₯ (𝑠),𝑦 (𝑠))𝑑𝑠𝑑𝑠 𝑑 βˆ’βˆž βˆ’βˆ« (𝑑 βˆ’π‘ )π›Όβˆ’1 Ξ“(𝛼) 𝑑 0 (∫ 𝐾(𝑑,𝑠)𝐹(𝑑,𝑠,π‘₯ (𝑠),𝑦 (𝑠))𝑑𝑠)𝑑𝑠 𝑑 βˆ’βˆž + 𝑏1𝑑 π›Όβˆ’1 Ξ“(Ξ±) 𝑦 (𝑑) = π‘‘π›½βˆ’1 𝛀(𝛽) ∫ 1 0 ∫ 𝐺(𝑑,𝑠)𝐻(𝑑,𝑠,π‘₯ (𝑠),𝑦 (𝑠))𝑑𝑠𝑑𝑠 𝑑 βˆ’βˆž βˆ’βˆ« (𝑑 βˆ’π‘ )π›½βˆ’1 𝛀(𝛽) 𝑑 0 (∫ 𝐺(𝑑,𝑠)𝐻(𝑑,𝑠,π‘₯ (𝑠),π‘¦π‘š(𝑠))𝑑𝑠)𝑑𝑠 𝑑 βˆ’βˆž + 𝑏2𝑑 π›½βˆ’1 𝛀(𝛽) Proof: It follows from Lemma 2.4 that the system of fractional differential equation in (1.1) is equivalent to the integral equations: π‘₯(𝑑) = βˆ’πΌπ›Όπ‘“(𝑑)+ 𝑐1𝑑 π›Όβˆ’1 + 𝑐2𝑑 π›Όβˆ’2 𝑦(𝑑) = βˆ’πΌπ›Όπ‘”(𝑑)+𝑑1𝑑 π›Όβˆ’1 +𝑑2𝑑 π›Όβˆ’2 (2.1) F. Y. Ishak Existence Solution for Nonlinear System of Fractional Integrodifferential Equations of Volterra Type with Fractional Boundary Conditions 5 Where: 𝑓(𝑑) = ∫ 𝐾(𝑑,𝑠)𝐹(𝑑,𝑠,π‘₯ (𝑠),𝑦 (𝑠)) 𝑑𝑠 𝑑 βˆ’βˆž , 𝑔(𝑑) = ∫ 𝐺(𝑑,𝑠)𝐻(𝑑,𝑠,π‘₯ (𝑠),𝑦 (𝑠))𝑑𝑠 𝑑 βˆ’βˆž , 𝑐1,𝑐2,𝑑1,𝑑2 ∈ 𝑅 From the boundary conditions of (1.1) we have 𝑐2 = 0,𝑑2 = 0 and: 𝑐1 = 𝑏1 Ξ“(𝛼) + 1 Ξ“(𝛼) ∫ 𝑓(𝑠)𝑑𝑠 1 0 , 𝑑1 = 𝑏2 Ξ“(𝛽) + 1 Ξ“(𝛽) ∫ 𝑔(𝑠)𝑑𝑠 1 0 Which is complete the proof. 3. Result and Discussion In this section, the theorems of existence, uniqueness, and stability of a solution for system (1.1) will be given. Theorem 3.1: Let the right side of system (1.1) are defined and continuous on domain (1.2) .Suppose that the vector functions 𝐹(𝑑,𝑠,π‘₯(𝑑),𝑦(𝑑)) , 𝐻(𝑑,𝑠,π‘₯(𝑑),𝑦(𝑑)) are satisfying the inequalities (1.3)-(1.5) and the conditions (1.6)-(1.9).Then there exist a sequences of functions (1.9) converges uniformly as π‘š β†’ ∞ on domain (1.2) to the limit functions which satisfying integral equations (2.1) Provided that: β€–π‘₯∞(𝑑,π‘₯0)βˆ’ π‘₯0β€– ≀ 𝑀1𝛿1(π›Όβˆ’1)+πœ†1𝑏1𝛼 πœ†1Ξ“(𝛼+1) β€–π‘¦βˆž(𝑑,π‘₯0)βˆ’ 𝑦0β€– ≀ 