课程时间：2014年春季
授课教授：DYY

这门课的Grade：Grade神

这门课实在太水，本来不想写cwiki的...但是发现了notes中一处严重的错误...姑且发上来以免上课的人误入歧途
数论一章，Lemma 2.1和Theorem 2.3其实是循环论证...正确的做法是先证Theorem 2.3再证Lemma 2.1...Theorem 2.3的正确做法为

We can let x, y, y' belong to Z_n, such that
x *_n y = y *_n x = 1
x *_n y' = y' *_n x = 1



It suffices to show y = y'
This is easy since
y = y *_n 1 = y *_n (x *_n y') = (y *_n x) *_n y' = 1 *_n y' = y'
So this finishes the proof.


(摘自发给dyy的邮件)


既然已经写了cwiki...姑且多说几句....
果然还是要怒赞代数框架下的数论...优美而简洁


反正3711的requirement可以waive...所以其实什么时候上都无所谓...