Hindawi Publishing Corporation Advances in Difference Equations Volume 2011, Article ID 404917, 16 pages doi:10.1155/2011/404917 Research Article Nonlocal Boundary Value Problem for Impulsive Differential Equations of Fractional Order Liu Yang1, 2 and Haibo Chen1 1 2 Department of Mathematics, Central South University, Changsha, Hunan 410075, China Department of Mathematics and Computational Science, Hengyang Normal University, Hengyang, Hunan 421008, China Correspondence should be addressed to Liu Yang, yangliu19731974@yahoo.com.cn Received 18 September 2010; Accepted 4 January 2011 Academic Editor: Mouffak Benchohra Copyright q 2011 L. Yang and H. Chen. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. We study a nonlocal boundary value problem of impulsive fractional differential equations. By means of a fixed point theorem due to O’Regan, we establish sufficient conditions for the existence of at least one solution of the problem. For the illustration of the main result, an example is given. 1. Introduction Fractional differential equations arise in many engineering and scientific disciplines as the mathematical modeling of systems and processes in various fields, such as physics, mechanics, aerodynamics, chemistry, and engineering and biological sciences, involves derivatives of fractional order. Fractional differential equations also provide an excellent tool for the description of memory and hereditary properties of many materials and processes. In consequence, fractional differential equations have emerged as a significant development in recent years, see 1–3. As one of the important topics in the research differential equations, the boundary value problem has attained a great deal of attention from many researchers, see 4–11 and the references therein. As pointed out in 12, the nonlocal boundary condition can be more useful than the standard condition to describe some physical phenomena. There are three noteworthy papers dealing with the nonlocal boundary value problem of fractional differential equations. Benchohra et al. 12 investigated the following nonlocal boundary value problem c Dα ut ft, ut 0, u0 gu, 0 < t < T, 1 < α ≤ 2, uT uT , where c Dα denotes the Caputo’s fractional derivative. 1.1 2 Advances in Difference Equations Zhong and Lin 13 studied the following nonlocal and multiple-point boundary value problem c Dα ut ft, ut 0, u0 u0 gu, 0 < t < 1, 1 < α ≤ 2, u 1 u1 m−2 bi u ξi . 