Volume 2012, Article ID 831960,12pages doi:10.1155/2012/831960
Research Article
On the Nonhomogeneous Fourth-Order
p-Laplacian Generalized Sturm-Liouville Nonlocal Boundary Value Problems
Jian Liu
1and Zengqin Zhao
21School of Mathematics and Quantitative Economics, Shandong University of Finance and Economics, Shandong, Jinan 250014, China
2School of Mathematical Sciences, Qufu Normal University, Shandong, Qufu 273165, China
Correspondence should be addressed to Jian Liu,[email protected] Received 3 August 2012; Accepted 12 September 2012
Academic Editor: Yanbin Sang
Copyrightq2012 J. Liu and Z. Zhao. 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 the nonlinear nonhomogeneous n-point generalized Sturm-Liouville fourth-order p- Laplacian boundary value problem by using Leray-Schauder nonlinear alternative and Leggett- Williams fixed-point theorem.
1. Introduction
In this paper, we prove the existence of one and multiple positive solutions of the following differential equations:
φp
ut
−k2φp ut
gtft, ut, t∈0,1, u0 φqa, u1 φqb,
αu0−βu0 n−2
i1
aiuξi,
γu1 δu1 n−2
i1
biuξi,
1.1
whereφpisp-Laplacian operator, that is,φpu |u|p−2u,p >1,φp−1φq, 1/p1/q1m,k /0, α, β, γ, δ0,ξi∈0,1,a, b, ai, bi ∈0,∞ i1,2, . . . , n−2,f ∈C0,1×0,∞,0,∞, ft,0/≡0,gt∈C0,1,0,∞.
Recently, much attention has been paid to the existence of positive solutions for nonlocal nonlinear boundary value problems BVPs for short, see 1–4 and references therein. Such problems have potential applications in physics, biology, chemistry, and so forth. For example, a second-order three-point is used as a model for the membrane response of a spherical cap in nonlinear diffusion generated by nonlinear sources and in chemical reactor theory.
At the same time, the boundary value problems withp-Laplacian operator have been discussed extensively, for example, see1–3,5–7.
In1, Feng et al. researched the boundary value problem φp
u
t qtft, ut, 0t1, u0 m
i1
aiuξi, u1 m
i1
biuξi; 1.2
they obtained at least one or two positive solutions under some assumptions imposed on the nonlinearity offby applying Krasnoselskii fixed-point theorem.
Zhou and Ma studied the existence and iteration of positive solutions for the following third-order generalized right-focal boundary value problem withp-Laplacian operator in3:
φp u
t qtft, ut, 0t1, u0 m
i1
αiuξi, u η
0, u1 n
i1
βiuθi; 1.3
they established a corresponding iterative scheme for1.4by employing the monotone itera- tive technique.
We would also like to mention the work of Zhang and Liu in7, in which they con- sidered the existence of positive solutions for
φp
ut
ft, ut, 0< t <1, u0 n−2
i1
aiuξi, u1 0, u0 n−2
i1
biuξi, u1 0,
1.4
by virtue of monotone iterative techniques, and they established a necessary and sufficient condition of positive solutions for their problem.
However, to the best of our knowledge, there are not many results concerning about the existence and multiple solutions of fourth-orderp-Laplacian generalized Sturm-Liouville n-point boundary value problems. In this paper, motivated by the study of4,8, we commit- ted to consider the fourth-orderp-Laplacian generalized Sturm-Liouville nonlocal boundary value problem without assuming any monotonicity condition on the nonlinearityf.
The rest of the paper is arranged as follows. We state some definitions and several preliminary results inSection 2that we will use in the sequel. Then inSection 3we present
the existence of one positive solution of BVP1.1by Leray-Schauder nonlinear alternative.
InSection 4we get three solutions by Leggett-Williams fixed-point theorem.
2. Preliminaries and Some Lemmas
The basic space used in this paper isEC0,1. It is well known thatEis a real Banach space with the normumaxt∈0,1|ut|.