𝑀2𝛿2(π›½βˆ’1)+πœ†2𝑏2Ξ² πœ†2Ξ“(𝛽+1) ( β€–π‘₯π‘š+1(𝑑,π‘₯0) βˆ’π‘₯π‘š(𝑑,π‘₯0)β€– ‖𝑦m+1(𝑑,𝑦0)βˆ’π‘¦m(𝑑,𝑦0)β€– ) ≀ Ξ”0 π‘š(𝐼 βˆ’ Ξ”0) βˆ’1Ξ¦0 for all π‘š β‰₯ 1 , 𝑑 ∈ [0,1] Proof: By using the sequence of function (1.9) when m=0, we get: β€–π‘₯1(𝑑,π‘₯0)βˆ’π‘₯0β€– ≀ π‘‘π›Όβˆ’1 Ξ“(𝛼) ∫ 1 0 ∫ ‖𝐾(𝑑,𝑠)‖‖𝐹(𝑑,𝑠,π‘₯0 (𝑠),𝑦0 (𝑠))β€– 𝑑𝑠𝑑𝑠 𝑑 βˆ’βˆž βˆ’ ∫ (π‘‘βˆ’π‘ )π›Όβˆ’1 Ξ“(𝛼) 𝑑 0 (∫ ‖𝐾(𝑑,𝑠)‖‖𝐹(𝑑,𝑠,π‘₯0 (𝑠),𝑦0 (𝑠))‖𝑑𝑠)𝑑𝑠 𝑑 βˆ’βˆž + 𝑏1𝑑 π›Όβˆ’1 Ξ“(Ξ±) ≀ π‘‘π›Όβˆ’1𝑀1 Ξ“(𝛼) ∫ 1 0 βˆ«π›Ώ1𝑒 βˆ’πœ†1(π‘‘βˆ’π‘ ) 𝑑𝑠𝑑𝑠 𝑑 βˆ’βˆž βˆ’βˆ« (𝑑 βˆ’π‘ )π›Όβˆ’1 Ξ“(𝛼) 𝑑 0 (∫ 𝛿1𝑒 βˆ’πœ†1(π‘‘βˆ’π‘ )𝑑𝑠)𝑑𝑠 𝑑 βˆ’βˆž + 𝑏1𝑑 π›Όβˆ’1 Ξ“(Ξ±) ≀ 𝑀1𝛿1 πœ†1Ξ“(𝛼) βˆ’ 𝑀1𝛿1 πœ†1Ξ“(𝛼 +1) + 𝑏1 Ξ“(Ξ±) ≀ 𝑀1𝛿1(π›Όβˆ’ 1)+ 𝑏1πœ†1𝛼 πœ†1𝛀(𝛼 + 1) And by the same we have ‖𝑦1(𝑑,𝑦0)βˆ’ 𝑦0β€– ≀ 𝑀2𝛿2(π›½βˆ’ 1)+ πœ†2𝑏2Ξ² πœ†2Ξ“(𝛽 +1) That is: π‘₯1(𝑑,π‘₯0)πœ–π·1 𝑦1(𝑑,𝑦0)πœ–π·2, for all π‘‘πœ–[0,1],π‘₯0 πœ– 𝐷𝐹,𝑦0 ∈ 𝐷𝐻 (3.1) Jurnal Matematika MANTIK Volume 6, Issue. 1, May 2020, pp. 1-12 6 Suppose that π‘₯𝑝(𝑑,π‘₯0) πœ– 𝐷1 ,𝑦𝑝(𝑑,𝑦0) πœ– 𝐷2 for each π‘₯0 πœ– 𝐷𝐹 ,𝑦0 πœ– 𝐷𝐻 ,π‘πœ–π‘ + , t∈ [0,1] ,by mathematical induction we conclude that: π‘₯π‘š(𝑑,π‘₯0) πœ– 𝐷1 ,π‘¦π‘š(𝑑,𝑦0) πœ– 𝐷2 for each π‘₯0 πœ– 𝐷𝐹 ,𝑦0 πœ– 𝐷𝐻 , π‘š = 0,1,2,… To prove that the sequences (1.9) convergence uniformly in domain (1.2): β€–π‘₯2(𝑑,π‘₯0)βˆ’π‘₯1(𝑑,π‘₯0)β€– ≀ π‘‘π›Όβˆ’1 Ξ“(𝛼) ∫ 1 0 ∫ ‖𝐾(𝑑,𝑠)‖‖𝐹(𝑑,𝑠,π‘₯1 (𝑠),𝑦1 (𝑠))β€– 𝑑𝑠𝑑𝑠 𝑑 βˆ’βˆž βˆ’ ∫ (π‘‘βˆ’π‘ )π›Όβˆ’1 Ξ“(𝛼) 𝑑 0 (∫ ‖𝐾(𝑑,𝑠)‖‖𝐹(𝑑,𝑠,π‘₯1 (𝑠),𝑦1 (𝑠))‖𝑑𝑠)𝑑𝑠 𝑑 βˆ’βˆž βˆ’ π‘‘π›Όβˆ’1 Ξ“(𝛼) ∫ 1 0 ∫ ‖𝐾(𝑑,𝑠)‖‖𝐹(𝑑,𝑠,π‘₯0 (𝑠),𝑦0 (𝑠))β€– 𝑑𝑠𝑑𝑠 𝑑 βˆ’βˆž + ∫ (π‘‘βˆ’π‘ )π›Όβˆ’1 Ξ“(𝛼) 𝑑 0 (∫ ‖𝐾(𝑑,𝑠)‖‖𝐹(𝑑,𝑠,π‘₯0 (𝑠),𝑦0 (𝑠))‖𝑑𝑠)𝑑𝑠 𝑑 βˆ’βˆž ≀ π‘‘π›Όβˆ’1 Ξ“(𝛼) ∫ 1 0 ∫ 𝛿1𝑒 βˆ’πœ†1(π‘‘βˆ’π‘ ) ‖𝐹(𝑑,𝑠,π‘₯1 (𝑠),𝑦1 (𝑠))βˆ’ 𝐹(𝑑,𝑠,π‘₯0 (𝑠),𝑦0 (𝑠))β€– 𝑑𝑠𝑑𝑠 𝑑 βˆ’βˆž