1.2 i1 Ahmad and Sivasundaram 14 studied a class of four-point nonlocal boundary value problem of nonlinear integrodifferential equations of fractional order by applying some fixed point theorems. On the other hand, impulsive differential equations of fractional order play an important role in theory and applications, see the references 15–21 and references therein. However, as pointed out in 15, 16, the theory of boundary value problems for nonlinear impulsive fractional differential equations is still in the initial stages. Ahmad and Sivasundaram 15, 16 studied the following impulsive hybrid boundary value problems for fractional differential equations, respectively, Dq ut ft, ut 0, 1 < q ≤ 2, t ∈ J1 0, 1 \ t1 , t2 , . . . , tp , Δutk Ik u t−k , Δu tk Jk u t−k , tk ∈ 0, 1, k 1, 2, . . . , p, c u0 u 0 0, 1.3 u1 u 1 0, Dq ut ft, ut 0, 1 < q ≤ 2, t ∈ J1 0, 1 \ t1 , t2 , . . . , tp , Δutk Ik u t−k , Δu tk Jk u t−k , tk ∈ 0, 1, k 1, 2, . . . , p, 1 1 q1 usds, q2 usds. αu0 βu 0 αu1 βu 1 c 0 1.4 0 Motivated by the facts mentioned above, in this paper, we consider the following problem: Dq ut f t, ut, u t , 1 < q ≤ 2, t ∈ J1 0, 1 \ t1 , t2 , . . . , tp , Δutk Ik u t−k , Δu tk Jk u t−k , tk ∈ 0, 1, k 1, 2, . . . , p, c αu0 βu 0 g1 u, 1.5 αu1 βu 1 g2 u, where J 0, 1, f : J × Ê × Ê → Ê is a continuous function, and Ik , Jk : Ê → Ê are continuous functions, Δutk utk − ut−k with utk limh → 0 utk h, ut−k limh → 0− utk h, k 1, 2, . . . , p, 0 t0 < t1 < t2 < · · · < tp < tp1 1, α > 0, β ≥ 0, and g1 , g2 : PCJ, Ê → Ê are two continuous functions. We will define PCJ, Ê in Section 2. To the best of our knowledge, this is the first time in the literatures that a nonlocal boundary value problem of impulsive differential equations of fractional order is considered. Advances in Difference Equations 3 In addition, the nonlinear term ft, ut, u t involves u t. Evidently, problem 1.5 not only includes boundary value problems mentioned above but also extends them to a much wider case. Our main tools are the fixed point theorem of O’Regan. Some recent results in the literatures are generalized and significantly improved see Remark 3.6 The organization of this paper is as follows. In Section 2, we will give some lemmas which are essential to prove our main results. In Section 3, main results are given, and an example is presented to illustrate our main results. 2. Preliminaries At first, we present here the necessary definitions for fractional calculus theory. These definitions and properties can be found in recent literature. Definition 2.1 see 1–3. The Riemann-Liouville fractional integral of order α > 0 of a function y : 0, ∞ → Ê is given by α I0 yt 1 Γα t t − sα−1 ysds, 2.1 0 where the right side is pointwise defined on 0, ∞. Definition 2.2 see 1–3. The Caputo fractional derivative of order α > 0 of a function y : 0, ∞ → Ê is given by c Dα ut 1 Γn − α t t − sn−α−1 yn sds, 2.2 0 where n α1, α denotes the integer part of the number α, and the right side is pointwise defined on 0, ∞. Lemma 2.3 see 1–3. Let α > 0, then the fractional differential equation solutions ut c0 c1 t c2 t2 · · · cn−1 tn−1 , c Dq ut 0 has 2.3 where ci ∈ Ê, i 0, 1, . . . , n − 1, n q 1. Lemma 2.4 see 1–3. Let α > 0, then one has α c α I0 D ut ut c0 c1 t c2 t2 · · · cn−1 tn−1 , 2.4 where ci ∈ Ê, i 0, 1, . . . , n − 1, n q 1. Second, we define PCJ, Ê {x : J → Ê; x ∈ Ctk , tk1 , Ê, k 0, 1, . . . , p 1 and xtk , xt−k exist with xt−k xtk , k 1, . . . , p}. 