Denote
ϕt βαt, ψt γδ−γt, t∈0,1, ραγβγαδ,
Δ
−n−2
i1aiϕξi ρ−n−2
i1aiψξi ρ−n−2
i1biϕξi −n−2
i1biψξi .
2.1
Definition 2.1. A functionuis said to be a solution of the boundary value problem1.1if u∈C20,1satisfies1.1andφpu∈C20,1. In addition,uis said to be a positive solution ifut>0 fort∈0,1, anduis a solution of BVP1.1.
Throughout the paper, we assume the following condition is satisfied:
H0ρ > 0, ρ−n−2
i1 aiψξi > 0, ρ−n−2
i1 biϕξi > 0,Δ < 0, ft, ut k2ab/
mint∈0,1gt.
Letyt −φput, then BVP1.1is divided into the following two parts:
−yk2ygtft, ut, t∈0,1,
y0 a, y1 b, 2.2
uφq y
0, t∈0,1, αu0−βu0 n−2
i1
aiuξi, γu1 δu1 n−2
i1
biuξi. 2.3
It is not difficult that we can transform2.2into the following differential equations:
−yk2ygtft, ut−k2a1−t−k2bt, t∈0,1,
y0 0, y1 0. 2.4
By routine calculations we can get the following three Lemmas.
Lemma 2.2. The BVP2.4has a unique solution
yt 1
0
G1t, s
gsfs, us−k2a1−s−k2bs ds, 2.5
where
G1t, s 1 ρ
⎧⎪
⎪⎨
⎪⎪
⎩
sinhks·sinhk1−t
ksinhk , 0st1, sinhkt·sinhk1−s
ksinhk 0ts1.
2.6
Lemma 2.3. The BVP2.3has a unique solution
ut 1
0
G2t, sφq
ys
dsAϕt Bψt, 2.7
where
G2t, s 1 ρ
ψtϕs, 0st1, ψsϕt, 0ts1,
A 1 Δ
n−2
i1
ai 1
0
G2ξi, sφq
ys
ds ρ−n−2
i1
aiψξi
n−2
i1
bi
1
0
G2ξi, sφq
ys
ds −n−2
i1
aiψξi ,
B 1 Δ
−n−2
i1
aiϕξi n−2
i1
ai 1
0
G2ξi, sφq
ys ds
ρ−n−2
i1
aiϕξi n−2
i1
bi 1
0
G2ξi, sφq
ys ds
.
2.8
The proof ofLemma 2.3is similar to that of Lemma 5.5.1 in8, so we omit it here.
From Lemmas2.2and2.3we can get thatutis a solution of BVP1.1if and only if
ut 1
0
G2t, sφq
1
0
G1s, τ
gτfτ, uτ−k2a1−τ−k2bτ ds A
φq
y
ϕt B φq
y ψt,
2.9
where A
φq y
1 Δ
n−2 i1
ai
1
0
G2ξi, sφq
1
0
G1s, τ
gτfτ, uτ−k2a1−τ−k2bτ dτ
ds ρ−n−2
i1
aiψξi
n−2
i1
bi
1
0
G2ξi, sφq
1
0
G1s, τ
gτfτ, uτ−k2a1−τ−k2bτ dτ
ds −n−2
i1
aiψξi ,
B φq
y
1 Δ
−n−2
i1
aiϕξi n−2
i1
ai 1
0
G2ξi, sφq
1
0
G1s, τ
gτfτ, uτ−k2a1−τ−k2bτ dτ
ds
ρ−n−2
i1
aiϕξi n−2
i1
bi 1
0
G2ξi, sφq
1
0
G1s, τ
gτfτ, uτ−k2a1−τ−k2bτ dτ
ds .
