- Ting-Ting Sun
^{1}, - Lin-Lin Wang
^{1}Email author and - Yong-Hong Fan
^{1}

**2010**:809497

**DOI: **10.1155/2010/809497

© Ting-Ting Sun et al. 2010

**Received: **6 October 2009

**Accepted: **19 January 2010

**Published: **28 January 2010

## Abstract

The nonlocal boundary value problem, with -Laplacian of the form , has been considered. Two existence criteria of at least one and three positive solutions are presented. The first one is based on the Four functionals fixed point theorem in the work of R. Avery et al. (2008), and the second one is based on the Five functionals fixed point theorem. Meanwhile an example is worked out to illustrate the main result.

## 1. Introduction

Due to the unification of the theory of differential and difference equations, there have been many investigations working on the existence of positive solutions to boundary value problems for dynamic equations on time scales. Also there is much attention paid to the study of multipoint boundary value problem with -Laplacian; see [1–10].

For convenience, throughout this paper we denote as the -Laplacian operator, that is, , . , where .

In [11], the author discussed the positive solutions of a -point boundary value problem for a second-order dynamic equation on a time scale

where , , and with . And he got the existence of at least two positive solutions of the above problem by means of a fixed point theorem in a cone.

Zhao and Ge [9] considered the following multi-point boundary value problem with one-dimensional -Laplacian:

where , , , , , . By using a fixed point theorem in a cone, they obtained the existence of at least one, two, or three positive solutions under some sufficient conditions.

Motivated by the above results, in this paper, we investigate the nonlocal boundary value problem with -Laplacian

- (H1)
- (H2)
- (H3)

By using the Four functionals fixed point theorem and Five functionals fixed point theorem, we obtain the existence criteria of at least one positive solution and three positive solutions for the BVP (1.3). As an application, an example is worked out finally. The remainder of this paper is organized as follows. Section 2 is devoted to some preliminary discussions. We give and prove our main results in Section 3.

## 2. Preliminaries

The basic definitions and notations on time scales can be found in [12, 13]. In the following, we will provide some background materials on the theory of cones in Banach spaces. For more details, please refer to [14, 15].

Definition 2.1.

- (1)
- (2)

Every cone induces a partial ordering " " on defined by if and only if

Definition 2.2.

A map is said to be a nonnegative continuous concave functional on a cone of a real Banach space if is continuous and for all and . Similarly, we say that the map is a nonnegative continuous convex functional on a cone of a real Banach space if is continuous and for all and .

Let and be nonnegative continuous concave functionals on , and let and be nonnegative continuous convex functionals on ; then for positive numbers and , define the sets

The following lemma can be found in [16].

Lemma 2.3 (four functionals fixed point theorem).

We are now in a position to present the Five functionals fixed point theorem (see [17]). Let be nonnegative continuous convex functionals on and nonnegative continuous concave functionals on . For nonnegative numbers and define the following convex sets:

Lemma 2.4 (five functionals fixed point theorem).

- (i)
- (ii)
- (iii)
- (iv)

Consider the Banach space equipped with the norm . Suppose , with . For the sake of convenience, we take the notations

Define a cone

Lemma 2.5.

Proof.

From the definition of , it is clear that

is continuous, and is the maximum value of on .

## 3. Main Results and an Example

Theorem 3.1.

Assume that (H1), (H2), and (H3) hold, if there exist constants , , , with , , and suppose that satisfies the following conditions:

Define maps

and let , and be defined by (2.1).

In order to complete the proof of Theorem 3.1, we first need to prove the following lemma.

Lemma 3.2.

is bounded and is completely continuous.

Proof.

For all , , which means that is a bounded set.

According to Lemma 2.5, it is clear that .

In view of the continuity of , there exists a constant such that , for all , . Consider

which means that is uniformly bounded.

In addition, for all , we have

Applying the Arzelà-Ascoli theorem on time scales [18], one can show that is relatively compact.

Now we prove that is continuous. Let be a sequence in which converges to uniformly on . Because is relatively compact, the sequence admits a subsequence converging to uniformly on . In addition,

From the definition of , we know that on . This shows that each subsequence of uniformly converges to . Therefore the sequence uniformly converges to . This means that is continuous at . So, is continuous on since is arbitrary. Thus, is completely continuous. This completes the proof.

Proof of Theorem 3.1.

So, which means that (i) in Lemma 2.3 is satisfied.

For all with and , we have , and for all with and , we obtain that . Hence, (ii) and (iv) in Lemma 2.3 are fulfilled.

Thus (iii) and (v) in Lemma 2.3 hold true. So, by Lemma 2.3, the BVP (1.3) has a fixed point in . This completes the proof.

Theorem 3.3.

Assume that (H1), (H2), and (H3) hold. If there exist constants , with , , , , , further suppose that satisfies the following conditions:

Proof.

Using similar methods as those in Lemma 3.2, we obtain that is completely continuous. Thus, we only need to show that . Let , then

So, , , , which means that and are not empty.

Thus (i) and (ii) in Lemma 2.4 hold.

On the other hand, for with , we have . And for with , we can obtain Thus, (iii) and (iv) in Lemma 2.4 hold.

So, by Lemma 2.4, we obtain that the BVP (1.3) has at least three positive solutions such that

This completes the proof.

Remark 3.4.

Let , , , we can find that the conditions of Theorem 3.1 are contained in Theorem 3.3.

Example 3.5.

and let , , , , . Clearly, we can verify that the conditions in Theorem 3.3 are fulfilled. Thus, by Theorem 3.3, the BVP (3.21) has at least three positive solutions , and such that

Remark 3.6.

If we let , , , , we can also verify that the conditions in Theorem 3.1 are satisfied.

## Declarations

### Acknowledgments

This work is supported by the Natural Science Foundation of Ludong University (24200301, 24070301, 24070302), Program for Innovative Research Team in Ludong University, and a Project of Shandong Province Higher Educational Science and Technology Program.

## Authors’ Affiliations

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