Homoclinic solutions for a class of second order discrete Hamiltonian systems

Consider the second order discrete Hamiltonian systems Δ2u(n-1)-L(n)u(n) + ▽W (n, u(n)) = f(n),where n ∈ Z, u ∈ RN and W : Z × RN → R and f : Z → RN are not necessarily periodic in n. Under some comparatively general assumptions on L, W and f , we establish results on the existence of homoclinic orbits. The obtained results successfully generalize those for the scalar case.     

BIFURCATION SOLUTION BRANCHES AND ITS NUMERICAL ANALYSIS OF A SEMI-LINEAR ELLIPTIC PROBLEM

1　IntroductionConsider the parameter dependent equationu"+ (λ+ s(μ) ) f( u) -μsinx =0　 in ( 0 ,π)u( 0 ) =u(π) =0 ( 1 .1 )whereλ,μ∈R are parameters and f:R→R and S:R→R are smooth odd functions anda) f′( 0 ) =1 ,　　 b) f ( 0 )≠ 0 ,　　 c) s( 0 ) =0 ,　　 d) s′( 0 ) =1 . ( 1 .2 )Let S:u( x)→ u(π-x) ,Γ ={ S,I} ,then ( 1 .1 ) isΓ -equivariant.The equality ( 1 .2 a) isjust a normalization of f at x=0 .Otherwise,one may reseek the parameter x to ensure( 1 .2 a) .To simplify an…     

The existence and multiplicity of solutions of a fractional Schrdinger-Poisson system with critical growth

In this paper, we study the existence and multiplicity of solutions for the following fractional Schr¨odinger-Poisson system:ε~(2s)(-?)~su + V(x)u + ?u = |u|~2_s~*-2 u + f(u) in R~3,ε~(2s)(-?)~s? = u~2 in R~3,(0.1)where 3/4 s 1, 2_s~*:=6/(3-2s)is the fractional critical exponent for 3-dimension, the potential V : R~3→ R is continuous and has global minima, and f is continuous and supercubic but subcritical at infinity. We prove the existence and multiplicity of solutions for System(0.1) via variational methods.     

EXISTENCE OF A COOPERATIVE ELLIPTIC SYSTEM INVOLVING PUCCI OPERATOR

The authors study the existence of solutions for the nonlinear elliptic system -Mλ+,Λ(D2u)=f(u,v) in Ω,-Mλ+,Λ(D2v)=g(u,v) in Ω,u≥0,v≥0 in Ω,u=v=0 on Ω,where Ω is a bounded convex domain in RN,N ≥ 2.It is shown that under some assumptions on f and g,the problem has at least one positive solution(u,v).     

BOUNDEDNESS OF THE HIGHER-DIMENSIONAL QUASILINEAR CHEMOTAXIS SYSTEM WITH GENERALIZED LOGISTIC SOURCE

This article considers the following higher-dimensional quasilinear parabolicparabolic-ODE chemotaxis system with generalized Logistic source and homogeneous Neumann boundary conditions■in a bounded domain??R~n(n≥2) with smooth boundary??, where the diffusion coefficient D(u) and the chemotactic sensitivity function S(u) are supposed to satisfy D(u)≥M1 (u+1)~(-α) and S(u)≤M2(u+1)~β, respectively, where M_1, M_2 0 andα,β∈R. Moreover, the logistic source f (u) is supposed to satisfy f (u)≤a-μu~γ with μ 0,γ≥1, and a≥0. As α+2βγ-1+2γ/n, we show that the solution of the above chemotaxis system with sufficiently smooth nonnegative initial data is uniformly bounded.     

带有非紧条件的拟线性Schrodinger-Poisson系统非平凡解的存在性

本文研究了如下带有非紧条件的拟线性Schrodinger-Poisson系统{-△u+V(x)u+Фu+k/2u△u2=λ|u|^p-2u+f(u),x ∈R^3,-ΔФ=u^2,x∈R^3, 其中κ<0,λ>0,p≥12,f∈C(R,R),V∈C(R3,R).文中首先构造截断函数,利用集中紧性原理和逼近的方法,得到了截断后系统非平凡解的存在性;然后利用Moser迭代技巧,讨论上述系统非平凡解的存在性.     

Multiple Solutions for the Klein-Gordon-Maxwell System with Steep Potential Well

In this paper,we concern the Klein-Gordon-Maxwell system with steep potential well{-△u+(λa(x)+1)u-(2w+φ)φu=f(x,u),in R^3-△φ=-(w+)u^2,in R^3 Without global and local compactness,we can tell the difference of multiple solutions from their norms in Lp(R3).     

