Volume 2025, Issue 1 9932318
Research Article
Open Access

A Higher Order Nonresonant p-Laplacian Boundary Value Problem on an Unbounded Domain

S. A. Iyase

S. A. Iyase

Department of Mathematics , Covenant University , Ota , Ogun State , Nigeria , covenantuniversity.edu.ng

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O. F. Imaga

Corresponding Author

O. F. Imaga

Department of Mathematics , Covenant University , Ota , Ogun State , Nigeria , covenantuniversity.edu.ng

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First published: 13 March 2025
Academic Editor: Douglas R. Anderson

Abstract

In this article, we prove the existence of at least one solution to the nonresonant higher-order p-Laplacian boundary value problem of the form:

with the nonresonant condition . We employ the Leray–Schauder continuation principle and some apriori estimates to obtain our result.

MSC2010 Classification: 34B10, 34B15

1. Introduction

The purpose of this study is to derive existence result for the p-Laplacian boundary value problem:
()
()
where φp(s) = |s|p−2s, p > 1, satisfies Caratheodory’s condition with respect to L1[0, ∞), 0 ≤ ηj, , q > 1, , j = 1, 2, …, n, σ(r) ∈ C[0, ∞), σ(r) > 0 and . This problem is nonresonant if the associated problem:
()
subjected to Equation (2) has only the trivial solution.
In [1], Gupta studied the nonresonant p-Laplacian boundary value problem of the form:
for which existence result was obtained under nonresonant condition using topological degree theory.

In recent years, boundary value problems with p-Laplacian have received a lot of attention in the literature. Existence results have been obtained by utilising degree theory, fixed point theorems, upper and lower solution techniques and monotone iteration method. For some results in these directions, see [111] and the references therein. Boundary value problems with a p-Laplacian occur in diverse areas such as in non-linear elasticity, blood flow models, non-Newtonian mechanics, glaciology, et cetera. To the best of our knowledge, higher-order p-Laplacian boundary value problems at nonresonance on an unbounded domain have not received much attention in the literature. This paper, therefore, attempts to bridge this gap.

This paper is organised as follows: in Section 2, we provide background definitions and some key theorems and lemmas including the apriori estimates that will be used in the subsequent sections. Section 3 is devoted to proving the main result, and in Section 4, we provide an example to validate our result.

2. Preliminaries

We recall some theorems and definitions. Let X and Y be Banach spaces with the norms ‖⋅‖X and ‖⋅‖Y, respectively. Let AC[0, ∞) be the space of absolutely continuous function on [0, ∞) and let:
()
with the norm:
()

Then, X is a Banach space.

Let Y = L1[0, ∞) with the norm:
()
We define the mapping N : XY by:
()

Definition 1. The map is L1[0, ∞) Caratheodory if the following conditions are fulfilled:

  • (i)

    for each , g(r, u) is Lebesgue measurable;

  • (ii)

    for a.e. r ∈ [0, ∞), g(r, u) is continuous on ;

  • (iii)

    for each b > 0, there exists αbL1[0, ∞) such that for a.e. r ∈ [0, ∞) and every u such that ‖u‖ < b, we have:

    ()

We now state the Leray–Schauder continuation principle.

Theorem 1. [12] Let L : XX be a compact mapping and X a Banach space. Suppose that there exists b > 0 such that if u = λLu for λ ∈ [0, 1] and ‖u‖ ≤ b, then, L has a fixed point in X.

In what follows, we shall apply the above theorem which has been used by researchers to obtain existence results. However, since we are dealing with an unbounded domain [0, ∞), the compactness principle on the bounded interval [0, 1] is not applicable here. We shall, therefore, apply the following result:

Theorem 2. [13] Let X be the space of all bounded continuous vector valued functions on [0, ∞) and WX. Then, W is relatively compact on X if the following conditions hold:

  • (i)

    W is bounded in X;

  • (ii)

    the functions from W are equicontinuous on any compact interval of [0, ∞);

  • (iii)

    the functions from W are equiconvergent at infinity.

