浅谈正定二次型的习题课设计

在高等代数的实二次型内容中,正定二次型占有特殊的地位.本文从概念的回顾、正定二次型与正定矩阵的判断、二次型正定及矩阵正定的性质、其它类型二次型四个方面来设计正定二次型的习题课,并通过具体例子说明例题、习题精选的原则.     

强正定二次型与Weyl-Heisenberg 框架的构造

本文研究了一类具有特殊结构的无限维二次型, 得到这类二次型的对称矩阵是符号为多项式的模的平方的Laurent 矩阵, 进一步得到了这类二次型是强正定的判断标准以及一类Weyl-Heisenberg 框架的构造. 本文还研究了这类二次型的矩阵的所有有限维主对角子矩阵的强正定性, 并由此得到一类子空间Weyl-Heisenberg 框架的构造. 最后举例说明本文的主要结果及其应用. 本文建立了两个看似不相关的领域间的联系.     

关于二次型图的完美性

本文应用强完美图定理,解决了二次型图的完美图判别问题.     

实二次型的顺序主子式与惯性指数

在非零顺序主子式的最高阶数与实二次型秩相等的前提下,研究如何利用实二次型的顺序主子式序列来确定二次型所有可能的类型.给出Gundelfinger法则和Frobenius法则的简单证明.     

实二次型的顺序主子式与惯性指数

在非零顺序主子式的最高阶数与实二次型秩相等的前提下,研究如何利用实二次型的顺序主子式序列来确定二次型所有可能的类型.给出Gundelfinger法则和Frobenius法则的简单证明.     

矩阵的泛正定与广义逆偏序

引言出现在二次型和 Hermite 型研究中的正定矩阵不仅理论结果非常丰富,而且在几乎所有的数值分析以及应用数学和力学各分支中有着广泛的应用.我们用 P_n 表示所有 n 阶实正定阵的集合     

辛代数的不变双线性型

考察了辛代数和与它相联系的李三系的双线性型之间的关系,并证明了辛代数的反对称不变双线性型可以唯一扩张到与它相联系的李三系中.作为这种关系的一个应用,得到了二次辛代数是单辛代数的一个充要条件,并证明二次辛代数的唯一分解定理.     

关于一大类第二型曲线积分问题的教学札记

曲线积分计算往往存在技术性的困难,若利用"正交变换"(二次型)"等有关理论去解决这些计算问题,则往往有功效。文[1],[2]给出了正交变换(二次型)在重积分中应用。现将在多年的教学实践中,以"正交变换"为工具,处理了二元二次型的面积问题,简捷的处理了一大类第二型曲线积分的问题的教学方法整理出来。这些方法与结果不但对从事大学数学教学有一定的实用性,而且对从事金融数学的教学研究也有着一定参考价值.     

TD孤子方程族的可积耦合及其哈密顿结构

用拓展谱问题方法构造TD族的可积耦合,并应用二次型恒等式寻求拓展的TD族哈密顿结构.     

随机投影阵的二次型分布及其应用

对于以椭球等高分布为变量的二次型分布已有文章研究,这些结果在一般的线性模型和分布理论中特别重要,而投影阵在二次型的分布性质中起着很重要的作用。但这些文章所讨论的二次型、其中矩阵都是通常的常数矩阵。本文的目的是推广这些结果至二次型矩阵为随机的情况,得到了一些有趣的结果,同时,给出所得结果的一些应用。     

Affine-inscribed and affine-circumscribed polygons and polytopes

Five theorems on polygons and polytopes inscribed in (or circumscribed about) a convex compact set in the plane or space are proved by topological methods. In particular, it is proved that for every interior point O of a convex compact set in ℝ³, there exists a two-dimensional section through O circumscribed about an affine image of a regular octagon. It is also proved that every compact convex set in ℝ³ (except the cases listed below) is circumscribed about an affine image of a cube-octahedron (the convex hull of the midpoints of the edges of a cube). Possible exceptions are provided by the bodies containing a parallelogram P and contained in a cylinder with directrix P. Bibliography: 29 titles. Translated fromZapiski Nauchnykh Seminarov POMI, Vol. 231, 1995, pp. 286–298. Translated by B. M. Bekker.     

Partitions and pairwise sums and products

A seven cell partition of N is constructed with the property that no infinite set has all of its pairwise sums and products in any one cell. A related Ramsey Theory question is shown to have different answers for two and three cell partitions.     

Linear birth and death models and associated Laguerre and Meixner polynomials

We study birth and death processes with linear rates λ_n = n + α + c + 1, μ_{n + 1} = n + c, n 0 and μ₀ is either zero or c. The spectral measures of both processes are found using generating functions and the integral transforms of Laplace and Stieltjes. The corresponding orthogonal polynomials generalize Laguerre polynomials and the choice μ₀ = c generates the associated Laguerre polynomials of Askey and Wimp. We investigate the orthogonal polynomials in both cases and give alternate proofs of some of the results of Askey and Wimp on the associated Laguerre polynomials. We also identify the spectra of the associated Charlier and Meixner polynomials as zeros of certain transcendental equations.     

Distributive and Multiplication Modules and Rings

We study rings in which every ideal is a finitely generated multiplication right ideal.     

Beliefs and beyond: affect and the teaching and learning of mathematics

The importance of beliefs for the teaching and learning of mathematics is widely recognized among mathematics educators. In this special issue, we explicitly address what we call “beliefs and beyond” to indicate the larger field surrounding beliefs in mathematics education. This is done to broaden the discussion to related concepts (which may not originate in mathematics education) and to consider the interconnectedness of concepts. In particular, we present some new developments at the conceptual level, address different approaches to investigate beliefs, highlight the role of student beliefs in problem-solving activities, and discuss teacher beliefs and their significance for professional development. One specific intention is to consider expertise from colleagues in the fields of educational research and psychology, side by side with perspectives provided by researchers from mathematics education.