关于映射同伦类的拓扑熵

设ｆ：Ｔ＾ｍ→Ｔ＾ｍ为ｍ维环面自映射，Ｎ＾∞（ｆ）是ｆ的渐近Ｎｉｅｌｓｅｎ数，本文应用Ｎｉｅｌｓｅｎ不动点理论，给出了ｌｏｇＮ＾∞（ｆ）是ｆ的同伦类的拓扑熵的最好下界的一个充要条件；并通过在齐性空间上引入等价度量，将此结论推广到了幂零流形自映射的情形。     

环的自映射的最少周期点数

设Ｘ是一个紧致连通的ＡＮＲ＇ｓ，ｆ：Ｘ→Ｘ是连续映射。于是ｆ有Ｎｉｅｌｓｅｎ型数，ＮＦｎ（ｆ），它是数集｛＃Ｆｉｘ（ｇ＾ｎ）ｇ－ｆ｝的下界。本文在Ｘ是环时，给出ＮＦｎ（ｆ）是该数集的下确界，即存在连续映射ｇ＝ｆ，使得＃Ｆｉｘ（ｇ＾ｎ）＝ＮＦｎ（ｆ）的一个充分条件。     

广义Hammerstein型方程的存在定理

本文利用单调型强制映射满射性和逼近方法建立了广义Ｈａｍｍｅｒｓｔｅｉｎ型方程ｕ＋Ｋ（ｕ）Ｆ（ｕ）＝０解的存在性定理，这里对于实自反Ｂａｎａｃｈ空间Ｘ的共轭空间Ｘ^*的每个ｕ，Ｋ（ｕ）：Ｘ→Ｘ^*是线性映射，Ｆ：Ｘ^*→Ｘ是任一映射．所得结果推广了Ｓｃｈｉｌｉｎｇ，Ｓｒｉｋａｎｔｈ ａｎｄ Ｊｏｓｈｉ等相应的结果     

单纯形上Bernstein多项式的一些性质

设Ｂ_m（ｆ，·）为函数ｆ在ｄ维单纯形σ上的ｎ阶Ｂｅｒｎｓｔｅｉｎ多项式，本文对ｆ∈Ｃ^ｒ（σ）及ｆ∈Ｃ^r+2（σ）给出了ｆ的各阶编导数用Ｂ_n（ｆ，·）相应偏导数逼近的误差估计．同时也考虑了整系数Ｂｅｒｎｓｔｅｉｎ多项式的Ｌ_p模估计     

不动点大类与 Nielsen数

通过引进 π１ （ Ｘ,ｘ０ ） 的同态 ｆπ 的不动子群 Ｆｉｘｆπ,在 Ｈ ＝ Ｆｉｘｆπ ·ｋｅｒｆ π为π１ （ Ｘ,ｘ０ ） 的正规子群时定义了不动点大类,得到不动点大类数是有限的．在曲面 Ｘ的正则复迭空间 Ｘ Ｈ 为有限叶时只要姜子 群相对于 Ｈ 极大,ｆ 的 Ｎｉｅｌｓｅｎ 数就可以用一维同调群计算     

关于一类S1，13（△（2）mn）插值与逼近

设△^（2）_mn是矩形域Ｄ＝［ａ，ｂ］(?)［ｃ，ｄ］的Ⅱ－型三角剖分．S^1，1₃（△^（2）_mn）是带边界条件的二元三次样条空间：本文我们将讨论一类S^1，1₃（△^（2）_mn）的插值问题，证明了它的存在性，唯一性及逼近阶：如果ｆ∈Ｃ^４（Ｄ），则有｜ｆ－ｓ｜≤ｋ（ｌ）·ｍａ     

k维环面上坐标自映射下拓扑熵的一个下界

给出了ｋ维环面上坐标自映射下拓扑熵的一个下界，最后，还指出了ｋ维环面上渐近Ｒｅｉｄｅｍｅｉｓｔｅｒ数严格大于渐近Ｎｉｅｌｓｅｎ数的情形，并说明了文（３）（或文（４）中引理１为该文的一个特例。     

一类拟线性椭圆型偏微分方程的先验界的估计

近几年对边值问题－ｄｉｖ（｜Ｄｕ｜^p-2Ｄｕ）＝λｆ（ｕ）｝在Ω上ｕ｜(?)Ω＝０正解方面已经得到了许多结果．这里λ＞０，Ω是有界区域和对ｓ≥０，ｆ（ｓ）≥０．在本文中在条件Ｎ≥ｐ＞１，Ω＝Ｂ_１＝｛ｘ∈Ｒ^N，｜ｘ｜＜１｝和ｆ∈Ｃ¹（０，∞）∩Ｃ⁰（［０，∞）），ｆ（０）＝０，研究了这类问题的正对称解的先验界估计．     

l-群的极小素子群

本文研究l-群的极小素子群,主要证明如下结果:设G是一个l-群.（1）N∈Γ_m（G）,则N=a^⊥当且仅当{P_N^C}是一个归纳集;（2）g∈G⁺,如果g是特殊的,且g的唯一值是原子,则g^⊥∈Γ_m（G）;（3）G∈B_w,Γ₁（C）是原子的当且仅当Γ_m(G）?Γ₁（G）。     

一类实奇芽等价的充要条件

给定一自反的Ｂａｎａｃｈ空间Ｘ．在ｃ^∞函数芽环∈（Ｘ）中,任何在原点Ｏ∈Ｘ的实奇芽ｆ,若其二阶Ｆｒｅｃｈｅｔ导数ｆ″（０）＝Ｔ是一个Ｆｒｅｄｈｏｌｍ算子,则它同构于形如：1/2+g(v)的一个芽．如果代替ｇ以一个与之同构的芽ｇ_１,显然得到一个与原来的芽同构的芽．然而,其逆是否真呢？本文将证明其逆命题亦真     

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.     

On a class of self-similar processes with stationary increments in higher order Wiener chaoses

We study a class of self-similar processes with stationary increments belonging to higher order Wiener chaoses which are similar to Hermite processes. We obtain an almost sure wavelet-like expansion of these processes. This allows us to compute the pointwise and local Hölder regularity of sample paths and to analyse their behaviour at infinity. We also provide some results on the Hausdorff dimension of the range and graphs of multidimensional anisotropic self-similar processes with stationary increments defined by multiple Wiener–Itô integrals.     

A REPRESENTATION FORMULA RELATED TO SCHR(O)DINGER OPERATORS

Schr(o)dinger operator is a central subject in the mathematical study of quantum mechanics.Consider the Schrodinger operator H = -△ V on R, where △ = d2/dx2 and the potential function V is real valued. In Fourier analysis, it is well-known that a square integrable function admits an expansion with exponentials as eigenfunctions of -△. A natural conjecture is that an L2 function admits a similar expansion in terms of "eigenfunctions" of H, a perturbation of the Laplacian (see [7], Ch. Ⅺ and the notes), under certain condition on V.     

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.     

On a class of Riemann surfaces

It is considered the class of Riemann surfaces with dimT1 = 0, where T1 is a subclass of exact harmonic forms which is one of the factors in the orthogonal decomposition of the spaceΩH of harmonic forms of the surface, namely The surfaces in the class OHD and the class of planar surfaces satisfy dimT1 = 0. A.Pfluger posed the question whether there might exist other surfaces outside those two classes. Here it is shown that in the case of finite genus g, we should look for a surface S with dimT1 = 0 among the surfaces of the form Sg\K , where Sg is a closed surface of genus g and K a compact set of positive harmonic measure with perfect components and very irregular boundary.     

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     

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