运用抽象度分析法进行高三数学复习的尝试

我国著名数学家徐利治教授在他的专著《数学抽象方法和抽象度分析法》中提出了“弱抽象”和“强抽象”的概念 .数学概念的弱抽象又称“扩张式抽象” ,即从原型中选取某一特征加以抽象 ,从而获得比原结构更广的结构 ,使原结构成为后者的特例 .我认为 ,数学概念的弱抽象对指导高三数学复习能起到举一反三 ,启迪创新的作用 .弱抽象法则的基本依据是“特征分离概括化原则”或简称“特征概括原则” ,它的运用包括下列步骤 :先将一个结构内容较丰富的原型进行分析 ,把其中某个或某类特性分离出来 ,用形式化的数学语言把它表述出来 ,然后通过概括原…     

初中数学核心素养中的抽象能力培养

数学本身就是具有抽象性的学科,因此培养学生的抽象能力对于学习数学来说是很重要的,数学中很多的概念、定理以及数学分析能力都是在抽象能力的基础上发展的,如果学生抽象能力过弱,那么在以后的数学学习中必然会遇到很多困难.但是目前的初中数学的抽象能力培养中,仍然存在着一些不足之处,这些都是学生未来的数学学习的隐患,对此很多教师开始思考解决策略,以提升学生的抽象能力,因此本文也对于初中数学中的抽象能力培养提出自己的一些建议.     

1958年5月号论数学的抽象和公理法

数学的特点之一在于它的抽象性.弗·恩格斯写道:数学的对象是“非常现实的资料”,但是它“表现于非常抽象的形式之中”. 不仅数学,而且任何其他科学都运用着科学的抽象,因为没有抽象就不可能有认识,但数学在这方面却占着特殊的地位.     

运用弱抽象方法进行解析几何教学的尝试

我国著名数学家徐利治教授在他的专著《数学抽象度概念与抽象度分析法》中 ,对数学抽象与数学抽象度分析法有着精辟的论述 ,“所谓弱抽象 ,也可以称做概念扩张式抽象 ,即以原型中选取某特征 (侧面 )加以抽象 ,从而获得比原结构更广的结构 ,使原结构成为后者的特例 .”“一般说来 ,被人们最先认识的一些较具体、较直观的事物对象 ,如果其内容结构(或概念内涵 )非常丰富 ,则成为弱抽象的原型 .”解析几何有很多素材是能够成为弱抽象的原型的 .圆、椭圆、双曲线、抛物线之间的内在联系 ,保证一些结论横向推广的可行性 ;解析几何的知识特点要求…     

关于高等工科数学概念的教学方法

<正> 概念是基础[1],对于数学“概念”更应该有体现其特征的教学方法。数学中的概念一般都是比较抽象的、思辨的,不便于阐明和学习,这是它的特征之一。初学者常常出现的毛病是概念不清、理解不透,要掌握它就更困难一些。这样,数学中某些概念的抽象性与学习     

精致概念抽象过程 提升数学抽象素养——以“函数的单调性”教学为例

数学概念课堂教学过程中,应通过精心设置的问题,努力揭示数学概念的本质,利用师生课堂有效对话,适当地拉长概念的抽象过程,使概念的抽象过程更加精细、更加精致,在概念精致的过程中让学生深刻体会概念的抽象过程,从而使得数学抽象素养得以提升,本文以“函数的单调性”教学为例进行说明.     

运用弱抽象教学法的尝试

我国著名数学家徐利治教授在他的专著<数学抽象度概念与抽象度分析法>中,对数学抽象与数学抽象度分析法有着精辟的论述:弱抽象是指概念扩张式抽象,即从原型中选取某些特征(侧面)加以抽象,从而获得比原结构更广的结构,使原结构成为后者的特例.弱抽象的原型往往来自某些较具体又直观的事物对象,其丰富的内容结构或概念内涵使它具备成为弱抽象的原型.数学中有很多素材具备成为弱抽象原型的特征,如圆、椭圆、双曲线、抛物线之间的密不可分的联系,使一些结论的横向、纵向推广具备足够的可行性,可将一些特殊的点或直线一般化,把具体的数字形式化,将静止的曲线运动化,掌握静中探动、动中求静、动静结合的策略,从中提炼出能具体认识发展规律的素材,这有利于培养学生的探究能力、发散思维能力、创新能力.     