4 Advances in Difference Equations PC1 J, Ê {x ∈ PCJ, Ê; x t ∈ Ctk , tk1 , Ê, k 0, 1, . . . , p 1, x tk , x t−k exist, and x is left continuous at tk , k 1, . . . , p}. Let C PC1 J, Ê; it is a Banach space with the norm x supt∈J {xtPC , x tPC }, where xPC supt∈J |xt|. Like Definition 2.1 in 16, we give the following definition. Definition 2.5. A function u ∈ C with its Caputo derivative of order q existing on J1 is a solution of 1.5 if it satisfies 1.5. To deal with problem 1.5, we first consider the associated linear problem and give its solution. Lemma 2.6. Assume that Ji Xt ⎧ ⎨t0 , t1 , i 0, ⎩ ti , ti1 , i 1, 2, . . . , p, ⎧ ⎨0, t ∈ J0 , ⎩ 1, t ∈ J0 . 2.5 For any σ ∈ C0, 1, the solution of the problem Dq ut σt, 1 < q ≤ 2, t ∈ J1 0, 1 \ t1 , t2 , . . . , tp , Δutk Ik u t−k , Δu tk Jk u t−k , tk ∈ 0, 1, k 1, 2, . . . , p, c αu0 βu 0 g1 u, αu1 βu 1 g2 u is given by ut t t − sq−1 σs ds Γ q ti 1 β β 1 1 − sq−2 σs 1 − sq−1 σs −t ds ds α α tp Γ q Γ q−1 tp 0<tk <1 tk tk−1 − tk − sq−1 σs ds Ik u tk Γ q tk β − tk − sq−2 σs 1 − tk ds Jk u tk α Γ q−1 tk−1 0<tk <1 2.6 Advances in Difference Equations tk tk − sq−1 σs − Xt ds Ik u tk Γ q tk−1 0<tk <t t k − tk − sq−2 σs Xt ds Jk u tk t − tk Γ q−1 tk−1 0<tk <t 1 αg1 u Xt αt − β g2 u − g1 u , 2 α 5 for t ∈ Ji , i 0, 1, . . . , p. 2.7 Proof. By Lemmas 2.3 and 2.4, the solution of 2.6 can be written as q ut I0 σt − b0 − b1 t t 0 t − sq−1 σsds − b0 − b1 t, Γ q t ∈ 0, t1 , 2.8 where b0 , b1 ∈ Ê. Taking into account that c Dq I0 ut ut, I0 I0 ut I0 ut for p, q > 0, we obtain q u t t 0 q p pq t − sq−2 σs ds − b1 . Γ q−1 2.9 Using αu0 βu 0 g1 u, we get ut t 0 β 1 t − sq−1 − t g1 u, σsds b1 α α Γ q t ∈ 0, t1 . 2.10 If t ∈ t1 , t2 , then we have ut t t1 t − sq−1 σs ds − c0 − c1 t − t1 , Γ q 2.11 where c0 , c1 ∈ Ê. In view of the impulse conditions Δut1 ut1 −ut−1 I1 ut−1 , Δu t1 u t1 − u t−1 J1 ut−1 , we have t1 β 1 t − sq−1 σs t1 − sq−1 σs − t g1 u I1 u t−1 ds ds b1 ut α α Γ q Γ q t1 0 t 1 − t1 − sq−2 σs , t ∈ t1 , t2 . ds J1 u t1 t − t1 Γ q−1 0 t 2.12 6 Advances in Difference Equations Repeating the process in this way, the solution ut for t ∈ tk , tk1 can be written as ut t β 1 t − sq−1 σs − t g1 u ds b1 α α Γ q tk tk tk − sq−1 σs − ds Ik u tk Γ q tk−1 0<tk <t t k − tk − sq−2 σs , ds Jk u tk t − tk Γ q−1 tk−1 0<tk <t 2.13 t ∈ tk , tk1 . Applying the boundary condition αu1 βu 1 g2 u, we find that b1 1 tp 1 − sq−1 σs ds Γ q β α 1 tp 0<tk <1 1 − sq−2 σs ds Γ q−1 t k tk−1 − tk − sq−1 σs ds Ik u tk Γ q 2.14 tk β − tk − sq−2 σs 1 − tk ds Jk u tk α Γ q−1 tk−1 0<tk <1 1 g1 u − g2 u . α Substituting the value of b1 into 2.10 and 2.13, we obtain 