一类带导数项的非线性特征值问题正解的存在性

应用 Schauder不动点定理 ,证明了带导数项的非线性特征值问题 :　　 u″+λa( t) f ( u,u′) =0 ,0 0充分小 ,f :[0 ,∞ )× R→ R连续且 f( 0 ,0 ) >0 .     

UPPER SEMICONTINUITY OF ATTRACTORS FORTHE REACTION DIFFUSION EQUATION

1IntroductionInthepresentpaper,weconsiderthefollowingreactiondiffusionequation:at~vAn f(u) A0u g(x)=0,V(x,t)ERxR .(1.1).u(x,0)=u000,VxER,(1.2)andforO=(--n,n)withnEN,otu.~aam. f(,u.) A0u,, g(x)=0,V(x,t)EfixR .(1.3)u.(x,0)=.no.(x),VxeO,(1.4)un(~n,f)=un(n,t)=0,(1.5)whereuandAcarepositivenumbers,g(x)EL'(R),f:R~Risasmoothfunctionwhichsatisfiesf(u)u20,VatER,(1.6)f(0)=0,f,(0)=0,f'(u)2~C,VatER,(1.7)If'(u)I5C(1 fi4lp),p>0,V.uER,(1.8)Inthefollowing,wedenotebyH=L'(R)witlltheusualillnerpro…     

一类四阶抛物型方程的解的渐近行为

本文考虑一维空间中四阶抛物型方程Cauchy问题{ut-(e)2xu+(e)4xu=(e)xf(u), x∈R,t＞0,u(x,0)=u0(x), x∈R,的整体解u=u(x,t)的大时间渐近行为和时间衰减速率,其中f(u)∈C1(R), |f(u)|≤C|u|q, q＞5/2.     

On the Periodic Solution to the Newtonian Equation of Motion

Consider the system of ordinary differential equation u”(t)+grad G(u(t))=p(t),(1)where p:R→R”is continuous and 2π periodic and G:R~π→R has continuous secondorder partial derivatives.The system can be interpreted physically as the Newto-nian equation of motion of a mechanical system subject to conservative internalforces and the periodic external forces.     

一类P-LAPLACIAN边值问题的多个正解

基于 Leggett-Williams在锥上的不动点定理研究两点边值问题(φp( u′( t) ) )′+ a( t) f ( u( t) ) =0　 t∈ ( 0 ,1 )u′( 0 ) =0 ,　αu′( 1 ) + u( 1 ) =0其中 α∈ R,a:( 0 ,1 )→ [0 ,+∞ ) ,f :[0 ,+∞ )→ R,p( z) =| z| p- 2 z,获得了保证正解存在的充分条件     

Existence of Generalized Heteroclinic Solutions of the Coupled Schrdinger System under a Small Perturbation

The following coupled Schrdinger system with a small perturbation uxx + u- u3+ βuv2+ f(, u, ux, v, vx) = 0 in R,vxx- v + v3+ βu2v + g(, u, ux, v, vx) = 0 in R is considered, where β and are small parameters. The whole system has a periodic solution with the aid of a Fourier series expansion technique, and its dominant system has a heteroclinic solution. Then adjusting some appropriate constants and applying the fixed point theorem and the perturbation method yield that this heteroclinic solution deforms to a heteroclinic solution exponentially approaching the obtained periodic solution(called the generalized heteroclinic solution thereafter).     

一阶离散周期问题的多解性

Let T 1 be an integer, T = {0, 1, 2,..., T- 1}. This paper is concerned with the existence of periodic solutions of the discrete first-order periodic boundary value problems△u(t)- a(t)u(t) = λu(t) + f(u(t- τ(t)))- h(t), t ∈ T,u(0) = u(T),where △u(t) = u(t + 1)- u(t), a : T → R and satisfies∏T-1t=0(1 + a(t)) = 1, τ : T → Z t- τ(t) ∈ T for t ∈ T, f : R → R is continuous and satisfies Landesman-Lazer type condition and h : T → R. The proofs of our main results are based on the Rabinowitz's global bifurcation theorem and Leray-Schauder degree.     

