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[H2o] 蛋疼了,翻译了一个Perface

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Preface
In most mathematics progra***inear algebra is taken in the ¯rst or second
year, following or along with at least one course in calculus. While the location
of this course is stable, lately the content has been under discussion. Some instructors
have experimented with varying the traditional topics, trying courses
focused on applications, or on the computer. Despite this (entirely healthy)
debate, most instructors are still convinced, I think, that the right core material
is vector spaces, linear maps, determinants, and eigenvalues and eigenvectors.
Applications and computations certainly can have a part to play but most mathematicians
agree that the themes of the course should remain unchanged.
Not that all is ¯ne with the traditional course. Most of us do think that
the standard text type for this course needs to be reexamined. Elementary
texts have traditionally started with extensive computations of linear reduction,
matrix multiplication, and determinants. These take up half of the course.
Finally, when vector spaces and linear maps appear, and de¯nitions and proofs
start, the nature of the course takes a sudden turn. In the past, the computation
drill was there because, as future practitioners, students needed to be fast and
accurate with these. But that has changed. Being a whiz at 5£5 determinants
just isn't important anymore. Instead, the availability of computers gives us an
opportunity to move toward a focus on concepts.
This is an opportunity that we should seize. The courses at the start of
most mathematics programs work at having students correctly apply formulas
and algorithms, and imitate examples. Later courses require some mathematical
maturity: reasoning skills that are developed enough to follow di®erent types
of proofs, a familiarity with the themes that underly many mathematical investigations
like elementary set and function facts, and an ability to do some
independent reading and thinking, Where do we work on the transition?
Linear algebra is an ideal spot. It comes early in a program so that progress
made here pays o® later. The material is straightforward, elegant, and accessible.
The students are serious about mathematics, often majors and minors.
There are a variety of argument styles|proofs by contradiction, if and only if
statements, and proofs by induction, for instance|and examples are plentiful.
The goal of this text is, along with the development of undergraduate linear
algebra, to help an instructor raise the students' level of mathematical sophistication.
Most of the di®erences between this book and others follow straight
from that goal.
One consequence of this goal of development is that, unlike in many computational
texts, all of the results here are proved. On the other hand, in contrast
with more abstract texts, many examples are given, and they are often quite
detailed.
Another consequence of the goal is that while we start with a computational



1楼2012-08-17 17:15回复
    并不是所有人都适合传统课堂,我们大多数认为课堂的标准文本类型需要被重新考量,传统的初学者文本开始于线性简化、矩阵乘法和行列式的大量计算,这占据了一半的课堂时间,最终,当向量空间和线性图、定义和推理出现时,课程的本质有了一个突然的转变,过去,计算训练出现是由于:作为未来的实践者,学生需要更快和更精确的计算,但是现在改变了,成为一个计算 5x5行列式的高手不再重要。取而代之,电脑的可用性使我们更注重于概念。
    这个机会我们需要抓住,很多数学工程的课程之初致力于让学生正确的应用公式和演算法和模仿例子,随后的课程要求一些计算能力的成熟:娴熟的能应对不同类型的推理技能,熟悉深度数学研究的主题,独立阅读和思考的能力。我们在何处去过渡呢?
    线性代数是一个理想点,早期它来到课堂所以不久就有收获,材料内容直接、优雅和易用,学生或多或少对数学认真。有大量的争论在反证法、如果或仅仅陈述和归纳证明,有很丰富的例子。
    这个文本的目标是沿着大学线性代数的发展帮助导师提升学生的数学推论能力级别。这是这本书不同于其他直接追随目标的书。
    一个发展目标的结果是所有的结果都被证明了,不像很多的计算相关文本。另一方面,与很多抽象的文本不同,很多例子一旦被给予,它们通常很详细。
    另一个结果是当我们开始计算相关的主题时,线性简化,首先我们做的最多的不是计算。线性系统的解决很快被解决而且很完美,提供每件事情(这些证明可核查),削减阶梯形式的所有方法。尤其,在第一章,有机会呈现一点仔细查看记账细节的争论的推理证明,所以随后当推理需要时(例如:证明所有有限空间的向量空间的基本有相同数目的成员)这将是熟悉的。
    然而,另一个结果是第二章突然使用这个背景作为实向量空间的动力。这通常发生在第三个星期的结尾,我们不会停止去介绍矩阵乘法和行列式。取而代之,这些主题自然呈现在线性表定义后的发展中。
    为了帮助学生们从早起的课堂中过渡,这里的表现强调动力和自然。第三章是一个例子,在线性图上,没有像其他书那样从同型体的定义出发,这是因为定义很容易对一些相似的空间的观察而被发现,此后,下一节做了一个通过隔离“操作-保存”的方法来定义同态的方法,一点数学的巧妙被丢失,但是学生反过来获得了敏感上的大进步。
    文本中有大量的动力导致时间压力,在每节课前,我要求学生们预习一下书本,他们更好的跟随课堂因为有一些对材料的先前接触。例如,我能够单独一节课围绕着定义开始,因为我知道学生们对讲述的是什么有了解。书不能够替代导师,不过,一本很有用的书为例子和问题给导师更多的课堂时间讲解。
    很多学生的进步发生在练习中,这里的练习在其余的内容中,还有计算,这里有很多的证明。这从简单的检验到很多混乱的争论传播出了可接近的范围,甚至少量相当遇有挑战性的迷惑难题从引例、各种杂志、竞赛或问题收集中(作为部分乐趣,这些创造性的用词被保留越多越好)被带入到练习中。总之,这些问题的目标是养成一种能力和帮助学生体验做数学的压力。


    3楼2012-08-17 17:15
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      想喷么? @candy76041820
      


      4楼2012-08-17 17:17
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        好了,@candy76041820
        优越找够了吧,心里也舒服了吧。


        8楼2012-08-18 13:55
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