2.10 Lemma 2.4. Consider,
Git, sGis, s, t, s∈0,1, i1,2, G1t, sΛ0G1s, s, t∈,1−, s∈0,1,
G2t, sΛG2s, s, t∈,1−, s∈0,1,
2.11
where
Λ0 sinhk sinhk , ∈
0,1
2
, Λ min
ϕ
ϕ1,ψ1− ψ0
, ∈
0,1
2
.
2.12
Denote
Λ1maxϕ,ψ, Λ2min
t∈,1−min ϕt, min
t∈,1−ψt
, λmin
Λ,Λ2
Λ1
. 2.13
Lemma 2.5. Let K
u|u∈C0,1, ut0,∀t∈0,1, min
t∈,1−utλu
,
Tut 1
0
G2t, sφq
1
0
G1s, τ
gτfτ, uτ−k2a1−τ−k2bτ ds A
φq y
ϕt B φq
y ψt,
2.14
then
TK⊆K. 2.15
Proof. Firstly, we prove thatTut0. Forf ∈C0,1×0,∞,0,∞,gt∈C0,1,0,∞, then we can getφqy φq1
0G1s, τgτfτ, uτ−k2a1−τ−k2bτdτ > 0, for all u∈ K. Furthermore, conditionH0leads toAφqy 0, andBφqy0, thus, we get Tut0.
Secondly, fort∈,1−, we can get
t∈,1−min Tut
min
t∈,1−
1
0
G2t, sφq
1
0
G1s, τ
gτfτ, uτ−k2a1−τ−k2bτ dτ
ds
A φq
y
ϕt B φq
y ψt
Λ
1
0
G2s, sφq
1
0
G1s, τ
gτfτ, uτ−k2a1−τ−k2bτ dτ
ds
A φq
y
ϕt B φq
y ψt
Λ
1
0
G2s, sφq
1
0
G1s, τ
gτfτ, uτ−k2a1−τ−k2bτ dτ
ds
Λ2
Λ1Λ1
A φq
y B
φq
y
λ
1
0
G2s, sφq
1
0
G1s, τ
gτfτ, uτ−k2a1−τ−k2bτ dτ
ds
Λ1
A φq
y B
φq
y
λTu.
2.16
Thus we can get that mint∈,1−TutλTu, which meansTK⊆K.
We present here several definitions.
Given a coneKin a real Banach spaceE, a mapαis said to be a nonnegative continuous concaveresp., convexfunctional onKprovided thatα:K → 0,∞is continuous and
α
tx 1−ty
tαx 1−tα y
, resp., α
tx 1−ty
tαx 1−tα y
,
2.17
for all,x, y∈Kandt∈0,1.
Let 0< a < bbe given, and letαbe a nonnegative continuous concave functional on K. Define the convex setsPrandPα, a, bby
Pr {x∈K| x< r}, Pα, a, b {x∈K|aαx,xb}. 2.18
For the convenience of the reader, we present here the Leggett-Williams fixed-point theorem and the Leray-Schauder nonlinear alternative theorem.
Lemma 2.6see9, Leggett-Williams fixed-point theorem. LetA :Pc → Pcbe a completely continuous operator, and letαbe a nonnegative continuous concave functional onKsuch thatαx x for allx∈Pc. Suppose there exist 0< a < b < dcsuch that
A1{x∈Pα, b, d:αx> b}/∅, andαAx> bforx∈Pα, b, d;
A2Ax< aforxa;
A3αAx> bforx∈Pα, b, cwithAx> d.
ThenAhas at least three fixed pointsx1,x2, andx3and such thatx1< a,b < αx2andx3> a, withαx3< b.
Now we cite the Leray-Schauder nonlinear alternative.
Lemma 2.7see10. LetFbe a Banach space andΩa bounded open subset ofF, 0∈Ω.T :Ω → Fbe a completely continuous operator. Then, either there existsx∈∂Ω,λ >1 such thatTx λx, or there exists a fixed pointx∗∈Ω.
3. Results of One Nontrivial Solution
In this section, we study the existence of one nontrivial solution of BVP 1.1 by Leray- Schauder nonlinear alternative.
