Abstract
A new impulsive multi-orders fractional differential equation is studied. The existence and uniqueness results are obtained for a nonlinear problem with fractional integral boundary conditions by applying standard fixed point theorems. An example for the illustration of the main result is presented.
1. Introduction
Nowadays, fractional differential equations have attracted a lot of attention due to its wide range of applications in many practical problems such as in physics, engineering, economics, and so on; see [1–5].
Impulsive differential equations have extensively been studied in the past two decades. Indeed impulsive differential equations are used to describe the dynamics of processes in which sudden, discontinuous jumps occur. Such processes are naturally seen in harvesting, earthquakes, diseases, and so forth. Recently, fractional impulsive differential equations have attracted the attention of many researchers. For the general theory and applications of such equations we refer the interested reader to see [6–24] and the references therein.
In this paper, we investigate a new impulsive nonlinear differential equation involving multi-orders fractional derivatives and deviating argument. Precisely, we consider the following multipoint fractional integral boundary value problem: where is the Caputo fractional derivative of order and is fractional Riemann-Liouville integral of order , , , , deviating argument , , , , and , where and denote the right and the left limits of at , respectively. have a similar meaning for .
The paper is organized as follows. Section 2 gives some definitions and necessary lemmas, while the main results are presented in Section 3.
2. Preliminaries
Let us fix , , and with and introduce a Banach space: with the norm .
For the reader’s convenience, we present some necessary definitions from fractional calculus theory and lemmas.
Definition 1. The Riemann-Liouville fractional integral of order for a function is defined as provided the integral exists.
Definition 2. The Caputo fractional derivative of order for a function is defined by where denotes the integer part of real number .
Lemma 3. For a given , a function is a solution of the following impulsive boundary value problem: if and only if is a solution of the impulsive fractional integral equation where
Proof. Let be a solution of (5). For any , we have
for some . Differentiating (8), we get
If , then
for some . Thus,
Using the impulse conditions
we find that
Consequently,
By a similar process, we can get
The boundary condition implies . For , we have
Applying the boundary condition , then
Substituting the value of in (8) and (15), we obtain (6). Conversely, assume that is a solution of the impulsive fractional integral equation (6); then by a direct computation, it follows that the solution given by (6) satisfies (5). This completes the proof.
3. Main Results
Define an operator by
Notice that problem (1) has a solution if and only if the operator has a fixed point.
For convenience, we will give some notations:
Theorem 4. Assume the following. (H1)There exists a nonnegative function such that where are nonnegative constants.(H2)There exist positive constants and such that Then problem (1) has at least one solution.
Proof. Firstly, we will prove that is a completely continuous operator. Obviously, the continuity of functions , , and ensures the continuity of operator .
Let be bounded. Then, there exist positive constants such that , and for all . Thus, for any , we have
which implies
On the other hand, for any , , we have
Hence, for with and , we have
This implies that is equicontinuous on all . Consequently, Arzela-Ascoli theorem ensures the operator is a completely continuous operator.
Next, we will show that the operator maps into . For that, let us choose and define a ball . For any , by the conditions (H1) and (H2), we have
Thus,
This implies . Hence, we conclude that is completely continuous. It follows from the Schauder fixed point theorem that the operator has at least one fixed point. That is, problem (1) has at least one solution in .
Theorem 5. Suppose that there exist a nonnegative function and nonnegative constants such that for , and . Furthermore, the assumption holds. Then problem (1) has a unique solution.
Proof. For , we have As , we have . Therefore, is a contraction. It follows from the Banach contraction mapping principle that problem (1) has a unique solution.
Example 6. For , , , , , , , , , , and , we consider the following impulsive multi-orders fractional differential equation: Observe that Clearly, , , , , and and the conditions of Theorem 4 hold. Thus, by Theorem 4, the impulsive multi-orders fractional boundary value problem (30) has at least one solution.
Conflict of Interests
The authors declare that they have no conflict of interests.
Authors’ Contribution
All authors have equal contributions.
Acknowledgments
This work is supported by the NNSF of China (no. 61373174) and the Natural Science Foundation for Young Scientists of Shanxi Province, China (no. 20120211002-3).