Qualitative Analysis of Implicit Dirichlet Boundary Value Problem for Caputo-Fabrizio Fractional Differential Equations
Abstract
This article studies a class of implicit fractional differential equations involving a Caputo-Fabrizio fractional derivative under Dirichlet boundary conditions (DBCs). Using classical fixed-point theory techniques due to Banch’s and Krasnoselskii, a qualitative analysis of the concerned problem for the existence of solutions is established. Furthermore, some results about the stability of the Ulam type are also studied for the proposed problem. Some pertinent examples are given to justify the results.
1. Introduction and Preliminaries
Throughout the paper, C[I, R] is a Banach space with norm ‖z‖ = maxw∈I|z(w)|.
Definition 1 (see [24].)For any z(w) ∈ C[I, R], we defined the derivative of Caputo-Fabrizio for nonsingular kernel as
Definition 2 (see [24].)The integral of Caputo-Fabrizio for nonsingular kernel type is given by
Definition 3 (see [25].)Let n < μ ≤ n + 1 and f be such that f(n) ∈ H1(c, d). Set α = μ − n. Then, α ∈ [0, 1] and we define
Lemma 4. For z(w) defined on [c, d] and μ ∈ [n, n + 1], for some n ∈ N0, we have
2. Results and Discussion
In this part, we investigate the solution of the proposed problem (1) and also study the uniqueness and existence of the solutions.
Lemma 5. The solution of
Proof. Let z(w) be a solution to problem (6). Applying Caputo-Fabrizio integral on both sides and then using Lemma 4 and Definition 3, we have
Using boundary conditions z(c) = z(d) = 0, we have
Putting c0, c1 in (9), we get
For simplification, use some notations; we use and give the solution of (1) as bellow.
Corollary 6. In view of 6, the solution of the considered problem (1) is given by
Further, for the existence and uniqueness of the solution of problem (1), we use some fixed point theorems. For this, we need to define an operator as N : C[I, R] → C[I, R] by
To proceed further, using Corollary (6) to convert the proposed problem (1) is to a fixed point problem as Nz(w) = z(w), where the operator N is given by (13). Therefore, Problem (1) has a solution if and only if the operator N has a fixed point, where λ(w) = f(w, z(w), λ(w)) and . We assume that
(H1) There exist certain constant Df > 0 and 0 < Ef < 1, such that
Theorem 7. Under the hypothesis (H1), the mentioned problem (1) has a unique solution if
Proof. Suppose we have
Repeating the above process, we get
Applying maximum on both sides, we have
Thus, operator N is a contraction; therefore, the operator N has a unique fixed point. Hence, the corresponding problem (1) has a unique solution.
Our next result is to show the existence of the solution to the proposed problem (1) which is based on Krasnoselskii’s fixed-point theorem. Therefore, the given hypothesis hold.
Theorem 8 (see [26].)Let H ⊂ C[I, R] be a closed, convex nonempty subset of C[I, R]; then, there exist N1, N2 operators such that
- (1)
N1z1 + N2z2 ∈ H for all z1, z2 ∈ H
- (2)
N1 is a contraction, and N2 is compact and continuous
Then, there exist at least one solution z ∈ H such that N1z + N2z = z.
Theorem 9. If the hypothesis (H2) is satisfied, then (1) has at least one solution if
Proof. Suppose we define two operators from (13) as
Let us define a set F = {z ∈ C[I, R]: ∥z∥≤r}, since f is continuous, so we show that the operator N1 is contraction. For this we have
Hence, N1 is contraction. Next, to prove that the operator N2 is compact and continuous, for this z(w) ∈ C[I, R], we have
Now, using (28) in (26) and then taking the maximum on both sides, we have
Which implies that
Therefore, N2 is bounded. Next, let w1 < w2 in I, we have
Now, using (28) in (31), we have
Applying maximum on right-hand side of the above inequality, we take
Obviously, from (33), we see that w1 → w2; then, the right-hand side of (33) goes to zero, so ∣N2z(w2) − N2z(w1) | →0 as w1 → w2. Hence, the operator N2 is continuous. Also, N(H) ⊂ H; therefore, the operator N2 is compact, and by the Arzela-Ascoli theorem, the operator N has at least one fixed point. Therefore, the mentioned problem (1) has at least one solution.