Denote
H1φq
1
0
G1τ, τgτpτdτ
,
H2φq
1
0
G1τ, τgτrτdτ
,
A 1 Δ
n−2
i1
ai ρ−n−2
i1
aiψξi n−2
i1
bi −n−2
i1
aiψξi ,
B 1 Δ
−n−2
i1
aiϕξi n−2
i1
ai
ρ−n−2
i1
aiϕξi n−2
i1
bi ,
NM·2q−1
1AΛ 1BΛ 1
, l NH2
1−NH1, Ω {u∈C0,1,u< l}.
3.1
Theorem 3.1. AssumeNH1 <1,ft,0/≡0, and there exist nonnegative functionsp, r ∈L10,1 such that|ft, u|pt|u|p−1rt, a.e.t, u∈0,1×0,∞, then BVP1.1has a nontrivial solutionu∗∈Ω.
Proof. If there exist two nonnegative functionsp, r ∈L10,1such that|ft, u|pt|u|p−1 rt, a.e.t, u∈0,1×0,∞, we can get that
φq
1
0
G1s, τ
gτfτ, uτ−k2a1−τ−k2bτ dτ
φq 1
0
G1s, τgτfτ, uτdτ
φq
1 0
G1τ, τgτ
pτ|u|p−1rτ dτ
2q−1
uφq
1
0
G1τ, τgτpτdτφq 1
0
G1τ, τaτrτ
dτ
2q−1uH1H2,
3.2
thus, we get 1
0
G2ξi, sφq
1
0
G1s, τ
gτfτ, uτ−k2a1−τ−k2bτ dτ
ds
1
0
G2ξi, sφq
1
0
G1s, τgτfτ, uτdτ
ds
M·2q−1uH1H2.
3.3
In the same way, we obtain
A φq
y
M·2q−1uH1H2A, B
φq y
M·2q−1uH1H2B.
3.4
Thus we have Tu max
0t1|Tut|
max
0t1
1
0
G2t, sφq
1
0
G1s, τ
gτfτ, uτ−k2a1−τ−k2bτ ds
A φq
y
ϕt B φq
y ψt
max
0t1
1
0
G2t, sφq
1 0
G1s, τgτfτ, uτdτ
ds
A φq
y
ϕt B φq
y ψt
M·2q−1uH1H2 M·2q−1uH1H2
AΛ 1BΛ 1
M·2q−1uH1H2
1AΛ 1BΛ 1
NuH1H2.
3.5
Suppose that there existsμ >1 such that
Tuμu, u∈∂Ω. 3.6
Therefore,
μlμuTul
NH1NH2
l
, 3.7
which leads toμ NH1NH2/l 1, and this contradicts μ > 1, then by Lemma 2.7,T has a fixed pointu∗∈Ω; sinceft,0/≡0, the BVP1.1has a nontrivial solutionu∗∈Ω. This completes the proof ofTheorem 3.1.
4. Results of Multiple Positive Solutions
In the following parts, we will study the existence of multiple positive solutions of BVP1.1 by using Leggett-Williams fixed-point theorem.
Denote
Pc{u∈K| u< c}. 4.1
Define the nonnegative continuous concave functional onKby
αu min
t1−ut. 4.2
It is obvious that for eachu∈K, αuu.
LetM max0t11
0G2t, sds,m 1−
G2s, sds,h φq1−
k2abG1τ, τdτ, andA, B, Λ,Λ0,Λ1be defined in Sections2and3.
We list the following three hypotheses:
H1ft, u< φpc/M1 Λ1A Λ1B/ 1
0G1τ, τgτdτ, for allt∈0,1, 0uc;
H2ft, u< φpa/M1 Λ1A Λ1B/ 1
0G1τ, τgτdτ, for allt∈0,1, 0ua;
H3ft, u> φp2q−1b/mΛ1Λ1AΛ 1B h/Λ0
1−
G1τ, τgτdτ, for allt∈0,1, bub/λ.