2.7. Now, we introduce the fixed point theorem which was established by O’Regan in 22. This theorem will be applied to prove our main results in the next section. Lemma 2.7 see 13, 22. Denote by U an open set in a closed, convex set Y of a Banach space E. Assume that 0 ∈ U. Also assume that FU is bounded and that F : U → Y is given by F F1 F2 , in which F1 : U → E is continuous and completely continuous and F2 : U → E is a nonlinear contraction (i.e., there exists a nonnegative nondecreasing function φ : 0, ∞ → 0, ∞ satisfying φz < z for z > 0, such that F2 x − F2 y ≤ φx − y for all x, y ∈ U, then either C1 F has a fixed point u ∈ U, or C2 there exists a point u ∈ ∂U and λ ∈ 0, 1 with u λFu, where U, ∂U represent the closure and boundary of U, respectively. Advances in Difference Equations 7 3. Main Results In order to apply Lemma 2.7 to prove our main results, we first give F, F1 , F2 as follows. Let Ωr {u ∈ C : u ≤ r}, r > 0, F1 ut t t − sq−1 fs, xs, x s ds Γ q ti 1 β β 1 1 − sq−2 fs, xs, x s 1 − sq−1 fs, xs, x s −t ds ds α α tp Γ q Γ q−1 tp tk tk − sq−1 fs, xs, x s − dsIk u tk Γ q tk−1 0<tk <1 tk β − tk − sq−2 fs, xs, x s 1 − tk dsJk u tk α Γ q−1 tk−1 0<tk <1 tk tk − sq−1 fs, xs, x s − Xt ds Ik u tk Γ q tk−1 0<tk <t t k − tk − sq−2 fs, xs, x s , ds Jk u tk Xt t − tk Γ q−1 tk−1 0<tk <t for t ∈ Ji , F2 ut 1 αg1 u Xt αt − β g2 u − g1 u , 2 α i 0, 1, . . . , p, for t ∈ Ji , i 0, 1, . . . , p, F F1 F2 . 3.1 Clearly, for any t ∈ Ji , i 0, 1, . . . , p, F1 u t F2 u t t t − sq−2 fs, xs, x s ds Γ q−1 ti 1 β 1 1 − sq−2 fs, xs, x s 1 − sq−1 fs, xs, x s − ds ds α tp Γ q Γ q−1 tp tk tk − sq−1 fs, xs, x s − ds Ik u tk Γ q tk−1 0<tk <1 tk β − tk −sq−2 fs, xs, x s 1 − tk ds Jk u tk α Γ q−1 tk−1 0<tk <1 tk tk − sq−2 fs, xs, x s − , Xt ds Jk u tk Γ q−1 tk−1 0<tk <t 1 Xt g2 u − g1 u . α Now, we make the following hypotheses. 3.2 8 Advances in Difference Equations A1 f : 0, 1 × Ê × Ê → Ê is continuous. There exists a nonnegative function pt ∈ C0, 1 with pt > 0 on a subinterval of 0, 1. Also there exists a nondecreasing function ψ : 0, ∞ → 0, ∞ such that |ft, u, v| ≤ ptψ|u| for any t, u, v ∈ 0, 1 × Ê × Ê. A2 There exist two positive constants l1 , l2 such that α β/α2 l1 l2 L < 1. Moreover, g1 0 0, g2 0 0, and g1 u − g1 v ≤ l1 u − v, A3 Ik , Jk : Ê → g2 u − g2 v ≤ l2 u − v, ∀u, v ∈ C. 3.3 Ê are continuous. There exists a positive constant M such that |Ik u| ≤ M, |Jk u| ≤ M, k 1, 2, . . . , p. 3.4 Let 2 β β 1 Mp 1 Mp 2pM, α α β 1 Mp pM, H2 Mp α 1 1 − sq−1 ps K1 ds Γ q 0 1 β β 1 1 − sq−2 ps 1 − sq−1 ps 1 ds ds α α tp Γ q Γ q−1 tp H1 tk tk tk − sq−1 ps β tk − sq−2 ps 1 ds ds α Γ q Γ q−1 tk−1 0<tk <1 tk−1 0<tk <1 tk tk − sq−2 ps tk tk − sq−1 ps ds ds, Γ q Γ q−1 0<tk <1 tk−1 0<tk <1 tk−1 1 β 1 1 − sq−2 ps 1 − sq−1 ps P ds ds K2 α tp Γ q Γ q Γ q−1 tp tk tk tk − sq−1 ps β tk − sq−2 ps 1 ds ds α Γ q Γ q−1 tk−1 0<tk <1 tk−1 0<tk <1 tk tk − sq−2 ps ds, Γ q−1 0<tk <1 tk−1 where P maxs∈0,1 ps. Now, we state our main results. 