3. Stability Theory
In this portion, we develop several consequences concerning the stability of Hyers-Ulam and generalize Hyers-Ulam type. Before progressing further, we provide various notions and definitions:
Definition 10. The proposed problem (1) is Hyers-Ulam stable if at any ε > 0 for the given inequality
Further, the considered problem (1) will generalize Hyers-Ulam stable if there exists nondecreasing function ϕ : (c, d) → (0, ∞) such that
Also, we state an important remark as:
Remark 11. Let there exist a function ψ(w) which depends on z ∈ C[I, R] with ψ(c) = 0 and ψ(d) = 0 such that
Lemma 12. The solution of the given proposed problem
Proof. The solution of (39) can be acquired straightforward by using Lemma 5. Although from the solution, it is clear to become result (40) by using Remark 11.
Theorem 13. Under the Lemma 12, the solution of the proposed problem (1) is Hyers-Ulam stable and also generalized Hyers-Ulam stable if
Proof. Let z(w) ∈ C[I, R] be any solution of the considered problem (1) and be a unique solution of the said problem; then, we take,
Using (40) and (18) in the above inequality, then taking maximum on both sides, we have
Hence, from the above inequality, we have
Therefore, the solution is Hyers-Ulam stable. Further, let
4. Examples of Our Analysis
In this part of our analysis, we justify certain obtained results through some counter examples which are given below.
Example 14. Suppose, we take the boundary value problem of implicit type as
Clearly, c = 0, d = 1 and is a continuous function for all x ∈ [0, 1]. Further, suppose that ; then, we consider as
which implies that
Since from (48), one has Df = 1/55, Ef = 1/55, and μ = 1/3. Further, also consider
Therefore, pf = 1/35, qf = 1/55, rf = 1/55. and Gμ = 1/3, , c = 0, and d = 1. Then
Therefore, the conditions of Theorem 7 are satisfied. Thus, the problem (46) has a unique solution. Further, we need to satisfy some conditions of theorem (9).
Hence, the conditions of Theorem 9 also hold. Therefore, (46) has at least one solution. Furthermore, proceed to verify the stability results; we see that
Hence, the solution of the mentioned problem (46) is Hyers-Ulam stable and consequently generalized Hyers-Ulam stable.
Example 15. Take another boundary value problem of implicit type as
Clearly c = 0, d = 1 and is a continuous function for all w ∈ [0, 1]. Further let , then consider, we have
Thus from (55), one has Df = 1/45, Ef = 3/65, and μ = 3/7. And also consider we have
Therefore, the conditions of Theorem 7 are satisfied. Thus, the problem (53) has a unique solution. Further, we need to satisfy some conditions of Theorem (9), we have
Hence, the conditions of Theorem (9) also hold. Therefore, (53) has at least one solution. Furthermore, proceed to verify stability results; we see that
Hence, the solution of the mentioned problem (53) is Hyers-Ualm stable and consequently generalized Hyers-Ulam stable.
5. Conclusion
We have successfully attained several essential conditions consistent to existence theory and stability theory for implicit type problem of DBCs with involving Caputo-Fabrizio fractional operator. By classical fixed point theory, we used some fixed point theorem like Krasnoselskii’s fixed-point and Banach’s contraction. Further, we studied certain stability results of Hyers-Ulam and generalized Hyers-Ulam stability. By appropriate illustrations, we have established the obtained investigation.
Conflicts of Interest
The authors declare that they have no competing interest regarding this manuscript.
Authors’ Contributions
All authors contribute equally to the writing of this manuscript. All authors read and approve the final version.
Acknowledgments
The authors are grateful to the editorial board and anonymous reviewers for their comments and remarks which helped to improve this manuscript. The third author would like to thank Prince Sultan University for funding this work through research group Nonlinear Analysis Methods in Applied Mathematics (NAMAM) group number RG-DES-2017-01-17.
Open Research
Data Availability
No data were used to support this study.