Lemma 1. The boundary value problem (2) and (3) has only the trivial solution if and only if .

Proof. From Equation (3), we obtain:

or
()
So that,
()
and hence,
()
where .

For non-resonance, we must have B = C = 0. From u(0) = 0, we obtain C = 0, while from Equation (3) we derive:

which implies,
that is,
()
From Equation (2), we have:
()
Therefore, from Equations (12) and (13), we obtain:
or
Since , we have B = 0.

In what follows, we shall assume the following constants:
()
()

Lemma 2. Let kY, then the unique solution of the equation:

()
subjected to Equation (2) is given by:
()

Proof. From Equation (16), we obtain:

so that,
()
From Equation (16), we have:
so that,
Thus,
()
Therefore, from Equation (18), we derive:

Lemma 3. Let kY, then the solution Equation (17) satisfies:

()
()
and thus,
()
where A1 and A2 are as in Equations (14) and (15).

Proof. From Equation (17), we obtain:

Also,
Hence,
()
where A = max(A1, A2).

Let T : YX be defined by:
then, T is well defined for all kY and is the unique solution of:
subjected to Equation (2).
Let L = TN : XX be defined by:
then, L is well defined. We prove the compactness of L by applying Theorem 2.

Lemma 4. The mapping L : XX is compact.

Proof. Let WX be bounded with:

()
Since is L1[0, ∞) Caratheodory, there exists αbY such that |Nu(r)| ≤ αb(r) for b ∈ [0, ∞) and uW. Therefore, for uW and 0 ≤ in − 2:
()
For i = n − 1,
()
Equations (24) and (25) implies that:
()
This shows that L(W) is bounded in X. Next, we prove that L(W) is equicontinuous. Let r1,  r2 ∈ [0, D], D ∈ (0, ∞) with r1 < r2 and uW. Then, for 0 ≤ in − 2, we have:
For i = n − 1, we have:
and hence,

Therefore, L(W) is equicontinuous on every compact subset of [0, ∞). Next, we show that LW is equiconvergent at infinity. For uW and for 0 ≤ in − 2, we have:
For i = n − 1, we derive:

This implies that L(W) is equiconvergent at infinity. Thus, all the conditions of Theorem 2 are satisfied, and hence, L(W) is, therefore, relatively compact. The continuity of L(W) follows from the Lebesgue dominated convergence theorem.

3. Main Result

Theorem 3. Let be a L1[0, ∞) Caratheodory function. Suppose there exist positive functions bi,  a : [0, ∞) → [0, ∞) such that:

()
with,
()
where A is defined in Equation (27). Then, the boundary value problem (1) and (2) has at least one solution for every aL1[0, ∞).

Proof. Let u be any solution of the equation:

subjected to Equation (2), λ ∈ [0, 1]. Then,
which yields,
or
Then, from Equation (27), we derive:
()
This implies that the set of solutions of Equations (1) and (2) are a priori bounded by a constant independent of λ and of solutions. This proves the theorem.

4. Example

We consider the boundary value problem:
()
()
where σ(r) = er, p = 3, and aY, a > 0.

All the conditions of Theorem 3 are verified, and thus, Equations (31) and (32) has at least one solution for every aY.

Disclosure

An earlier version of this work has been presented as a conference paper titled ‘A third-order p-Laplacian boundary value problem on an unbounded domain’.

Conflicts of Interest

The authors declare no conflicts of interest.

Author Contributions

The first author conceived the idea and developed the theory. The second author did the literature review. The results where discussed by all authors who also contributed to the final manuscript.

Funding

The authors received no specific funding for this research.

Acknowledgments

The authors would like to thank the Covenant University for their support during the study period. The authors received no specific funding for this work.

    Data Availability Statement

    Data sharing is not applicable to this article as no datasets were generated or analysed during the current study.

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