Theorem 4.1. AssumeH1–H3hold, then BVP1.1has at least three positive solutionsu1, u2, andu3, such thatu1< a,b <min,1−u2t, andu3> a, with min,1−u3t< b.
Proof. Firstly, we prove thatT :Pc → Pc. The operatorTis completely continuous.
From conditionH1, we can get 1
0
G2ξi, sφq
1
0
G1s, τ
gτfτ, uτ−k2a1−τ−k2bτ dτ
ds
Mφq
1
0
G1τ, τgτfτ, uτdτ
c
1 Λ1A Λ1B.
4.3
Hence, Tu max
0t1|Tut|
max
0t1
1
0
G2t, sφq
1
0
G1s, τ
gτfτ, uτ−k2a1−τ−k2bτ dτ
ds
A φq
y
ϕt B φq
y ψt
max
0t1
1
0
G2t, sφq
1
0
G1s, τ
gτfτ, uτdτ ds A
φq
y
ϕt B φq
y ψt
c
1 Λ1A Λ1B c
1 Λ1A Λ1BΛ1A c
1 Λ1A Λ1BΛ1Bc.
4.4
Thus we getTuc; therefore,T :Pc → Pc. The operatorTis completely continuous by an application of Ascoli-Arzela theorem.
In the same way, conditionH2implies that conditionA2ofLemma 2.6is satisfied.
In the following, we show that conditionA1ofLemma 2.6is satisfied.
Let
u0t b
λ, t∈0,1, 4.5
then
u0∈P
α, b,b λ
, αu0
b
λ > b, 4.6
thus,{u∈Pα, b, b/λ|αu> b}/∅.
Ifu∈Pα, b, b/λ, thenbusb/λ,s∈,1−. By conditionH3, we obtain
1
0
G2ξi, sφq
1
0
G1s, τ gτf
τ, uτ−k2a1−τ−k2bτ dτ
ds
Λ
1−
G2s, s 1
2q−1φq 1−
G1s, τgτfτ, uτ dτ ds
−φq
1−
G1s, τ
k2a1−τ k2bτ dτ ds
Λ
1−
G2s, s 1
2q−1φq
1−
G1s, τgτfτ, uτ dτ ds
−φq
1−
G1τ, τ
k2a1−τ k2bτ dτ ds
Λ
1−
G2s, s 1
2q−1φq
1−
G1s, τgτfτ, uτ dτ
−φq
1−
G1τ, τ
k2ak2b dτ ds
b
1 Λ1A Λ1B.
4.7
Thus we get
αTut min
t∈,1−Tut
min
t∈,1−
1−
G2s, sφq
1
0
G1s, τ gτf
τ, uτ−k2a1−τ−k2bτ dτ
ds A
φq
y
ϕt B φq
y ψt
b
1 Λ2A Λ2B b
1 Λ2A Λ2BΛ2A b
1 Λ2A Λ2BΛ2Bb.
4.8 Therefore, conditionA1ofLemma 2.6is satisfied.
Finally, we show that conditionA3ofLemma 2.6is satisfied.
Ifu∈Pα, b, c, andTu> b/λ, thenαTut mint1−TutλTu> b.
Therefore, condition A3 of Lemma 2.6is also satisfied. By Lemma 2.6, there exist three positive solutionsu1,u2, andu3such thatu1< a, b <mint∈,1−u2t, andu3> a, with mint∈,1−u3t< b. Thus we completed the proof.
Acknowledgments
The first author is supported by the Natural Science Foundation of Shandong Province of ChinaZR2012AQ024and the University Science and Technology Foundation of Shandong Provincial Education Department J10LA62. The second author is supported by the National Natural Science Foundation of China10871116, the Natural Science Foundation of Shandong Province of ChinaZR2010AM005, and the Doctoral Program Foundation of Education Ministry of China200804460001.
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