四阶边值问题正解的存在性与多解性

本文讨论了非线性四阶边值问题u^(4)(t)=φ（t）f(u(t),u“(t),t∈(0,1),u(0)=u(1)=u“(0) =u“(1)=0正确的存在性，其中φ（t)∈C([0,1],[0,∞)),f(u,v)∈C（[0,∞],[0,∞))。利用锥压缩与锥拉伸不动点定理，给出了该问题正解存在与多个正解存在的充分条件。     

二阶Nuemann边值问题两个正解的存在性

利用锥上的不动点定理证明了二阶Nuemann边值问题-u〃 Mu=f(t,u),u＇(0)=u＇(1)=0至少有两个正解存在的充分条件。     

奇数阶边值问题正解的存在性与多重性

利用锥拉伸锥压缩不动点定理,证明了在一定条件下,下列非线性奇数阶方程(-1)q+1u(2q+1)(t)=λa(t)f(u(t)),0 t 1,(-1)q+1u(2q+1)(t)=λa(t)f(u(t)),0 t 1,u(0)=u′(τ)=u″(1)=0u(2j+1)(0)=u(2j+1)(1)=0,j=1,2,…,q-1.单个和多个正解的存在性,其中λ>0,12<τ<1,q∈N.得到了λ的区间Λ,对一切λ∈Λ,该问题至少有一个正解,同样也得到了该问题至少有两个正解λ相应的区间.     

非线性三点共轭边值问题正解存在性的特征值准则

本文提出了三点边值问题-v″(t)=b(t)f(v(t)),满足v′(0)=0及v(1)=αv(η)的共轭问题-u″(t)=b(t)f(u(t)),u′(0)=u(1)=0及u′_+(η)-u′_-(η)=αu′(1),得到了相应的Green函数．将其转化为Hammertein型积分方程,借助于其相应线性问题的第一特征值,利用锥上的不动点指数理论,给出了共轭问题单个正解及多个正解存在的特征值准则．     

一类三点边值问题正解的存在性

在与线性问题第一特征值相关的条件下,通过应用不动点指数理论讨论了三点边值问题u″ 9(t)f(u)=0,t∈(0,1),u′(0)=0,u(1)=αu(η)正解的存在性,这里η∈(0,1),α∈R且0<α<1.本文结果推广和改进了文献[1]的主要结论.     

Carathéodory条件下三阶半正边值问题的正解

不要求非线性项f(t,u)连续且下方有界,在f(t,u)满足Carathéodory条件下,讨论了三阶半正边值问题u+λf(t,u)=0,0t1,u(0)=u′(0)=u″(1)=0.当λ>0且充分小时正解的存在性,应用的工具为锥上的不动点.     

一类二阶半正边值问题正解的存在性

利用锥上的不动点定理,在非线性项f,g半正并允许下方可以无界的情形下研究了一类非线性二阶边值问题u″ λf(t,u) μg(t,u)=0,αu(0)-βu′(0)=0,γu(1) δu′(1)=0,在非线性项f与g满足更广的同为超(次)线性和一个为超线性一个为次线性的情形下得到了边值问题的正解,推广,改进和统一了一些已知的结果.     

二阶Nuemann特征值问题的正解

利用锥上的不动点定理证明了二阶Nuemann特征值问题-u″＋Mu=λa（t）f（u（t））m0≤t≤1 u′（0）=u′（1）=0是的正解存在性结果．     

一类非线性$m$-点边值问题的正解

应用锥理论和不动点指数方法,在与相应线性算子的第一特征值相关的条件下,得到了下述非线性二阶常微分方程m-点边值问题{u"(t) a(t)u' b(t)u h(t)f(u(t))=0,0＜t＜1,u'(0)=0,u(1)=m-2∑i=1αiu(ξi).的正解,改进了相关文献中的结论.     

