以线性空间和线性映射为核心的线性代数体系——高等数学教学内容与体系改革系列谈（之二）

这个专题谈谈为什么线性代数的教学不从行列式、矩阵、线性方程组开始，而从线性空间、线性映射开始?这是考虑到线性代数的教学对提高学生效学素质的独特作用，也由于线性空间和线性映射是线性代数的校心内容理应在线性代数中占核心地位，以线性空间和线性映射为纲贯穿线性代数的各章内容使之形成既有一定独立性又有有机联系的整体。     

一道线性代数习题的教学处理

研究向量组的线性相关性或线性无关性，是线性代数课程的重要内容之一．由于它的概念高度抽象、基本理论相对集中，因而也是理工科线性代数的教学难点之一，为了进一步巩固和强化课堂教学效果，帮助学生深刻理解基本概念，熟练掌握基本理论，提高抽象思维能力，笔者利用习题课这一教学环节，组织了一次别开生面的专题教学活动，收效显著，反响颇佳。     

线性代数与微积分学问题与解法的渗透

通过典型的线性代数问题与微积分学问题,就其问题解法上的相互渗透进行探讨,初步揭示大学理工科各专业的两门重要的基础课线性代数与微积分学它们之间密切的联系.     

悬臂梁大挠度问题的双参数摄动解

利用拟线性分析方法中的一阶导数代换对基本方程进行了简化处理,将基本的微分积分方程转化为非线性代数方程组,并结合双参数摄动研究了悬臂梁的大挠度问题．与已有的研究结果比较表明: 将拟线性方法用于研究悬臂梁的大挠度问题,计算较为简便, 同时又具有良好的精度．     

线性代数中几个疑难问题的处理

基于东南大学线性代数课程的教学实践,本文针对递归数列与行列式、矩阵的初等列变换与列向量组等价、条件的独立性以及线性代数与解析几何的联系这四个方面的问题,提出了处理方案.     

关于矩阵的初等变换运用的一则注记

矩阵的初等变换是线性代数学中应用广泛的基本工具之一,目前一般线性代数或高等代数教材中常见之于用来解线性方程组,求秩,求逆,解矩阵方程(如A、B可逆时解AX=C,YB=C或AZB=C等),化二次型为标准形(或规范形),求由一组基底到另一组基底的过渡矩阵等     

线性映射视角下矩阵的秩

向量空间之间的线性映射是线性代数研究的主要内容之一.从线性映射的视角考察线性代数知识可以更清晰地认识线性代数中重要知识点的本质.利用线性映射知识,对矩阵秩的几个重要命题给出了比较简洁的证明.     

工科线性代数流行教材的失误及修改意见

近年讲授工科线性代数，发现流行教材普遍存在一些失误，有的还很严重．为减少其不良影响，本文特提出若干修改意见，供讲课教师和教材编者参考．一、有的教材错把行列式法当重点，引偏方向．建议：早点、重点讲述初等变换法．众所周知，线性代数基本问题，如求逆矩阵，解...     

应用初等变换解决向量的线性表出问题

应用初等变换解决向量的线性表出问题雷英果（福州大学）由于向量的加、减、数乘运算是线性代数的基本运算。初等变换在线性代数中起着重要的作用。我们可以用初等变换计算行列式，求矩阵的逆，计算矩阵的秩，解线性方程组，化矩阵为对角形，．．．等等。但是，在求解把向...     

浅析基矩阵在线性代数教学中的应用

主要研究基矩阵在线性代数教学中的应用.具体讨论基矩阵在矩阵乘法运算的几何意义、乘法运算律、线性空间等方面的教学中的应用.旨在提高线性代数的教学质量.     

The learning and teaching of linear algebra: Observations and generalizations

This paper is about a teaching experiment (TE) with inservice secondary teachers (hereafter “participants”) in the theory of systems of linear equations. The TE was oriented within particular social and intellectual climates, and its design and implementation took into consideration a series of findings concerning the difficulties students have in linear algebra. The questions we set for this study were: (1) Did the participants in the particular TE climates construct viable knowledge in the theory of systems of linear equations? Our criteria for viable knowledge consist in evidence for the ability to (a) generate non-trivial conjectures, judged so subjectively by a mathematician, (b) prove such conjecture, and (c) move upward along the APOS conception levels. (2) What difficulties and insights did the participants experience as they constructed such knowledge?The potential contributions of our investigation into these questions to researchers and practitioners include (a) a detailed depiction of the participants’ achievements and challenges in dealing with theoretical questions concerning linear systems in an authentic learning environment and under a tutelage oriented in a particular constructivist perspective; and (b) a field-based hypothesis about the consequences of a particular learning environment vis-à-vis construction of knowledge in linear algebra.All of the participants had taken a linear algebra course as part of their undergraduate studies, on average 17 years prior to the TE, with an average grade of about 80%. Thus, a third question set for this study concerns retention. (3) What did the participants retain from their linear algebra courses vis-à-vis concepts, ideas, and problem solving pertaining to the theory of systems of linear equations, assuming they had constructed such knowledge during these courses?     

