Biology版 - Zhang, Yitang’s life at Purdue, by TT Moh |
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k******0
发帖数: 1073 | 1 Zhang, Yitang’s life at Purdue
(Jan. 1985-Dec, 1991)
T.T.Moh
1
Dr. Zhang Yitang made a major advancement to the twin prime conjec-ture as
verified by Prof. H. Iwaniec, a famous number theorist. Some people are
curious about Yitang’s life as a graduate student at Purdue University.As
the thesis adviser of Dr. Zhang, I will share my memories of
him.
1 China to USA
By the recommendations of Prof. Ding, Shihsun (an algebrais
t, Presi-dent of Peking University) and Prof. Deng, D.G. (Chairman of
Department of Mathematics, Peking University), Mr. Zhang was admitted to
Purdue University as a graduate student in Jan, 1985. Prof. Ding, Shihsun
specifically requested me to take care of Mr. Zhang. When he arrived
, we had a cordial talk. Yitang expressed his desire to work in the field of
Algebraic Geometry. I nodded while remembering the call of French
mathematician Jean Dieudonn ́e in the international conference at
Purdue (
it was to celebrate Louis de Brangles’ result on Bieberbach’s conjecture).
Dieudonn ́e said
“ You should go to the field of algebraic geometry
−that is the future of mathematics” to several hundred analysts.
Yitang also mentioned that he wanted to study under my guidance. Knowing
that he had one published
paper, and some training in the field of Analytic Number Theory under Prof.
Pan (especially in the multiplicative branch, where the central problem is
the twin prime conjecture), I was happy to have a talented student. I was
surprised by Yitang’s next request of working on the Jacobia
n conjecture as his thesis topic. I felt it was odd to select such a
difficult task. After seeing his enthusiasm, I settled on it and did my best
to guide him.I thought Yitang as an ambitious, intelligent, and hard-
working young man.
1
Mathematics Department, Purdue University
1
2 Education at Purdue
After we settled on his thesis topic, we met almost daily for a whole
semester. Our discussions centered on my published paper On the Jacobian
conjecture and the configuration of roots.
J. fur die Reine and angewandte Mathematik, 340, 1983, pp. 140-212
Sometimes, they lasted into the dawn. That was the essential
part of Yi-tang’s first semester at Purdue.For the next two semesters, I
organized a seminar with five graduate
students (including Yitang) on Prof. Hironaka’s monumental papers on the
theory of resolutions of singularities. I believed that we doubled the world
population of those who had studied the papers after we finished two
semesters. Prof. Grothendick once described those papers as among the most
complicated thesises in the human history.
Upon completing three semesters of intensive work, I felt that I might not
have done the right thing (I behaved too much like a modern day “tiger
mother”); I should give him the space to grow. I then laid back and did not
do any pushing. He would come to me once a week to talk, and I listened
carefully. Yitang spent all of his free time thinki
ng of mathematics.
After years, Yitang started to believe that he might have gotten a solution
to the Jacobian conjecture. As a gatekeeper of the palace of the Jacobian
conjecture, I did my duty of examining every claim presented to me, and
denied the entrance of anybody (including myself) if the pro
of was invalid. “Maybe the Jacobian conjecture is a problem for the future
”,I thought. In the year of 1991, his 7-th year at Purdue, Yitang composed
his Ph.D. thesis “Jacobian Conjecture and the Degree of Field Exten
sion”. He presented it to the committee which consisted of myself as the
chair, L. de Brangles, J. Lipman and W. Heinzer. His thesis passed the
committee with flying colors.
3 Daily life
Some people believe that mathematicians are weird. I think d
ifferently. All the mathematicians I know are quite normal. Yitang was a
normal person for those seven years at Purdue. He was elected the President
of the Chinese Student Club at Purdue University, and he discharged his duty
responsibly and served his community well.
2
Yitang had some background in classical Chinese literature
. Sometimeswe talked about them. I mentioned to him a phrase of Confucius:
“A person who knows a job is no match to a person who likes the job. A
person who likes the job is no match to a person who enjoys the job. ” I
thought that
applied to research very well. He agreed. Sometimes I regreted not fixing
him a job. But really, who could tell?
