超线性非线性Sturm-Liouville边值问题的正解

利用拓扑方法讨论了一类非线性Sturm-Liouville边值问题{-u″=λf(x,u),0≤x≤1,α0u(0)+β0u′(0)=0, α1u(1)+β1u′(1)=0.研究了上述问题的正解的全局结构,在非线性项f(x,u)不满足条件f(x,u)≥0(u≥0)时获得了正解的存在性.     

Banach空间四阶两点问题正解的存在性

讨论了Banach空间E中的四阶边值问题:u~(4)(t)=f t(,u(t)),0≤t≤1,u(0)=u(1)=u″(0)=u″(1)=θ正解的存在性,其中f∶0,[1]×P→P连续,P为E中的正元锥.通过非紧性测度的估计技巧与凝聚映射的不动点指数理论获得了该问题正解的存在性结果.     

二阶奇异微分方程边值问题的正解

利用上下解方法研究二阶奇异微分方程u″+f(t,u)=0在边界条件αu(0)-βu′(0)=0,γu(1)+δu′(1)=0下正解的存在性.允许f(t,u)在t=0,1处奇异.     

超线性非线性Sturm-Liouville边值问题的正解

利用拓扑方法讨论了一类非线性Sturm-Liouville边值问题-u″=λf(x,u),0≤x≤1,α_0u(0)+β_0u′(0)=0,α_1u(1)+β_1u′(1)=0.研究了上述问题的正解的全局结构,在非线性项f(x,u)不满足条件f(x,u)≥0(u≥0)时获得了正解的存在性.     

有序Banach空间中常微分方程正周期解的存在性

讨论了有序Banach空间E中的非线性常微分方程:u′(t)+Mu(t)=f(t,u(t)),(?)t∈R正ω-周期解的存在性,其中f:R×P→P连续,P为E中的正元锥.通过新的非紧性测度的估计技巧与凝聚映射的不动点指数理论获得了该问题正ω-周期解的存在性结果.     

带p-Laplacian算子的四点边值问题拟对称正解的存在性

利用范数形式的锥拉伸与压缩不动点定理,研究了一类p-Laplacian方程四点边值问题(φp(u′(t)))′(t)+λf(t,u(t))=0,t∈(0,1),u(0)-βu′(ξ)=0,u(ξ)-δu′(η)=u(1)+δu′(1+ξ-η),其中φp(s)=sp-2·s,p>1.获得了其拟对称正解的存在性定理.     

奇异二阶Neumann边值问题的正解

考察非线性二阶边值问题-u″(t)+λu(t)=h(t)f(t,u(t))+ζ(t,u(t)),0＜t＜1,u′(0)=u′(1)=0,的正解,其中λ＞0.文中允许ζ(t,u)在t=0,t=1和u=0处奇异.利用锥上的Guo-KraLsnosel'skii不动点定理证明了n个正解的存在性,其中n是任意的正整数.     

一类非线性分数阶微分方程边值问题的正解

讨论以下非线性分数阶边值问题:^cD_(0+)cD_(0+)^αu(t)+λa(t)f(u(t))=0,0cD_(0+)cD_(0+)^α是Caputo导数,λ>0.利用Krasnoselskiis不动点定理,得到其正解存在与不存在的充分条件,最后给出一个例子验证我们的结论.     

关于非线性特征值多点边值问题的四个正解的存在性

利用锥上的不动点定理,考察了一类非线性特征值问题u″(t)+λf(t,u(t))=0,0≤t≤1,u(0)=0,αu(η)=u(1)的多个正解的存在性,给出了四个正解存在的充分条件,这里0<η<1,α>0.     

次线性半正边值问题的正解

本文讨论 Sturm-Liouville边值问题(p(t)u′)′+λf(t,u)=0, r＜t＜R;au(r)-bp(r)u′(r)=0;cu(R)+dp(R)u′(R)=0,正解的存在性,这里允许非线性项取负值．当f在u=+∞处一致次线性增长且无界时，必存在λ^*＞0，对?λ:λ＞λ^*,上述边值问题存在正解．     

RECENT PROGRESS ON SPHERICAL HARMONIC APPROXIMATION MADE BY BNU RESEARCH GROUP ——In memory of Professor Sun Yongsheng

As early as in 1990, Professor Sun Yongsheng, suggested his students at Beijing Normal University to consider research problems on the unit sphere. Under his guidance and encouragement his students started the research on spherical harmonic analysis and approximation. In this paper, we incompletely introduce the main achievements in this area obtained by our group and relative researchers during recent 5 years （2001-2005）. The main topics are： convergence of Cesaro summability, a.e. and strong summability of Fourier-Laplace series; smoothness and K-functionals; Kolmogorov and linear widths.     

Instructions for Authors

<正>Submission Authors must use LaTeX for typewriting,and visit our website www.actamath.com to submit your paper.Our address is Editorial Office of Acta Mathematica Sinica,Academy of Mathematics and Systems Science,Chinese Academy of Sciences,Beijing 100190,P.R.China.     

THE 8~(th) INTERNATIONAL CONGRESS ON INDUSTRIAL AND APPLIED MATHEMATICS

正August 10-14,2015Beijin,China The International Congress on Industrial and Applied Mathematics(ICIAM)is the premier international congress in the field of applied mathematics held every four years under the auspices of the International Council for Industrial and Applied Mathematics.From August 10 to 14,2015,mathematicians,scientists     

Boundedness for commutators of multipliers on Hardy type spaces

In this paper, we study the commutators generalized by multipliers and a BMO function. Under some assumptions, we establish its boundedness properties from certain atomic Hardy space Hb^p（R^n） into the Lebesgue space L^p with p 〈 1.     

A unified approach to certain problems of best local approximation

In this paper we study best local quasi-rational approximation and best local approximation from finite dimensional subspaces of vectorial functions of several variables. Our approach extends and unifies several problems concerning best local multi-point approximation in different norms.     

Towards Excellence in Science Chinese Academy of Sciences

<正>May 26,2014,Beijing Science is a human enterprise in the pursuit of knowledge.The scientific revolution that occurred in the 17th Century initiated the advances of modern science.The scientific knowledge system created by     

THE 8~(th) INTERNATIONAL CONGRESS ON INDUSTRIAL AND APPLIED MATHEMATICS

<正>August 10-14,2015Beijing,ChinaThe International Congress on Industrial and Applied Mathematics(ICIAM)is the premier international congress in the field of applied mathematics held every four years under the auspices of the International Council for Industrial and Applied Mathematics.From August 10 to 14,2015,mathematicians,scientists     

Bounds for the zeros of polynomials

Let P(z)=∑↓j=0↑n ajx^j be a polynomial of degree n. In this paper we prove a more general result which interalia improves upon the bounds of a class of polynomials. We also prove a result which includes some extensions and generalizations of Enestrǒm-Kakeya theorem.