基于APOS理论的概念教学设计——以“实数”教学为例

数学具有抽象概括性，因此数学教学要遵循这一特点；APOS理论基于数学抽象性的特点，将数学概念的学习概括为操作或活动、过程、对象、概型四个阶段.本文中以初中数学“实数”的教学为例，得到基于APOS理论为框架数学概念教学的教学设计.     

抽象函数问题的求解策略

1抽象函数问题抽象函数专指没有给出具体的函数解析式或图象,只给出函数所满足的部分性质、运算法则或特殊条件的一类函数·由于此类函数问题既能考查学生对函数概念、性质的全面掌握情况,又能考查学生的代数推理、论证能力,还能考查学生对数学符号语言的阅读理解和综合运用能力以及对“一般”与“特殊”的辩证关系的认识能力,对发展学生思维能力,进行数学思维方法的渗透有较好的作用,因此而成为高考的一大命题热点,在近几年的高考中频频出现·2求解策略抽象函数问题,由于其本身所具有的模型抽象和给出的性质的隐蔽性,使得它的求解没有常规方法·这类问题的解法常常涉及到函数的概念和各种性质,因而具有抽象性、综合性和技巧性等特点·解题时需要通过对题目的信息作出具体分析与研究,根据不同的性质条件采用不同的方法和手段,可用的方法与手段有·2·1赋值代换法在许多情况下,抽象函数问题中往往会给出函数所满足的等式或不等式,因此在解决此类抽象问题时,赋值代换是一个最基本、最重要的策略:在所给函数式中,对所要证明或求解的式子作结构上分析,在函数的定义域内对自变量采取对应的代换赋值,使所要证明或求解式子的结构与已知式的结构趋于相同,以帮助我们达到变形化简的目的·...     

在概念性教学过程中发展数学抽象核心素养

根据维果茨基提出的“最近发展区”思想,阐述在概念性教学过程中如何发展学生的数学抽象核心素养,提升学生的数学抽象思维,并结合教学案例“对数的概念”谈谈“最近发展区”思想在概念性教学中的应用,提出一些建议.     

Designing for Mathematical Abstraction

Our focus is on the design of systems (pedagogical, technical, social) that encourage mathematical abstraction, a process we refer to as designing for abstraction. In this paper, we draw on detailed design experiments from our research on children’s understanding about chance and distribution to re-present this work as a case study in designing for abstraction. Through the case study, we elaborate a number of design heuristics that we claim are also identifiable in the broader literature on designing for mathematical abstraction. Our previous work on the micro-evolution of mathematical knowledge indicated that new mathematical abstractions are routinely forged in activity with available tools and representations, coordinated with relatively na?ve unstructured knowledge. In this paper, we identify the role of design in steering the micro-evolution of knowledge towards the focus of the designer’s aspirations. A significant finding from the current analysis is the identification of a heuristic in designing for abstraction that requires the intentional blurring of the key mathematical concepts with the tools whose use might foster the construction of that abstraction. It is commonly recognized that meaningful design constructs emerge from careful analysis of children’s activity in relation to the designer’s own framework for mathematical abstraction. The case study in this paper emphasizes the insufficiency of such a model for the relationship between epistemology and design. In fact, the case study characterises the dialectic relationship between epistemological analysis and design, in which the theoretical foundations of designing for abstraction and for the micro-evolution of mathematical knowledge can co-emerge.     

图的度序列

图的度序列是图论研究中一个重要的课题．至今已发表了４００余篇文章．本文概述这一课题的某些进展，其中包括了可图序列的判准、蕴含Ｐ可图序列和强迫Ｐ可图序列的一些主要结论，同时列出了一些有待进一步研究的问题．     

包含k-树图的毁裂度条件

连通图G的一个k-树是指图G的一个最大度至多是k的生成树.对于连通图G来说,其毁裂度定义为r(G)=max{ω(G-X)-|X|-m(G-X)|X■V(G),ω(G-X)1}其中ω(G-X)和m(G-X)分别表示G-X中的分支数目和最大分支的阶数.本文结合毁裂度给出连通图G包含一个k-树的充分条件;利用图的结构性质和毁裂度的关系逐步刻画并给出图G包含一个k-树的毁裂度条件.     