Maybe it was his destiny to endure and turn out to be great. I indeed got a
job for my first student at the end of 70’s. Later when I mentioned the
episode to my friends, they all laughed and told me that it was only the
norm of the long-gone 60’s. Time changed at late 70’s, there was the new
term “tenure track,” and students should look for jobs on their own. So
after Yitang graduated, I told him the normal way of seeking jobs. When I
looked
into his eyes, I found a disturbing soul, a burning bush, an explorer who
wanted to reach the north pole, a mountaineer who determined to scale Mt.
Everest, and a traveler who would brave thunders and lightnings to reach
his destination. Yitang never came back to me requesting rec
ommendation letters. Apparently he did not seek a job. Even to this date, I
do not know what was the best for him, though I was sure of one thing
−
he could not survive the process of “tenure-track,” “tenure,” and “
promotions”. I regarded him as a free spirit, and I should let him fly.
Yitang fl
ew away after he told me that he was going to Rutgers University to talk to
Prof.Iwaniec. I bade him good luck. That was almost 22 years ago. As for
Prof. Ding, Shihsun, I revisited China in 2000. Prof. Ding, then a Vice
−Chairman of the People’s Congress of China, kindly entertai
ned me with a banquet, we talked cordially and enjoyed the moment. | k******0
发帖数: 1073 | 2 http://www.mysanco.com/wenda/index.php?
class=discuss&action=question_item&questionid=3640
【张益唐的博士导师莫宗坚】
张益唐在美国的导师是从台大走出去的代数专家莫宗坚（Tzuong-Tsieng Moh），他
1969年到的普渡大学开始学术生涯。北京大学数学丛书里面的莫宗坚的《代数学》（上
、下）是很不错的代数参考书。莫老师也是性情中人，网上流传的他的《少年游–我的
大学时代》很精彩；看看小标题就能体会到：“读书记 ；生活记；恋爱记；跷课记...
"。文章开头一段：“民国四十七年（一九五八年）我从中部的台中一中考上了台大化
学系。 当我只身远赴台大报到入学时，看到堂堂学府，几排高大的椰子树，眼睛为之
一亮。 又有梳着清汤挂面头发的女生们奔走在校内路上，真是一个新奇的世界！”就
颇为雷人。中间追女生段的开头“经过了一、二年的苦读，我才发现女同学们脸若春花
，眸若点漆。 有些小和尚们，经也不念，钟也不打：「不拜佛祖，只拜观音。」王俊
明坦言：「不论"追"不"追"女生，总要花同样的时间想女生。」”也算实话实说的经典。
张益唐的博士题目是雅可比猜想(Jacobian conjecture)；这一猜想1939年由德国数学
家Ott-Heinrich Keller（1906-1990）于1939年提出来的，是关于多个变量的多项式里
面的一个猜想。这个猜想本身很有名，但更有名经常会产生错误的证明。莫教授在普渡
大学自己的网页上就挂了两篇短文章，一个是说Kuo-Parusinski-Paunescu的雅可比猜
想证明是错的，另一篇是说中国科大的苏育才的证明也是错的；这两篇纠错的文章七、
八年前就上网了。
张益唐也曾牺牲在雅可比猜想上，并且比较惨重。他90年代博士毕业前夕，他宣称解决
了雅可比猜想，并且有几个专家对他的证明很感兴趣。但是，不幸的是他的证明里的一
个引理是其导师莫宗坚的一篇发表的成果，本以为是对的，但再排查时，查出莫教授之
前的结果是错的。你应该知道后果很严重吧？张益唐几年的主要心血付之东流了！！
如果雅可比猜想那时被张益唐攻克了，他应该毫不费劲地可以拿下数学界最高的菲尔兹