Eigenvalues of LRU via a linear algebraic approach

In this short paper we analyze the Markov Chain associated with Least Recently Used (LRU) cache replacement scheme. The eigenvalues and their multiplicities of this chain are determined using basic linear algebra along with induction.     

Symmetrized-lexicographic order and the method of points

A variant of lexicographic order called symmetrized-lexicographic order is defined. The symmetrized-lexicographic order finds its application in the goal programming procedure called the method of points. The symmetrized-lexicographic order is shown to be representable using linear algebra and, thus, the method of points can be implemented as a linear programming problem.     

Analyzing student understanding in linear algebra through mathematical activity

In this paper we characterize students’ conceptions of span and linear (in)dependence and their mathematical activity to provide insight into their understanding. The data under consideration are portions of individual interviews with linear algebra students. Grounded analysis revealed a wide range of student conceptions of span and linear (in)dependence. The authors organized these conceptions into four categories: travel, geometric, vector algebraic, and matrix algebraic. To further illuminate participants’ conceptions of span and linear (in)dependence, the authors developed a categorization to classify the participants’ engagement into five types of mathematical activity: defining, proving, relating, example generating, and problem solving. Coordination of these two categorizations provides a framework that proves useful in providing finer-grained analyses of students’ conceptions and the potential value and/or limitations of such conceptions in certain contexts.     

Fundamental Solutions of Linear Differential Equations in the Sense of Mnemofunctions

In this paper we discuss the definition and construction of the fundamental solution of a linear differential equation with constant coefficients in the algebra of mnemofunctions. This algebra contains the tempered distributions. We also present some examples including a physical illustration of our results for the equation u = .     

套子代数上线性映射的Lie不变子空间

本文引入了Banach代数上线性映射的Lie不变子空间,给出了因子VonNeumann代数中套子代数上以导子空间为Lie不变子空间的线性映射的一般形式,研究了Lie导子与Lie自同构的概念及了Lie导子与Lie自同构半群的关系.     

A review of formal orthogonality in Lanczos-based methods

Krylov subspace methods and their variants are presently the favorite iterative methods for solving a system of linear equations. Although it is a purely linear algebra problem, it can be tackled by the theory of formal orthogonal polynomials. This theory helps to understand the origin of the algorithms for the implementation of Krylov subspace methods and, moreover, the use of formal orthogonal polynomials brings a major simplification in the treatment of some numerical problems related to these algorithms. This paper reviews this approach in the case of Lanczos method and its variants, the novelty being the introduction of a preconditioner.     

三个矩阵秩不等式的多种证明

针对线性代数课程教学中三个矩阵秩的不等式的证明展开研究,对每一个不等式,分别给出相应的证明。     

Interactionist perspective on negotiation processes of students’ different understandings during small group work on linear algebra

Student group work represents a central learning setting within mathematics programs at the university level. In this study, a theoretical perspective on collaboration is adopted in which the differences between students’ interpretations of a mathematical concept are seen as an opportunity for individual restructuring processes. This so-called interactionist perspective is applied to student group work on linear algebra. The concepts of linear algebra at the university level are characterized by a versatility of different modes of expression and interpretation. For students of linear algebra, the flexible transitions between the different interpretations of linear algebra concepts usually pose a challenge. This study focuses on how students negotiate their different interpretations during group work on linear algebra and how transitions between interpretations might be stimulated or hindered. Video recordings of eight student groups working on a task that required flexible transition between interpretations of homomorphisms were sampled. The recordings were analyzed from an interactionist perspective, focusing on interaction situations in which the participating students expressed and negotiated different interpretations of homomorphisms. The analyses of students’ interactions highlight a phenomenon whereby differences in students’ interpretations remain implicit in group discussions, which constitutes an obstacle to the negotiation process.