奇异半线性椭圆方程的非径向正整体解

研究如下N维奇异半线性椭圆方程△u+f(x,u)=0, x∈RN(N≥3),其中函数f:RN× R+→R+连续,在u=0有奇异性;采用上-下解方法给出该方程具有满足如下性质的有界正整体解u的条件: u∈C2+θloc(RN)使得lim |x|→∞ u(x)=0且u(x)≥εmin{1,|x|2-N},其中ε＞0是常数;并证明:若条件添加"f关于u单调不增"的限制,则这种解是唯一的.     

THE EXISTENCE OF NONTRIVIAL SOLUTIONS TO A SEMILINEAR ELLIPTIC SYSTEM ON RN WITHOUT THE AMBROSETTI-RABINOWITZ CONDITION

In this paper, we prove the existence of at least one positive solution pair (u, v) ∈ H 1 (R N ) × H 1 (R N ) to the following semilinear elliptic system{-u + u = f(x, v), x ∈RN ,-v + v = g(x,u), x ∈ R N ,(0.1) by using a linking theorem and the concentration-compactness principle. The main con-ditions we imposed on the nonnegative functions f, g ∈ C 0 (R N × R 1 ) are that, f (x, t) and g(x, t) are superlinear at t = 0 as well as at t = +∞, that f and g are subcritical in t and satisfy a kind of monotonic conditions. We mention that we do not assume that f or g satisfies the Ambrosetti-Rabinowitz condition as usual. Our main result can be viewed as an extension to a recent result of Miyagaki and Souto [J. Diff. Equ. 245(2008), 3628-3638] concerning the existence of a positive solution to the semilinear elliptic boundary value problem{-u + u = f(x, u), x ∈Ω,u ∈H10(Ω)where ΩRN is bounded and a result of Li and Yang [G. Li and J. Yang: Communications in P.D.E. Vol. 29(2004) Nos.5 6.pp.925–954, 2004] concerning (0.1) when f and g are asymptotically linear.     

NUMERICALLY SOLVING PERIODICALLY PERTURBED CONSERVATIVE SYSTEMS BY PARAMETER EMBEDDING METHODS

1　IntroductionConsider the system of differential equationsTu≡ u"+ F( t,u) =0 ( 1 )where F:R×Rn→Rnis a continuos function of2 π-period with respect to tand F( t,· )∈ C1( Rn,Rn) has a symmetric derivative for all t∈R and allξ∈Rn.When the system is of the formu"+ grad G( u) =e( t) ( 2 )where G∈C2 ( Rn,R) ,e:R→Rncontinuousand2 π-periodic.Equation( 2 ) can be interpreted asthe Newtonian equation ofmotion ofa mechanicalsystem subjectto conservative internal forcesand periodic e…     

EXISTENCE AND UNIQUENESS OF STRONG PERIODIC SOLUTION OF THE EVOLUTION SYSTEM DESCRIBING GEOPHYSICAL FLOW—PART I： IN BOUNDED DOMAINS

61. IntroductionDiscovered by R. HideI3], the following evolution system has been used to describe thegeophysical flow:where u = u(xl,',XN,t) = (ul,',UN) and B = B(xl,',XN,t) = (BI,',BN) arethe velocity vectors Of Eulerian flow and magnetic fields respectively. p(x, t) and q(x, t) arepressures. j(x, t) and g(x,t) are volUme forces. p and u are the constants of density andviscosity of the flow respeCtively, p is the constant of magnetic permeability and A = f withelectrical resis…     

共振情形下周期边值问题正解的全局分歧

考虑共振情形下二阶常微分方程周期边值问题{u'=f(t,u), t∈(0,2π), u(0)=u(2π), u'(0)=u'(2π)正解的全局分歧,其中f:[0,2π]×R→R(R=(-∞,+∞))为连续函数.运用Dancer全局分歧定理获得了上述问题至少存在一个正解的若干充分条件,这些充分条件中所涉及的值是最优的.     

带参数的一阶泛函差分方程的定号周期解

In this paper,the authors obtain the existence of one-signed periodic solutions of the first-order functional difference equation ?u(n) = a(n)u(n)-λb(n)f(u(n-τ(n))),n ∈ Z by using global bifurcation techniques,where a,b:Z → [0,∞) are T-periodic functions with ∑T n=1 a(n) 0,∑T n=1 b(n) 0;τ:Z → Z is T-periodic function,λ 0 is a parameter;f ∈ C(R,R) and there exist two constants s_2 0 s_1 such that f(s_2) = f(0) = f(s_1) = 0,f(s) 0 for s ∈(0,s_1) ∪(s_1,∞),and f(s) 0 for s ∈(-∞,s_2) ∪(s_2,0).