βˆ’βˆ« (π‘‘βˆ’π‘ )π›Όβˆ’1 Ξ“(𝛼) 𝑑 0 (∫ 𝛿1𝑒 βˆ’πœ†1(π‘‘βˆ’π‘ ) ‖𝐹(𝑑,𝑠,π‘₯1 (𝑠),𝑦1 (𝑠))βˆ’ 𝐹(𝑑,𝑠,π‘₯0 (𝑠),𝑦0 (𝑠))‖𝑑𝑠)𝑑𝑠 𝑑 βˆ’βˆž ≀ 𝐿1𝑑 π›Όβˆ’1 Ξ“(𝛼) (β€–π‘₯1 βˆ’π‘₯0β€– +‖𝑦1 βˆ’π‘¦0β€–)∫ 1 0 ∫ 𝛿1𝑒 βˆ’πœ†1(π‘‘βˆ’π‘ ) 𝑑𝑠𝑑𝑠 𝑑 βˆ’βˆž βˆ’ 𝐿1(β€–π‘₯1 βˆ’ π‘₯0β€–+ ‖𝑦1 βˆ’ 𝑦0β€–)∫ (π‘‘βˆ’π‘ )π›Όβˆ’1 Ξ“(𝛼) 𝑑 0 (∫ 𝛿1𝑒 βˆ’πœ†1(π‘‘βˆ’π‘ ) 𝑑 βˆ’βˆž 𝑑𝑠)𝑑𝑠 ≀ 𝐿1𝛿1(𝛼𝑑 π›Όβˆ’1 βˆ’π‘‘π›Ό) πœ†1Ξ“(𝛼 +1) (β€–π‘₯1 βˆ’ π‘₯0β€–+ ‖𝑦1 βˆ’π‘¦0β€–) And by the same ‖𝑦2(𝑑,𝑦0)βˆ’π‘¦1(𝑑,𝑦0)β€– ≀ 𝐿2𝛿2(𝛽𝑑 π›½βˆ’1 βˆ’ 𝑑𝛽) πœ†2𝛀(𝛽 +1) βˆ’(β€–π‘₯1 βˆ’π‘₯0β€– +‖𝑦1 βˆ’ 𝑦0β€–) By the mathematical induction the following inequalities hold: β€–π‘₯π‘š+1(𝑑,π‘₯0)βˆ’π‘₯π‘š(𝑑,π‘₯0)β€– ≀ 𝐿1𝛿1(𝛼𝑑 π›Όβˆ’1βˆ’π‘‘π›Ό) πœ†1Ξ“(𝛼+1) (β€–π‘₯π‘š βˆ’ π‘₯π‘šβˆ’1β€–+ β€–π‘¦π‘š βˆ’ π‘¦π‘šβˆ’1β€–) β€–π‘¦π‘š+1(𝑑,𝑦0)βˆ’π‘¦π‘š(𝑑,𝑦0)β€– ≀ 𝐿2𝛿2(𝛽𝑑 π›½βˆ’1βˆ’π‘‘π›½) πœ†2Ξ“(𝛽+1) (β€–π‘₯π‘š βˆ’ π‘₯π‘šβˆ’1β€–+ β€–π‘¦π‘š βˆ’π‘¦π‘šβˆ’1β€–) Rewrite (3.2) with vector form: ( β€–π‘₯π‘š+1(𝑑,π‘₯0)βˆ’ π‘₯π‘š(𝑑,π‘₯0)β€– ‖𝑦m+1(𝑑,𝑦0)βˆ’ 𝑦m(𝑑,𝑦0)β€– ) ≀ ( 𝐿1𝛿1(𝛼𝑑 π›Όβˆ’1 βˆ’ 𝑑𝛼) πœ†1Ξ“(𝛼 +1) 𝐿1𝛿1(𝛼𝑑 π›Όβˆ’1 βˆ’π‘‘π›Ό) πœ†1Ξ“(𝛼 +1) 𝐿2𝛿2(𝛽𝑑 π›½βˆ’1 βˆ’ 𝑑𝛽) πœ†2Ξ“(𝛽+1) 𝐿2𝛿2(𝛽𝑑 π›½βˆ’1 βˆ’π‘‘π›½) πœ†2Ξ“(𝛽+ 1) ) ( β€–π‘₯π‘š βˆ’ π‘₯π‘šβˆ’1β€– β€–π‘¦π‘š βˆ’ π‘¦π‘šβˆ’1β€– ) That is: Ξ¦π‘š+1(𝑑,π‘₯0,𝑦0) ≀ Ξ”(𝑑)Ξ¦π‘š(𝑑,π‘₯0,𝑦0) (3.3) Where: (3.2) F. Y. Ishak Existence Solution for Nonlinear System of Fractional Integrodifferential Equations of Volterra Type with Fractional Boundary Conditions 7 Ξ”(𝑑) = ( 𝐿1𝛿1(𝛼𝑑 π›Όβˆ’1βˆ’π‘‘π›Ό) πœ†1Ξ“(𝛼+1) 𝐿1𝛿1(𝛼𝑑 π›Όβˆ’1βˆ’π‘‘π›Ό) πœ†1Ξ“(𝛼+1) 𝐿2𝛿2(𝛽𝑑 π›½βˆ’1βˆ’π‘‘π›½) πœ†2Ξ“(𝛽+1) 𝐿2𝛿2(𝛽𝑑 π›½βˆ’1βˆ’π‘‘π›½) πœ†2Ξ“(𝛽+1) ),Ξ¦π‘š+1 = ( β€–π‘₯π‘š+1(𝑑,π‘₯0) βˆ’π‘₯π‘š(𝑑,π‘₯0)β€– ‖𝑦m+1(𝑑,𝑦0)βˆ’π‘¦m(𝑑,𝑦0)β€– ) ,Ξ¦π‘š = ( β€–π‘₯π‘š βˆ’π‘₯π‘šβˆ’1β€– β€–π‘¦π‘š βˆ’ π‘¦π‘šβˆ’1β€– ) Take the maximum value for both sides of (3.3): Ξ¦ π‘š+1 ≀ Ξ”0 Ξ¦π‘š (3.4) where Ξ”0 = max π‘‘πœ–[0,1] Ξ” (𝑑), Ξ”0 = ( 𝐿1𝛿1(π›Όβˆ’1) πœ†1Ξ“(𝛼+1) 𝐿1𝛿1(π›Όβˆ’1) πœ†1Ξ“(𝛼+1) 𝐿2𝛿2(π›½βˆ’1) πœ†2Ξ“(𝛽+1) 𝐿2𝛿2(π›½βˆ’1) πœ†2Ξ“(𝛽+1) ) By repletion of (3.4) we obtain: Ξ¦π‘š+1 ≀ Ξ›0 π‘š Ξ¦1 Ξ¦1 ≀ ( 𝑀1𝛿1(π›Όβˆ’1)+πœ†1𝑏1𝛼 πœ†1Ξ“(𝛼+1) 𝑀2𝛿2(π›½βˆ’1)+πœ†2𝑏2Ξ² πœ†2Ξ“(𝛽+1) ),and also we get: βˆ‘ Φ𝑖 π‘š 𝑖=1 ≀ βˆ‘ Ξ”0 π‘–βˆ’1Ξ¦1 π‘š 𝑖=1 (3.5) Since the matrix Ξ”0 has eigenvalue πœ†1 = 0, πœ†2 = πœ†π‘šπ‘Žπ‘₯(Ξ”0) = 𝑀1𝛿1(𝛼 βˆ’1) +πœ†1𝑏1𝛼 πœ†1Ξ“(𝛼+ 1) + 𝑀2𝛿2(𝛽 βˆ’ 1)+ πœ†2𝑏2Ξ² πœ†2Ξ“(𝛽 +1) < 1 the series (3.5) is uniformly convergent, i.e. lim π‘šβ†’βˆž βˆ‘ Ξ”0 π‘–βˆ’1Ξ¦1 π‘š 𝑖=1 = βˆ‘ Ξ”0 π‘–βˆ’1Ξ¦1 ∞ 𝑖=1 = (𝐼 βˆ’Ξ”0) βˆ’1Ξ¦1 (3.6) Thus the limiting relation (3.6) signifies uniform convergence of sequences: {π‘₯π‘š(𝑑,π‘₯0)}π‘š=0 ∞ , {π‘¦π‘š(𝑑,𝑦0)}π‘š=0 ∞ ,that is: lim π‘šβ†’βˆž π‘₯π‘š(𝑑,π‘₯0) = π‘₯ (𝑑,π‘₯0) ,and lim π‘šβ†’βˆž π‘¦π‘š(𝑑,𝑦0) = 𝑦 (𝑑,𝑦0) By all conditions and inequalities of the theorem the estimate ( β€–π‘₯π‘š+1(𝑑,π‘₯0) βˆ’π‘₯π‘š(𝑑,π‘₯0)β€– ‖𝑦m+1(𝑑,𝑦0)βˆ’π‘¦m(𝑑,𝑦0)β€– ) ≀ Ξ”0 π‘š(𝐼 βˆ’ Ξ”0) βˆ’1Ξ¦1 Is hold for all m=1, 2, … To prove that π‘₯ (𝑑,π‘₯0)πœ–π·1 and 𝑦(𝑑,𝑦0)πœ–π·2 we prove that: lim π‘šβ†’βˆž ( π‘‘π›Όβˆ’1 Ξ“(𝛼) ∫ 1 0 ∫ 𝐾(𝑑,𝑠)𝐹(𝑑,𝑠,π‘₯π‘š(𝑠),π‘¦π‘š(𝑠))𝑑𝑠𝑑𝑠 𝑑 βˆ’βˆž βˆ’βˆ« (𝑑 βˆ’π‘ )π›Όβˆ’1 Ξ“(𝛼) 𝑑 0 (∫ 𝐾(𝑑,𝑠)𝐹(𝑑,𝑠,π‘₯π‘š(𝑠),π‘¦π‘š(𝑠))𝑑𝑠)𝑑𝑠 𝑑 βˆ’βˆž + 𝑏1𝑑 π›Όβˆ’1 Ξ“(Ξ±) ) = Jurnal Matematika MANTIK Volume 6, Issue. 