3.5 Advances in Difference Equations 9 Theorem 3.1. Assume that A1 , A2 , and A3 are satisfied; moreover, supr∈0,∞ r/H Kψr > 1/1 − L, where H max{H1 , H2 }, K max{K1 , K2 }, then the problem 1.5 has at least one solution. Proof. The proof will be given in several steps. Step 1. The operator F1 : Ωr → C is completely continuous. Let Mr maxs∈0,1 {|fs, xs, x s|, x ∈ Ωr }. In fact, by A1 , Mr can be replaced by P ψr. For any u ∈ Ωr , we have t − sq−1 fs, xs, x s ds |F1 ut| ≤ Γ q ti 1 1 − sq−1 fs, xs, x s β 1 ds α Γ q tp β 1 1 − sq−2 fs, xs, x s ds α tp Γ q−1 tk tk − sq−1 fs, xs, x s − ds Ik u tk Γ q tk−1 0<tk <1 β 1 − tk α 0<tk <1 t k − tk − sq−2 fs, xs, x s ds Jk u tk × Γ q−1 tk−1 tk tk − sq−1 fs, xs, x s − Xt ds Ik u tk Γ q tk−1 0<tk <t t k − tk − sq−2 fs, xs, x s Xt ds Jk u tk t − tk Γ q−1 tk−1 0<tk <t 1 1 − sq−1 ds ≤ Mr Γ q 0 1 1 β β 1 − sq−1 1 − sq−2 1 Mr ds Mr ds α α Γ q tp tp Γ q − 1 tk tk − sq−1 Mr ds M Γ q tk−1 0<tk <1 tk β tk − sq−2 Mr 1 ds M α Γ q−1 tk−1 0<tk <1 tk tk − sq−1 Mr ds M Γ q tk−1 0<tk <1 tk tk − sq−2 Mr ds M Γ q−1 tk−1 0<tk <1 t 10 Advances in Difference Equations β β 1 1 1 1 1 Mr ≤ Mr Mr p Mr M α α Γ q1 Γ q1 Γ q Γ q1 β 1 1 Mr p α Γ q M 1 1 p Mr M p Mr M , for t ∈ Ji , i 0, 1, . . . , p, Γ q1 Γ q t t − sq−2 fs, xs, x s F1 u t ≤ ds Γ q−1 ti 1 1 − sq−1 fs, xs, x s β 1 1 − sq−2 fs, xs, x s ds ds α tp Γ q Γ q−1 tp t k tk−1 0<tk <1 − tk − sq−1 fs, xs, x s ds Ik u tk Γ q tk β − tk − sq−2 fs, xs, x s 1 − tk ds Jk u tk α Γ q−1 tk−1 0<tk <1 Xt t k 0<tk <t 1 ≤ Mr Γ q tk−1 1 tp − tk − sq−2 fs, xs, x s ds Jk u tk Γ q−1 β 1 − sq−1 Mr ds α Γ q 0<tk <1 t k tk−1 1 tp 1 − sq−2 Mr ds Γ q−1 tk − sq−1 Mr ds M Γ q tk β tk − sq−2 Mr 1 − tk ds M α Γ q−1 tk−1 0<tk <1 tk tk − sq−2 Mr ds M Γ q−1 tk−1 0<tk <1 β 1 1 1 1 Mr p Mr M ≤ Mr Mr α Γ q Γ q1 Γ q Γ q1 β 1 1 Mr p α Γ q M 1 p Mr M , for t ∈ Ji , i 0, 1, . . . , p. Γ q 3.6 Advances in Difference Equations 11 These imply that F1 ut ≤ B, where B is a positive constant, that is, F1 is uniformly bounded. In addition, for any u ∈ Ωr , for all τ1 , τ2 ∈ Ji , τ1 < τ2 , we can obtain |F1 uτ1 − F1 uτ2 | τ2 τ2 − sq−1 fs, xs, x s ds ≤ Γ q τ1 τ1 τ2 − sq−1 − τ1 − sq−1 fs, xs, x s ds Γ q 0 1 1 − sq−1 fs, xs, x s ds τ2 − τ1 Γ q tp β 1 1 − sq−2 fs, xs, x s ds α tp Γ q−1 tk tk − sq−1 fs, xs, x s − ds Ik u tk Γ q tk−1 0<tk <1 tk β − tk − sq−2 fs, xs, x s 1 − tk ds Jk u tk α Γ q−1 tk−1 0<tk <1 t k − tk − sq−2 fs, xs, x s ds Jk u tk τ2 − τ1 Γ q−1 tk−1 0<tk <τ1 1 τ2 − τ1 q ≤ Mr Mr −τ2 − τ1 q τ2 q − τ1 q Γ q1 Γ q1 1 β 1 1 − sq−2 Mr 1 − sq−1 Mr τ2 − τ1 ds ds α tp Γ q − 1 Γ q tp tk tk − sq−1 Mr ds M Γ q tk−1 0<tk <1 tk β tk − sq−2 Mr 1 − tk ds M α Γ q−1 tk−1 0<tk <1 t k tk − sq−2 Mr τ2 − τ1 ds M , Γ q−1 tk−1 0<tk <τ1 F1 u τ1 − F1 u τ2 τ2 τ2 − sq−2 fs, xs, x