Representation in Computational Environments: Epistemological and Social Distance

Computational environments have the potential to provide new representational resources and new ways of supporting teaching and learning of mathematics. In this paper, we seek to characterize relationships between the representations offered by particular technologies and other representations commonly available in the classroom context, using the notion of ‘distance’. Distance between representations in different media may be epistemological, affecting the nature of the mathematical concepts available to students, or may be social, affecting pedagogic relationships in the classroom and the ease with which the technology may be adopted in particular classroom or national contexts. We illustrate these notions through examples taken from cross-experimentation of computational environments in national contexts different from those in which they were developed. Implications for the design and dissemination of computational environments for use in learning mathematics are discussed.     

Epistemological messages conveyed by three high-school and college mathematics textbooks

Mathematics textbooks embody a particular set of assumptions about mathematics or the mathematics intended for students at a particular level. Thus, an epistemological analysis of textbooks can provide some context for understanding, for example, the difficulties many students encounter when moving from high-school to collegiate mathematics. In this study, we consider how typical pre-calculus, calculus, and analysis texts treat the topic of continuity. We find that these texts send conflicting messages regarding the status and purpose of mathematical definitions.     

Epistemological Skepticism, Semantic Blindness, and Competence-Based Performance Errors

The semantic blindness objection to contextualism challenges the view that there is no incompatibility between (i) denials of external-world knowledge in contexts where radical-deception scenarios are salient, and (ii) affirmations of external-world knowledge in contexts where such scenarios are not salient. Contextualism allegedly attributes a gross and implausible form of semantic incompetence in the use of the concept of knowledge to people who are otherwise quite competent in its use; this blindness supposedly consists in wrongly judging that there is genuine conflict between claims of type (i) and type (ii). We distinguish two broad versions of contextualism: relativistic-content contextualism and categorical-content contextualism. We argue that although the semantic blindness objection evidently is applicable to the former, it does not apply to the latter. We describe a subtle form of conflict between claims of types (i) and (ii), which we call différance-based affirmatory conflict. We argue that people confronted with radical-deception scenarios are prone to experience a form of semantic myopia (as we call it): a failure to distinguish between différance-based affirmatory conflict and outright inconsistency. Attributing such semantic myopia to people who are otherwise competent with the concept of knowledge explains the bafflement about knowledge-claims that so often arises when radical-deception scenarios are made salient. Such myopia is not some crude form of semantic blindness at all; rather, it is an understandable mistake grounded in semantic competence itself: what we call a competence-based performance error.     

Some didactical and Epistemological Considerations in the Design of Educational Software: The Cabri-euclide Example

We propose to use didactical theory for the design of educational software. Here we present a set of didactical conditions, and explain how they shape the software design of Cabri-Euclide, a microworld used to learn “mathematical proof ” in a geometry setting. The aim is to design software that does not include a predefined knowledge of problem solution. Key features of the system are its ability to verify local coherence, and not to apply any global and automatic deduction.     

Epistemological beliefs concerning the nature of mathematics among teacher educators and teacher education students in mathematics

Beliefs constitute a central part of a person’s professional competences as beliefs are crucial to the perception of situations and as they influence our choice of actions. The present article focuses on epistemological beliefs about the nature of mathematics among future teachers and their educators at university and post-university teacher-training institutions in Germany. The data reported are part of a larger sample originating from the MT21 study [supported by the National Science Foundation through a grant to W. S. Schmidt and M. T. Tatto (REC-0231886). MT21 started in 2003] which explores and compares mathematics teacher education in Bulgaria, Germany, Mexico, South Korea, Taiwan, and the United States. In this article, we examine the structure and level of beliefs concerning the nature of mathematics for teacher education students in Germany both at the beginning (n = 368) and the end of their education (n = 286) as well as their educators (n = 77) in three academic disciplines (mathematics, mathematics pedagogy and general pedagogy). In the first part of the article, the literature on epistemological beliefs and their structure will be reviewed. In the empirical part, analyses on the level and the structure of beliefs for our samples and subsamples will be presented. Relations between educators’ and students’ beliefs will be explored.     

The New Riddle of Induction and the New Riddle of Deduction

Many believe that Goodman’s new riddle of induction proves the impossibility of a purely syntactical theory of confirmation. After discussing and rejecting Jackson’s solution to Goodman’s paradox, I formulate the “new riddle of deduction,” in analogy to the new riddle of induction. Since it is generally agreed that deductive validity can be defined syntactically, the new riddle of induction equally does not show that inductive validity cannot be defined syntactically. I further rely on the analogy between induction and deduction in order to explain why some predicates, such as “grue,” are unprojectible.     

S-Module and the New Massey-Product

In this paper, we give the definition ofS-Module and with this module theory prove the properties of the new Massey-product defined in [6]. As an application, we find new relations ofh_iandb_jin theE₂-term of the classical Adams spectral sequence.     

Old and New on the Laplace-Beltrami Derivative

The (strong) Laplace-Beltrami derivative and related operators appear quite frequently in many problems involving Fourier series, spherical harmonics, approximation of functions and smoothness. This article intends to provide an overview with updates on such operators. While most of the results concerning the Laplace-Beltrami derivative found in the literature are stated in the three-dimensional setting, our approach includes higher-dimensional spheres. We present proofs for results which are labeled as known but are just mentioned elsewhere. Spherical moduli of smoothness and decay rates for eigenvalues of integral operators are also among the covered topics.     

关于《中国城镇新增用地供给量的预测及其修正方法》的新模型建立及其比较

本文对文献［１］中的数据重新以时间序列为变量建立回归模型,通过比较新老模型的检验效果,显示新模型的优良性．又结合新模型重新给出了更为合理的新增用地控制方法     

一些新数列的偏差与伪随机性

设p为奇素数,x为整数且满足1≤x≤p-1．定义数列其中■是n模p的乘法逆,满足n■≡1 mod p以及1≤■≤p-1．证明了(x_n)是一致分布数列,(e_n)是好的伪随机数列．这表明在二进制数列与[0,1)数列之间存在某种联系．     

一些新数列的偏差与伪随机性

设P为奇素数,x为整数且满足1≤x≤P-1.定义数列xn={{(n)+(n+x)/p},如果p(|)n(n+x),0,其它以及en={+1,如果p(|)n(n+x)且0≤{(n)+{(n)+(n+x)}＜1/2,-1,如果p(|)n(n+x)且1/2≤{(n)+{(n)+(n+x)}＜1,+1,如果p|n(n+x),其中瓦是(n)模p的乘法逆,满足n(n)≡1 mod p以及1≤(n)≤p-1.证明了(xn)是一致分布数列,(en)是好的伪随机数列.这表明在二进制数列与[0,1)数列之间存在某种联系.     

关于一维Moran集Hausdorff维数的一个新证明和 一个新结果

利用分形儿何中的技巧给出了关于一维Moran集Hausdorff维数的一个新证明和一个新结果,这可看做是对原有结果的一个有益补充.