1, May 2020, pp. 1-12 8 π‘‘π›Όβˆ’1 Ξ“(𝛼) ∫ 1 0 ∫ 𝐾(𝑑,𝑠)𝐹(𝑑,𝑠,π‘₯ (𝑠),𝑦 (𝑠))𝑑𝑠𝑑𝑠 𝑑 βˆ’βˆž βˆ’ ∫ (π‘‘βˆ’π‘ )π›Όβˆ’1 Ξ“(𝛼) 𝑑 0 (∫ 𝐾(𝑑,𝑠)𝐹(𝑑,𝑠,π‘₯ (𝑠),𝑦 (𝑠))𝑑𝑠)𝑑𝑠 𝑑 βˆ’βˆž + 𝑏1𝑑 π›Όβˆ’1 Ξ“(Ξ±) (3.7) lim π‘šβ†’βˆž ( π‘‘π›½βˆ’1 Ξ“(𝛽) ∫ 1 0 ∫ 𝐺(𝑑,𝑠)𝐻(𝑑,𝑠,π‘₯π‘š(𝑠),π‘¦π‘š(𝑠))𝑑𝑠𝑑𝑠 𝑑 βˆ’βˆž βˆ’βˆ« (𝑑 βˆ’π‘ )π›½βˆ’1 Ξ“(𝛽) 𝑑 0 (∫ 𝐺(𝑑,𝑠)𝐻(𝑑,𝑠,π‘₯π‘š(𝑠),π‘¦π‘š(𝑠))𝑑𝑠)𝑑𝑠 𝑑 βˆ’βˆž + 𝑏2𝑑 π›½βˆ’1 Ξ“(Ξ²) = π‘‘π›½βˆ’1 Ξ“(𝛽) ∫ 1 0 ∫ 𝐺(𝑑,𝑠)𝐻(𝑑,𝑠,π‘₯ (𝑠),𝑦 (𝑠))𝑑𝑠𝑑𝑠 𝑑 βˆ’βˆž βˆ’ ∫ (π‘‘βˆ’π‘ )π›½βˆ’1 Ξ“(𝛽) 𝑑 0 (∫ 𝐺(𝑑,𝑠)𝐻(𝑑,𝑠,π‘₯ (𝑠),𝑦 (𝑠))𝑑𝑠)𝑑𝑠 𝑑 βˆ’βˆž + 𝑏2𝑑 π›½βˆ’1 Ξ“(Ξ²) (3.8) We have: β€– π‘‘π›Όβˆ’1 Ξ“(𝛼) ∫ 1 0 ∫ 𝐾(𝑑,𝑠)𝐹(𝑑,𝑠,π‘₯π‘š(𝑠),π‘¦π‘š(𝑠))𝑑𝑠𝑑𝑠 𝑑 βˆ’βˆž βˆ’βˆ« (𝑑 βˆ’π‘ )π›Όβˆ’1 Ξ“(𝛼) 𝑑 0 (∫ 𝐾(𝑑,𝑠)𝐹(𝑑,𝑠,π‘₯π‘š(𝑠),π‘¦π‘š(𝑠))𝑑𝑠)𝑑𝑠 𝑑 βˆ’βˆž + 𝑏1𝑑 π›Όβˆ’1 Ξ“(Ξ±) βˆ’ π‘‘π›Όβˆ’1 Ξ“(𝛼) ∫ 1 0 ∫ 𝐾(𝑑,𝑠)𝐹(𝑑,𝑠,π‘₯ (𝑠),𝑦 (𝑠))𝑑𝑠𝑑𝑠 𝑑 βˆ’βˆž + ∫ (𝑑 βˆ’ 𝑠)π›Όβˆ’1 Ξ“(𝛼) 𝑑 0 (∫ 𝐾(𝑑,𝑠)𝐹(𝑑,𝑠,π‘₯ (𝑠),𝑦 (𝑠))𝑑𝑠)𝑑𝑠 𝑑 βˆ’βˆž βˆ’ 𝑏1𝑑 π›Όβˆ’1 Ξ“(Ξ±) β€– ≀ π‘‘π›Όβˆ’1 Ξ“(𝛼) ∫ βˆ«π›Ώ1𝑒 βˆ’πœ†1(π‘‘βˆ’π‘ )‖𝐹(𝑑,𝑠,π‘₯π‘š(𝑠),π‘¦π‘š(𝑠))βˆ’πΉ(𝑑,𝑠,π‘₯ (𝑠),𝑦 (𝑠))‖𝑑𝑠𝑑𝑠 𝑑 βˆ’βˆž 1 0 βˆ’βˆ« (𝑑 βˆ’π‘ )π›Όβˆ’1 Ξ“(𝛼) 𝑑 0 (∫ 𝛿1𝑒 βˆ’πœ†1(π‘‘βˆ’π‘ )‖𝐹(𝑑,𝑠,π‘₯π‘š(𝑠),π‘¦π‘š(𝑠)) 𝑑 βˆ’βˆž βˆ’πΉ(𝑑,𝑠,π‘₯ (𝑠),𝑦 (𝑠))‖𝑑𝑠)𝑑𝑠 ≀ 𝐿1𝛿1(𝛼𝑑 π›Όβˆ’1 βˆ’ 𝑑𝛼) πœ†1Ξ“(𝛼+ 1) (β€–π‘₯π‘š βˆ’ π‘₯ β€–+ β€–π‘¦π‘š βˆ’ 𝑦 β€–) And for the function y(t,𝑦0) we have β€– π‘‘π›½βˆ’1 Ξ“(𝛽) ∫ 1 0 ∫ 𝐺(𝑑,𝑠)𝐻(𝑑,𝑠,π‘₯π‘š(𝑠),π‘¦π‘š(𝑠))𝑑𝑠𝑑𝑠 𝑑 βˆ’βˆž βˆ’βˆ« (𝑑 βˆ’π‘ )π›½βˆ’1 Ξ“(𝛽) 𝑑 0 (∫ 𝐺(𝑑,𝑠)𝐻(𝑑,𝑠,π‘₯π‘š(𝑠),π‘¦π‘š(𝑠))𝑑𝑠)𝑑𝑠 𝑑 βˆ’βˆž + 𝑏2𝑑 π›½βˆ’1 Ξ“(Ξ²) βˆ’ π‘‘π›½βˆ’1 Ξ“(𝛽) ∫ 1 0 ∫ 𝐺(𝑑,𝑠)𝐻(𝑑,𝑠,π‘₯ (𝑠),𝑦 (𝑠))𝑑𝑠𝑑𝑠 𝑑 βˆ’βˆž +∫ (𝑑 βˆ’π‘ )π›½βˆ’1 Ξ“(𝛽) 𝑑 0 (∫ 𝐺(𝑑,𝑠)𝐻(𝑑,𝑠,π‘₯ (𝑠),𝑦 (𝑠))𝑑𝑠)𝑑𝑠 𝑑 βˆ’βˆž βˆ’ 𝑏2𝑑 π›½βˆ’1 Ξ“(Ξ²) β€– F. Y. Ishak Existence Solution for Nonlinear System of Fractional Integrodifferential Equations of Volterra Type with Fractional Boundary Conditions 9 ≀ 𝐿2𝛿2(𝛽𝑑 π›½βˆ’1 βˆ’ 𝑑𝛽) πœ†2Ξ“(𝛽+ 1) (β€–π‘₯π‘š βˆ’ π‘₯ β€–+ β€–π‘¦π‘š βˆ’π‘¦ β€–) And since the sequences: {π‘₯π‘š(𝑑,π‘₯0)}π‘š=0 ∞ , {π‘¦π‘š(𝑑,𝑦0)}π‘š=0 ∞ uniformly convergence to π‘₯ (𝑑,π‘₯0), 𝑦 (𝑑,𝑦0) respectively on the interval [0,1] ,that is (3.7),(3.8) satisfies. Theorem (3.2): If all conditions and assumptions of theorem (3.1) satisfied, then the functions π‘₯ (𝑑,π‘₯0), 𝑦(𝑑,𝑦0) are unique solution for system (1.1) on domain (1.2). Proof: let ( 𝑒 (𝑑,𝑒0) 𝑀 (𝑑,𝑀0) ) = ( π‘‘π›Όβˆ’1 Ξ“(𝛼) ∫ 1 0 ∫ 𝐾(𝑑,𝑠)𝐹(𝑑,𝑠,𝑒 (𝑠),𝑀 (𝑠))𝑑𝑠𝑑𝑠 𝑑 βˆ’βˆž βˆ’ ∫ (π‘‘βˆ’π‘ )π›Όβˆ’1 Ξ“(𝛼) 𝑑 0 (∫ 𝐾(𝑑,𝑠)𝐹(𝑑,𝑠,𝑒 (𝑠),𝑀 (𝑠))𝑑𝑠)𝑑𝑠 𝑑 βˆ’βˆž + 𝑏1𝑑 π›Όβˆ’1 Ξ“(Ξ±) π‘‘π›½βˆ’1 Ξ“(𝛽) ∫ 1 0 ∫ 𝐺(𝑑,𝑠)𝐻(𝑑,𝑠,𝑒 (𝑠),𝑀 (𝑠))𝑑𝑠𝑑𝑠 𝑑 βˆ’βˆž βˆ’ ∫ (π‘‘βˆ’π‘ )π›½βˆ’1 Ξ“(𝛽) 𝑑 0 (∫ 𝐺(𝑑,𝑠)𝐻(𝑑,𝑠,𝑒 (𝑠),𝑀 (𝑠))𝑑𝑠)𝑑𝑠 𝑑 βˆ’βˆž + 𝑏2𝑑 π›½βˆ’1 Ξ“(Ξ²) ) be another solution for system (1.1) then: β€–π‘₯ (𝑑,π‘₯0)βˆ’π‘’(𝑑,𝑒0)β€– ≀ π‘‘π›Όβˆ’1 Ξ“(𝛼) ∫ 1 0 ∫ ‖𝐾(𝑑,𝑠)‖‖𝐹(𝑑,𝑠,π‘₯ (𝑠),𝑦 (𝑠))βˆ’ 𝑑 βˆ’βˆž 𝐹(𝑑,𝑠,𝑒 (𝑠),𝑀 (𝑠))β€–π‘‘π‘ π‘‘π‘ βˆ’ ∫ (π‘‘βˆ’π‘ )π›Όβˆ’1 Ξ“(𝛼) 𝑑 0 (∫ ‖𝐾(𝑑,𝑠)‖‖𝐹(𝑑,𝑠,π‘₯ (𝑠),𝑦 (𝑠))βˆ’ 𝑑 βˆ’βˆž 𝐹(𝑑,𝑠,𝑒 (𝑠),𝑀 (𝑠))‖𝑑𝑠)𝑑𝑠 ≀ 𝐿1𝛿1(𝛼𝑑 π›Όβˆ’1 βˆ’π‘‘π›Ό) πœ†1Ξ“(𝛼 +1) (β€–π‘₯ βˆ’ 𝑒 β€– +‖𝑦 βˆ’π‘€ β€–) And ‖𝑦 (𝑑,𝑦0)βˆ’π‘€(𝑑,𝑀0)β€– ≀ π‘‘π›Όβˆ’1 Ξ“(𝛼) ∫ 1 0 ∫ ‖𝐺(𝑑,𝑠)‖‖𝐻(𝑑,𝑠,π‘₯ (𝑠),𝑦 (𝑠))βˆ’ 𝑑 βˆ’βˆž 𝐻(𝑑,𝑠,𝑒 (𝑠),𝑀 (𝑠))β€–π‘‘π‘ π‘‘π‘ βˆ’ ∫ (π‘‘βˆ’π‘ )π›Όβˆ’1 Ξ“(𝛼) 𝑑 0 (∫ ‖𝐺(𝑑,𝑠)‖‖𝐻(𝑑,𝑠,π‘₯ (𝑠),𝑦 (𝑠))βˆ’ 𝑑 βˆ’βˆž 𝐻(𝑑,𝑠,𝑒 (𝑠),𝑀 (𝑠))‖𝑑𝑠)𝑑𝑠 ≀ 𝐿2𝛿2(𝛽𝑑 π›½βˆ’1 βˆ’π‘‘π›½) πœ†2Ξ“(𝛽 + 1) (β€–π‘₯ βˆ’π‘’ β€–+ β€–π‘¦βˆ’ 𝑀 β€–) Rewrite in vector form: ( β€–π‘₯ (𝑑,π‘₯0)βˆ’π‘’(𝑑,𝑒0)β€– ‖𝑦 (𝑑,𝑦0)βˆ’w(𝑑,𝑀0)β€– ) ≀ Ξ”(𝑑)( β€–π‘₯(𝑑)βˆ’π‘’(𝑑)β€– ‖𝑦 (𝑑)βˆ’ 𝑀(𝑑)β€– ) (3.9) By take the maximum value for both sides of (3.9) and reputation it we get: ( β€–π‘₯ (𝑑,π‘₯0)βˆ’π‘’(𝑑,𝑒0)β€– ‖𝑦 (𝑑,𝑦0)βˆ’w(𝑑,𝑀0)β€– ) ≀ Ξ”0 π‘š ( β€–π‘₯(𝑑)βˆ’π‘’(𝑑)β€– ‖𝑦 (𝑑)βˆ’ 𝑒(𝑑)β€– ) (3.10) From (3.9) and condition (1.8) we have 𝐴0 π‘š β†’ 0 when π‘š β†’ ∞ that is: π‘₯ (𝑑,π‘₯0) = 𝑒(𝑑,𝑒0) and 𝑦 (𝑑,𝑦0)βˆ’ w(𝑑,𝑀0) Therefor π‘₯ (𝑑,π‘₯0), 𝑦(𝑑,𝑦0) is a unique solution for system (1.1). Jurnal Matematika MANTIK Volume 6, Issue. 1, May 2020, pp. 1-12 10 Theorem (3.3): Under the hypothesis and conditions of theorem (3.1) if οΏ½ΜƒοΏ½(𝑑,π‘₯0), οΏ½ΜƒοΏ½(𝑑,𝑦0) is any other solution of system (1.1), then the solution is stable if satisfies the inequality: ( β€–π‘₯ (𝑑,π‘₯0)βˆ’οΏ½ΜƒοΏ½(𝑑,π‘₯0)β€– ‖𝑦 (𝑑,𝑦0)βˆ’οΏ½ΜƒοΏ½(𝑑,𝑦0)β€– ) ≀ ( πœ–1 πœ–2 ) Where: οΏ½ΜƒοΏ½(𝑑,π‘₯0) = π‘‘π›Όβˆ’1 Ξ“(𝛼) ∫ 1 0 ∫ 𝐾(𝑑,𝑠)𝐹(𝑑,𝑠, οΏ½ΜƒοΏ½ (𝑠),οΏ½ΜƒοΏ½ (𝑠))𝑑𝑠𝑑𝑠 𝑑 βˆ’βˆž βˆ’ ∫ (π‘‘βˆ’π‘ )π›Όβˆ’1 Ξ“(𝛼) 𝑑 0 (∫ 𝐾(𝑑,𝑠)𝐹(𝑑,𝑠, οΏ½ΜƒοΏ½ (𝑠), οΏ½ΜƒοΏ½ (𝑠))𝑑𝑠)𝑑𝑠 𝑑 βˆ’βˆž + 𝑏1𝑑 π›Όβˆ’1 Ξ“(Ξ±) οΏ½ΜƒοΏ½(𝑑,𝑦0) = π‘‘π›½βˆ’1 Ξ“(𝛽) ∫ 1 0 ∫ 𝐺(𝑑,𝑠)𝐻(𝑑,𝑠, οΏ½ΜƒοΏ½ (𝑠), οΏ½ΜƒοΏ½(𝑠))𝑑𝑠𝑑𝑠 𝑑 βˆ’βˆž βˆ’ ∫ (π‘‘βˆ’π‘ )π›½βˆ’1 Ξ“(𝛽) 𝑑 0 (∫ 𝐺(𝑑,𝑠)𝐻(𝑑,𝑠, οΏ½ΜƒοΏ½ (𝑠), οΏ½ΜƒοΏ½ (𝑠))𝑑𝑠)𝑑𝑠 𝑑 βˆ’βˆž + 𝑏2𝑑 π›½βˆ’1 Ξ“(Ξ²) Proof: β€–π‘₯(𝑑,π‘₯0) βˆ’οΏ½ΜƒοΏ½(𝑑,π‘₯0)β€– ≀ 𝐿1𝛿1(𝛼𝑑 π›Όβˆ’1βˆ’π‘‘π›Ό) πœ†1Ξ“(𝛼+1) (β€–π‘₯ βˆ’οΏ½ΜƒοΏ½β€–+ ‖𝑦 βˆ’οΏ½ΜƒοΏ½β€–) ‖𝑦(𝑑,𝑦0)βˆ’οΏ½ΜƒοΏ½ (𝑑,𝑦0)β€– ≀ 𝐿2𝛿2(𝛽𝑑 π›½βˆ’1βˆ’π‘‘π›½) πœ†2𝛀(𝛽+1) (β€–π‘₯ βˆ’οΏ½ΜƒοΏ½β€–+ β€–π‘¦βˆ’ οΏ½ΜƒοΏ½ β€–) Rewrite (3.11), (3.12) in victor form we get: ( β€–π‘₯(𝑑,π‘₯0)βˆ’ οΏ½ΜƒοΏ½(𝑑,π‘₯0)β€– ‖𝑦(𝑑,𝑦0)βˆ’οΏ½ΜƒοΏ½ (𝑑,𝑦0)β€– ) ≀ Ξ”(𝑑)( β€–π‘₯(𝑑) βˆ’οΏ½Μ…οΏ½(𝑑)β€– ‖𝑦(𝑑) βˆ’οΏ½Μ…οΏ½(𝑑)β€– ) By condition (1.8) and for πœ–1,πœ–2 β‰₯ 0 we have: ( β€–π‘₯(𝑑,π‘₯0)βˆ’ οΏ½ΜƒοΏ½(𝑑,π‘₯0)β€– ‖𝑦(𝑑,𝑦0)βˆ’ οΏ½ΜƒοΏ½ (𝑑,𝑦0)β€– ) ≀ ( πœ–1 πœ–2 ) (3.13) By the definition of stability, we find that