一类奇异边值问题正解的存在性

借助上下解方法和锥拉伸与锥压缩不动点定理研究了二阶非线性奇异边值问题u″ λf(t,u(t))=0,0相似文献   

On an Alternative Parameterization of the Solutions of the Partial Realization Problem

The solutions of the partial realization problem have to satisfy a finite number of interpolation conditions at . The minimal degree of an interpolating deterministic system is called the algebraic degree or McMillan degree of the partial covariance sequence and is easy to compute. The solutions of the partial stochastic realization problem have to satisfy the same interpolation conditions and have to fulfill a positive realness constraint. The minimal degree of a stochastic realization is called the positive degree. In the literature, solutions of the partial realization problem are parameterized by the Kimura–Georgiou parameterization. Solutions of the partial stochastic realization problem are then obtained by checking the positive realness constraint for the interpolating solutions of the corresponding partial realization problem. In this paper, an alternative parameterization is developed for the solutions of the partial realization problems. Both the solutions of the partial and partial stochastic realization problem are analyzed in this parameterization, while the main concerns are the minimality and the uniqueness of the solutions. Based on the structure of the parameterization, a lower bound for the positive degree is derived.     

A PRIORI ESTIMATE AND EXISTENCE OF POSITIVE SOLUTIONS FOR SYSTEM OF SEMILINEAR ELLIPTIC EQUATIONS

1.APrioriBounds##DTherearealotofresultsfortheprioriboundsandtheexistenceofpositivesolutionsofsemilinearellipticequations(see[2],[3]).Weshallinvestigatetheprioriboundsandtheexistenceofpositivesolutionsforsystemofellipticboundaryvalueproblems:Wealwaysassume…     

非线性三阶边值问题反对称变号解的无穷可解性

利用Krasnosel′skii不动点定理及延拓正(负)解的方法,证明了一类非线性三阶三点边值问题,当其非线性项满足某些假设条件时,具有无穷多个反对称变号解.     

Existence of three positive solutions for a class of Riemann-Liouville fractional q-difference equation

In this paper, we confirm the existence of three positive solutions for a class of Riemann-Liouville fractional $q$-difference equation which satisfies the boundary conditions. We gain several sufficient conditions for the existence of three positive solutions of this boundary value problem by applying the Leggett-Williams fixed point theorem.     

A CONDITION OF THE EXISTENCE OF STABLE POSITIVE STEADY-STATE SOLUTIONS FOR A ONE PREDATOR TWO PREY SYSTEM

One predator two prey system is a research topic which has both the theoretical and practical values.This paper provides a natural condition of the existence of stable pcsitive steady-state solutions for the one predator two prey system.Under this conditon we study the existence of the positive steady-state solutions at vicinity of the triple eigenvalue by implicit function theorem,discuss the positive stable solution problem bifureated from the semi-trivial solutions containing two positive components with the help of bifurcation and perturbation methods.     

一般Lidstone边值问题的n个正解的存在性

考察了含所有偶数阶导数的一般Lidstone边值问题的正解和对称正解.通过 选择合适的Banach空间和锥,对该问题建立了n个正解或者对称正解的存在性,其 中n是一个任意的自然数.基本工具是等价范数和锥拉伸与锥压缩型的Krasnosel'skii 不动点定理. 结论的主要条件是局部的.换言之,如果非线性项f在某些有界集上的 "高度"是适当的,则该问题可以具有n个正解.     

二阶三点边值问题正解的存在性

利用不动点指数定理研究了一类二阶非线性常微分方程的三点边值问题正解的存在性问题,得到了至少存在一个或无穷多个正解的几个充分条件.     

Multiple positive solutions to a class of quasi-linear elliptic equations involving critical Sobolev exponent

In this paper, we study the multiplicity results of positive solutions for a quasi-linear problem involving concave-convex nonlinearities and critical Sobolev exponent. With the help of Nehari manifold and a mini-max principle, we prove that problem has at least two or three positive solutions under different conditions.     

Asymptotic behavior of solutions of a periodic diffusion system of plankton allelopathy

This paper is concerned with the existence and asymptotic behavior of periodic solutions for a periodic reaction diffusion system of a planktonic competition model under Dirichlet boundary conditions. The approach to the problem is by the method of upper and lower solutions and the bootstrap argument of Ahmad and Lazer. It is shown under certain conditions that this system has positive or semi-positive periodic solutions. A sufficient condition is obtained to ensure the stability and global attractivity of positive periodic solutions.