Recognition of logically related regions based heap abstraction

This paper presents a novel set of algorithms for heap abstraction, identifying logically related regions of the heap. The targeted regions include objects that are part of the same component structure (recursive data structure). The result of the technique outlined in this paper has the form of a compact normal form (an abstract model) that boosts the efficiency of the static analysis via speeding its convergence. The result of heap abstraction, together with some properties of data structures, can be used to enable program optimizations like static deallocation, pool allocation, region-based garbage collection, and object co-location.More precisely, this paper proposes algorithms for abstracting heap components with the layout of a singly linked list, a binary tree, a cycle, and a directed acyclic graph. The termination and correctness of these algorithms are studied in the paper. Towards presenting the algorithms the paper also presents concrete and abstract models for heap representations.     

连通图的度序列及连通平面图的低度点个数

美国数学家Bondy给出了一个非负整数序列为简单图的度序列的充要条件.本文对此进行了发展,证明了一个正整数序列为连通简单图的度序列的充要条件;然后在此基础上又探讨了平面图的低度点个数问题并定义了描述连通平面图的低度点个数的一个概念φ(n,m),并对某些低阶平面图求出了φ(n,m)的值.最后给出了φ(n,m)的上下界.     

The connected partition lattice of a graph and the reconstruction conjecture

Previously we showed that many invariants of a graph can be computed from its abstract induced subgraph poset, which is the isomorphism class of the induced subgraph poset, suitably weighted by subgraph counting numbers. In this paper, we study the abstract bond lattice of a graph, which is the isomorphism class of the lattice of distinct unlabelled connected partitions of a graph, suitably weighted by subgraph counting numbers. We show that these two abstract posets can be constructed from each other except in a few trivial cases. The constructions rely on certain generalisations of a lemma of Kocay in graph reconstruction theory to abstract induced subgraph posets. As a corollary, trees are reconstructible from their abstract bond lattice. We show that the chromatic symmetric function and the symmetric Tutte polynomial of a graph can be computed from its abstract induced subgraph poset. Stanley has asked if every tree is determined up to isomorphism by its chromatic symmetric function. We prove a counting lemma, and indicate future directions for a study of Stanley's question.     

定向可图的度偶序列

n为非负整数序列，若存在以该序列为度序列的图，则称n为可图的，特别的，若此图是一个定向图，该序列则称为是定向可图的，本提出了一个判断序列是否为定向可图的充分必要条件，并且在定理的证明过程中给出了一个在定理条件下构造所求定向图的有效算法。     

Change-of-bases abstractions for non-linear hybrid systems

We present abstraction techniques that transform a given non-linear dynamical system into a linear system, or more generally, an algebraic system described by polynomials of bounded degree, so that invariant properties of the resulting abstraction can be used to infer invariants for the original system. The abstraction techniques rely on a change-of-bases transformation that associates each state variable of the abstract system with a function involving the state variables of the original system. We present conditions under which a given change-of-bases transformation for a non-linear system can define an abstraction. Furthermore, the techniques developed here apply to continuous systems defined by Ordinary Differential Equations (ODEs), discrete systems defined by transition systems and hybrid systems that combine continuous as well as discrete subsystems.The techniques presented here allow us to discover, given a non-linear system, if a change-of-bases transformation involving degree-bounded polynomials yielding an algebraic abstraction exists. If so, our technique yields the resulting abstract system, as well. Our techniques enable the use of analysis techniques for linear systems to infer invariants for non-linear systems. We present preliminary evidence of the practical feasibility of our ideas using a prototype implementation.     

最大度为5的平面图是11-线性可染的

A linear coloring of a graph G is a proper vertex coloring such that the graph induced by the vertices of any two color classes is the union of vertex-disjoint paths.The linear chromatic number lc(G) o...     

带宽等于最小度的图的最小边数

本文对带宽等于最小度的图的边数极值问题进行了研究,主要结果如下:对任意给定的正整数n及r(r相似文献