οΏ½ΜƒοΏ½(𝑑,π‘₯0), οΏ½ΜƒοΏ½ (𝑑,𝑦0) is stable solution for system (1.1) Example (3.1): consider the following system of fractional integrodifferential equations: 𝐷4 3⁄ π‘₯(𝑑) = ∫ (4𝑒2𝑠 +1) 𝑑 βˆ’βˆž π‘₯(𝑠) 𝑦(𝑠) 𝑑𝑠 𝐷3 2⁄ 𝑦(𝑑) = ∫ 3cos (2𝑠)(𝑦(𝑠) 𝑑 βˆ’βˆž + 𝑠𝑖𝑛(π‘₯(𝑠)))𝑑𝑠 𝐷1 3⁄ π‘₯(0) = 0, 𝐷1 3⁄ π‘₯(1) = 2, 𝐷1 2⁄ π‘₯(0) = 0, 𝐷1 2⁄ π‘₯(1) = 3 Comparing (3.14) and (1.1) we see that, 𝛼 = 4 3⁄ ,𝛽 = 3 2⁄ ,π‘˜(𝑑,𝑠) = (4𝑒2𝑠 + 1),𝐺(𝑑,𝑠) = 3cos (2𝑠) 𝐹(𝑑,𝑠,π‘₯(𝑠),𝑦(𝑠)) = π‘₯(𝑠) 𝑦(𝑠)⁄ ,𝐻(𝑑,𝑠,π‘₯(𝑠),𝑦(𝑠)) = 𝑦(𝑠) +sin(π‘₯(𝑠)) , if we choose 𝑀1 = 1, 𝑀2 = 1,𝐿1 = 2𝑀1,𝐿2 = 2𝑀2, 𝛿1 = 1,𝛿2 = 2,πœ†1 = 2,πœ†2 = 3,then (1.3)βˆ’ (1.6) holds and ∢ (3.11) (3.12) (3.14) F. Y. Ishak Existence Solution for Nonlinear System of Fractional Integrodifferential Equations of Volterra Type with Fractional Boundary Conditions 11 πœ† π‘šπ‘Žπ‘₯(Ξ”0) = 𝐿1𝛿1(𝛼 βˆ’1) πœ†1Ξ“(𝛼 + 1) + 𝐿2𝛿2(π›½βˆ’1) πœ†2Ξ“(𝛽+1) = (2)(1)(4 3⁄ βˆ’1) (2)( 1.1906) + (2)(2)(3 2βˆ’ 1)⁄ (3)( 1.3293) < 1 Thus, by Theorems (3.1) -(3.3), we obtain that (1.1) has a unique stability solution. 4. Conclusions The article presented some existence and uniqueness results for a boundary value problem of fractional integro-differential system. The prove of the theorems based on two basic conditions (1.8), (3.1). The basic of fractional differentiation were used to find the solution formula. The idea of existence and uniqueness theorem is the basis for finding results. The present work can be extended to boundary value problem with nonlocal and nonseparated fractional boundary conditions. References [1] Podlubny, I: Fractional differential equations, mathematics in science and engineering. 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