s ≤ ds Γ q−1 τ1 τ1 τ1 − sq−2 − τ2 − sq−2 fs, xs, x s ds Γ q−1 ti ≤ τ2 − τ1 q−1 τ2 − τ1 q−1 τ1 − ti q−1 − τ2 − ti q−1 Mr . Mr Γ q Γ q 3.7 12 Advances in Difference Equations Taking into account the uniform continuity of the function tq , tq−1 on 0, 1, we get that F1 is equicontinuity on Ωr . By the Lemma 5.4.1 in 23, we have F1 Ωr as relatively compact. Due to the continuity of f, Ik , Jk , it is clear that F1 is continuous. Hence, we complete the proof of Step 1. Step 2. FU is bounded. From supr∈0,∞ r/H Kψr > 1/1 − L, it follows that there exists a positive constant r0 , such that r0 1 . > H Kψr0 1 − L 3.8 Now, we verify the validity of all the conditions in Lemma 2.6 with respect to the operator F1 , F2 , and F. Let Ωr0 U. From A2 , we have |F2 ut| ≤ ≤ 1 α1 − t β g1 u − g1 0 αt − βg2 u − g2 0 2 α 1 α β l1 r0 l2 r0 , α2 F2 u t 1 l2 r0 l1 r0 , α for t ∈ Ji , 3.9 for t ∈ Ji , i 0, 1, . . . , p. Combining with the property that F1 U is bounded Step 1, we have F bounded on U. Hence, we can assume that FU ≤ G, G > 0 is a constant. Step 3. F2 is a nonlinear contraction. Let Y Ωr1 , r1 max{G, r0 }, E C. By A2 , we obtain |F2 ut − F2 vt| ≤ 1/α2 |α1 − t βg1 u − g1 v| |αt − βg2 u − g2 v| ≤ α β/α2 l1 l2 u − v, and |F2 u t − F2 v t| ≤ 1/αl1 l2 u − v ≤ Lu − v, for t ∈ Ji . Since L < 1, we have F2 u − F2 v ≤ φu − v, that is, F2 is a nonlinear contraction φz Lz. Step 4. C2 in Lemma 2.7 does not occur. To this end, we perform the argument by contradiction. Suppose that C2 holds, then there exist λ ∈ 0, 1, u ∈ ∂Ωr0 , such that u λFu. Hence, we can obtain u r0 and |u| ≤ t t − sq−1 psψr0 ds Γ q ti 1 β 1 1 − sq−2 psψr0 β 1 − sq−1 psψr0 1 ds ds α α tp Γ q Γ q−1 tp tk tk − sq−1 psψr0 ds M Γ q tk−1 0<tk <1 tk β tk − sq−2 psψr0 1 − tk ds M α Γ q−1 tk−1 0<tk <1 Advances in Difference Equations tk tk − sq−1 psψr0 Xt ds M Γ q tk−1 0<tk <t 13 t k tk − sq−2 psψr0 ds M Xt t − tk Γ q−1 tk−1 0<tk <t 1 α β l1 r0 l2 r0 2 α 2 β β 1 1 Mp 1 Mp 2pM ≤ 2 α β l1 l2 r0 α α α ψr0 1 1 − sq−1 ps ds Γ q 0 β 1 α 1 tp 1 β 1 − sq−1 ps ds α Γ q tp 1 − sq−2 ps ds Γ q−1 tk tk − sq−1 ps ds Γ q 0<tk <1 tk−1 tk β tk − sq−2 ps 1 ds α Γ q−1 tk−1 0<tk <1 tk tk − sq−1 ps tk tk − sq−2 ps ds ds Γ q Γ q−1 0<tk <1 tk−1 0<tk <1 tk−1 ≤ Lr0 H1 K1 ψr0 , u ≤ t t − sq−2 psψr0 ds Γ q−1 ti 1 β 1 1 − sq−2 psψr0 1 − sq−1 psψr0 ds ds α tp Γ q Γ q−1 tp t 0<tk <1 k tk−1 tk − sq−1 psψr0 ds M Γ q tk β tk − sq−2 psψr0 1 − tk ds M α Γ q−1 tk−1 0<tk <1 Xt 0<tk <t ≤ t k tk−1 tk − sq−2 psψr0 ds M Γ q−1 β 1 α β 1 Mp pM l Mp r l 1 2 0 α α2 1 l1 r0 l2 r0 α 14 Advances in Difference Equations P ψr0 Γ q 1 tp β 1 − sq−1 ps ds α Γ q 1 tp 1 − sq−2 ps ds Γ q−1 tk tk − sq−1 ps ds Γ q 0<tk <1 tk−1 tk β tk − sq−2 ps 1 ds × α Γ q−1 tk−1 0<tk <1 tk tk − sq−2 ps ds Γ q−1 0<tk <1 tk−1 ≤ Lr0 H2 K2 ψr0 . 