对称群在面饰分类中的应用

近年来,中学课本和研究型学习的课程中,都涉及到一些平面图形的对称性问题.这一问题可划分为两大类,第一类:图形的对称变换有不动点,比如正方形的中心,等腰(非等边)三角形底边上的高等等.第二类:图形的对称变换没有不动点,在这种情况下,平移一定包含其中,而图形一定是无限的.这一类型最简单的情况是,平移仅沿某一固定直线进行,称为带饰;一般的情况是,平移可同时沿某两条相交直线进行,称为面饰.面饰的十七种图形在古埃及的装饰绘画中就已经出现,近三百年来,随着群论的逐步建立和完善,人们对这一问题进行了严格的理论证明.这篇文章是北京师范大学数学科学学院的本科毕业论文,郭佳意和董正林同学利用对称群的知识介绍了面饰的分类,给出了全部十七种面饰的生成元和定义关系,希望能够对中学老师和同学们有所启迪.     

半参数回归模型中小波估计的随机加权逼近速度

把小波光滑方法和随机加权方法结合在一起，获得了半参数回归模型中参数分量的小波估计的随机加权逼近速度为σ(n^-1/2)。因此，从大样本意义上说，小波光滑方法和随机加权方法对半参数回归模型是可用的。     

Integrable Bogoliubov Transform and Integrable Model

By defining Bogoliubov transform as a function of parameters,the integrability of the Bogoliubov transform in Parameter space is investigated.It is shown that integrable Bogoliubov transform is closely related to the known integrable model.The relation between the integrable Bogoliubov transform and geometric phase of vacuum induced by the Bogoliubov transform is also discussed.     

ZN规范理论修正的MK变换

本文导出了格点规范体系修正后的Migdal-Kadanoff递推关系,并对Z₄体系的相图进行了计算.结果表明得出的固定点和相图比用MK近似计算在数值上更接近于Monte Carlo模拟的结果.这说明修正后的递推关系比用MK关系更有意义.     

SUq(2)代数的广义量子相干态表示

本文给出了SU_q(2)代数的广义量子相干态表示,并指出由此可以得到SU_q(2)的一个新的Boson实现,这样的Boson实现是广义的q-Dyson实现,但这类实现是不厄米的,可以引入一个新的变换使之变为厄米的.这种变换后的实现可以称为q-Holstein-Primakoff实现.我们找出了这样的变换矩阵.文中也指出这种方法推广到高阶群似乎不很容易.     

EXISTENCE OF GLOBAL SMOOTH SOLUTION FOR SCALAR CONSERVATION LAWS WITH DEGENERATE VISCOSITY IN 2-DIMENSIONAL SPACE

This article concerns the existence of global smooth solution for scalar conservation laws with degenerate viscosity in 2-dimensional space. The analysis is based on successive approximation and maximum principle.     

Frame Wavelets with Compact Supports for L^2（R^n）

The construction of frame wavelets with compact supports is a meaningful problem in wavelet analysis. In particular, it is a hard work to construct the frame wavelets with explicit analytic forms. For a given n × n real expansive matrix A, the frame-sets with respect to A are a family of sets in R^n. Based on the frame-sets, a class of high-dimensional frame wavelets with analytic forms are constructed, which can be non-bandlimited, or even compactly supported. As an application, the construction is illustrated by several examples, in which some new frame wavelets with compact supports are constructed. Moreover, since the main result of this paper is about general dilation matrices, in the examples we present a family of frame wavelets associated with some non-integer dilation matrices that is meaningful in computational geometry.     

智能型表面测振系统

本文采用加速度传感器测量振动频谱的原理，对表面振动测量系统的实现进行了较为详细的描述，并用所研制的测振系统进行了实际测量，得到较为理想的实验结果．     

数学分析中的两种基本思想方法—转换与估值

数学分析中的两种基本思想方法──转换与估值邝荣雨（北京师范大学数学系１００８７５）本文试图从方法论的角度，就数学分析的基本内容和基本解题方法进行提炼、归纳和总结．我们称它为数学分析的基本思想方法．我认为它主要包含两种方法：转换（或称变换）方法和估值方...