奖，因为这个问题太有名，并且他那时候才三十几岁，低于菲尔兹奖得奖的上线岁数40
。 可是这只是虚拟语气了。想当年，当年的天才约翰-纳什作出了著名的纳什嵌入定理
(Nash embedding theorem)也在翘望菲尔兹奖，结果未能如愿，导致精神失常。好在三
、四十年后，诺贝尔奖委员会根据他研究生博士论文建立的纳什均衡理论给了他一个经
济奖，才横扫了失去菲尔兹的阴霾。
虽然未能全部解决雅可比猜想，张益唐对这个问题的部分解决还是有些贡献的，所以他
还是于1991年拿到了普渡大学的博士学位。可是，因为博士论文的结果没有正式发表，
加上和导师的关系极不融洽，张益唐变成博士到手失业开始，连个博士后都没有找到。
对张益唐在普渡的八年，他的博士导师莫宗坚在张益唐出名后的10天内，写了一篇文章
：“张益唐1985年一月至1991年12月在普渡的岁月”,描述了张益唐那几年的学习和工
作。文中说：有时我很后悔没有帮他找工作（Sometimes I regrete not fixing
him a job）； 他从此再也没有找我写过推荐信（He never came back to me
requesting recommendation letters）。在这篇文章中，莫教授还说张益唐是一个有
生活情趣的人，曾经被选为普渡大学中国留学生协会主席，并且干得不错；他也认为张
益唐的古典文学修养很好。
一面要继续做数学，一面还要糊口。毕业后的前6、7年他干过很多杂活，包括零时会计
、餐馆帮手、送外卖。你能想象一代北大数学才子、数学博士好几年送披萨饼、在KFC
卖炸鸡的情形吗？看到这里，你是否对孟亚圣的“天将降大任于是人也，必先苦其心志
，劳其筋骨”有个更深刻的理解呢？
张益唐毕业后基本隐居起来，很少和人来往；他和同学们的联系方式之一就是同学生日
时电邮一个生日问候。他居然能记住班上所有同学的生日，这可能是我们这些凡人做不
到的。那时他的一些同学已经在美国大学里拿到助理教授、副教授甚至正教授的位置；
比如同班同学沈捷、陈敏夫妇已经在宾州州立大学有正式教职。张前几年每年会找这两
口子吃顿饭，基本是悄悄地来，悄悄地走，一年之间基本杳无音讯。 | k******0
发帖数: 1073 | 3 摘要：
张益唐也曾牺牲在雅可比猜想上，并且比较惨重。他90年代博士毕业前夕，他宣称解决
了雅可比猜想，并且有几个专家对他的证明很感兴趣。但是，不幸的是他的证明里的一
个引理是其导师莫宗坚的一篇发表的成果，本以为是对的，但再排查时，查出莫教授之
前的结果是错的。你应该知道后果很严重吧？张益唐几年的主要心血付之东流了！
虽然未能全部解决雅可比猜想，张益唐对这个问题的部分解决还是有些贡献的，所以他
还是于1991年拿到了普渡大学的博士学位。可是，因为博士论文的结果没有正式发表，
加上和导师的关系极不融洽，张益唐变成博士到手失业开始，连个博士后都没有找到。 | W***o
发帖数: 6519 | 4 张的老板听起来挺一般正常的
【在 k******0 的大作中提到】
: Zhang, Yitang’s life at Purdue
: (Jan. 1985-Dec, 1991)
: T.T.Moh
: 1
: Dr. Zhang Yitang made a major advancement to the twin prime conjec-ture as
: verified by Prof. H. Iwaniec, a famous number theorist. Some people are
: curious about Yitang’s life as a graduate student at Purdue University.As
: the thesis adviser of Dr. Zhang, I will share my memories of
: him.
: 1 China to USA
| k******0
发帖数: 1073 | 5 我倒觉得张的老板急着撇清自己，否则不会学生毕业就断了通讯，从不过问一声。
张就是硬气不求老板的推荐信。现在他的丑丢大了。
【在 W***o 的大作中提到】
: 张的老板听起来挺一般正常的
| P*A
发帖数: 7996 | 6 搁生物口，确实挺一般正常的
【在 W***o 的大作中提到】
: 张的老板听起来挺一般正常的
| b*******n
发帖数: 8420 | 7 因为自己的研究结果导致老板之前的错误结论被人发现、名誉扫地，连自己的博士论文
都发布出来，还能指望着老板给写出positive的推荐信？
【在 k******0 的大作中提到】
: 我倒觉得张的老板急着撇清自己，否则不会学生毕业就断了通讯，从不过问一声。
: 张就是硬气不求老板的推荐信。现在他的丑丢大了。
| W***o
发帖数: 6519 | 8 听着怎么这么像FAQ的遭遇
【在 b*******n 的大作中提到】
: 因为自己的研究结果导致老板之前的错误结论被人发现、名誉扫地，连自己的博士论文
: 都发布出来，还能指望着老板给写出positive的推荐信？
| f*******2
发帖数: 410 | 9 的确啊
【在 W***o 的大作中提到】
: 听着怎么这么像FAQ的遭遇
| B****i
发帖数: 466 | 10 老板觉得张不是走"tenure track" 的料。 到今天都不会推荐的。 |
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