3.10 Therefore, r0 ≤ Lr0 H Kψr0 . However, it contradicts with 3.8. Hence, by using Steps 1–4, Lemmas 2.6 and 2.7, F has at least one fixed point u ∈ Ωr0 , which is the solution of problem 1.5. Next, we will give some corollaries. Corollary 3.2. Assume that A1 , A2 , and A3 are satisfied; moreover, lim supr∈0,∞ r/H Kψr ∞, where H max{H1 , H2 }, K max{K1 , K2 }; then the problem 1.5 has at least one solution. Assume that, A1 sublinear growth, f : 0, 1 × Ê × Ê → Ê is continuous. There exists a nonnegative function pt ∈ C0, 1 with pt > 0 on a subinterval of 0, 1. Also there exists a constant γ ∈ 0, 1, such that |ft, u, v| ≤ pt|u|γ for any t, u, v ∈ 0, 1 × Ê × Ê. Corollary 3.3. Assume that A1 , A2 , and A3 are satisfied, then the problem 1.5 has at least one solution. Assume that B1 f : 0, 1 × Ê → Ê is continuous. There exists a nonnegative function pt ∈ C0, 1 with pt > 0 on a subinterval of 0, 1. Also there exists a constant γ ∈ 0, 1 such that |ft, u| ≤ pt|u|γ for any t, u ∈ 0, 1 × Ê, B2 there exist two positive constants l1 , l2 such that α β/α2 l1 l2 L < 1. Moreover, q1 0 0, q2 0 0, and q1 u − q1 v ≤ l1 u − v, B3 Ik , Jk : Ê → q2 u − q2 v ≤ l2 u − v, ∀u, v ∈ C, 3.11 Ê are continuous. There exists a positive constant M, such that |Ik u| ≤ M, |Jk u| ≤ M, k 1, 2, . . . , p. 3.12 Advances in Difference Equations 15 Corollary 3.4. Assume that B1 , B2 , and B3 are satisfied, then the problem 1.4 has at least one solution. Assume that B1 f : 0, 1 × Ê → Ê is continuous. There exists a nonnegative function pt ∈ C0, 1 with pt > 0 on a subinterval of 0, 1. |ft, u| ≤ pt for any t, u ∈ 0, 1 × Ê. Corollary 3.5. Assume that B1 , B2 , and B3 are satisfied, then the problem 1.4 has at least one solution. Remark 3.6. Compared with Theorem 3.2 in 16, Corollary 3.5 does not need conditions ft, u − ft, v ≤ L1 u − v, Ik u − Ik V ≤ L2 u − v, and Jk u − Jk V ≤ L2 u − v. Moreover, we only need α β/α2 l1 l2 L < 1. Example 3.7. Consider the following problem: 1 0 < t < 1, t ∈ J1 0, 1 \ D , 2 1 u2 u2 1 , Δu , Δu 2 2 1 u2 2 u2 1 1 |us| |us| ds, u1 u 1 ds, u0 u 0 8 8 |us| |us| 0 0 c 3/2 ut θu sin u t , 2 2 3.13 where θ > 0. Here, α β 1, p 1, q 3/2. Let ps ≡ θ P and ψu u2 , then we can see that A1 holds. Choosing l1 l2 1/8, L 1/2, we can easily obtain√that A2 holds. Let √ H 8, K 4 26 2/3 πθ. Hence, M 1, then we have that A3 also holds. Moreover,√ √ we get supr∈0,∞ r/H Kψr 1/2 8θ4 26 2/3 π > 1/1 − L 2 for any given √ √ Theorem 3.1, the above problem 3.13 has at 0 < θ < 3 π/1284 26 2. Therefore, By √ √ least one solution for 0 < θ < 3 π/1284 26 2. References 1 A. A. Kilbas, H. M. Srivastava, and J. J. Trujillo, Theory and Applications of Fractional Differential Equations, vol. 204 of North-Holland Mathematics Studies, Elsevier, Amsterdam, The Netherlands, 2006. 2 “The fractional calculus and its applications,” in Lecture Notes in Mathematics, B. 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