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Yitang Zhang
USINFO | 2013-11-19 13:48
| Yitang Zhang（"Tom" Zhang） | |
| Born | 1955 (age 57–58) |
| Residence | United States |
| Nationality | United States |
| Fields | Mathematics |
| Institutions | University of New Hampshire |
| Alma mater |
Purdue University Peking University |
| Thesis | The Jacobian Conjecture And The Degree Of Field Extension (1992) |
| Doctoral advisor | Tzuong-Tsieng Moh |
| Known for | Work with twin primes |
Yitang "Tom" Zhang (Romanized form: Yitang Zhang, Chinese:, Zhāng Yìtáng) is a Chinese-American mathematician working in the area of number theory.
On April 17, 2013, Zhang announced a proof that there are infinitely many pairs of prime numbers which differ by 70 million or less. This proof is the first to establish the existence of a finite bound for prime gaps, resolving a weak form of the twin prime conjecture. Zhang's paper was accepted by Annals of Mathematics in early May 2013. The proof was refereed by leading experts in analytic number theory.
If we let P(N) stand for the proposition that an infinitude of prime pairs differ by exactly N, then Zhang's result is equivalent to the statement that there exists at least one even integer k < 70,000,000 such that P(k). The classical form of the twin prime conjecture is equivalent to P(2); and in fact it has been conjectured that P(k) for all even integers k. While these stronger conjectures remain unproven, subsequent refinements of Zhang's technique claim to have proven that P(k) for some k ≤ 4680.
Education
Zhang entered Peking University in 1978 as an undergraduate student and received his B.Sc. degree in mathematics in 1982. He became a graduate student of Professor Pan Chengbiao, a number theorist at Peking University, and obtained his M.Sc. degree in mathematics in 1985. Several articles (in Chinese) by his former classmates have all confirmed that Zhang was a top student among his peers. After receiving his master's degree in mathematics, with recommendations from Professor Ding Shisun, President of Peking University and Professor Deng Donggao, Chair of the Math Department of Peking University, Zhang was granted a full scholarship by Purdue University, where he arrived in January 1985 and studied for seven years. He obtained his Ph.D. in mathematics from Purdue in December 1991.
Career
Zhang's Ph.D. work was on the Jacobian conjecture. He originally thought he had solved the problem until a lemma he cited from his advisor Tzuong-Tsieng Moh's previous paper was found to be wrong. After graduation, Zhang had a hard time finding an academic position. In a recent article, Zhang's thesis advisor, Professor Tzuong-Tsieng Moh, recalled that "Sometimes I regretted not fixing him a job" and "He never came back to me requesting recommendation letters." He managed to find a position as a lecturer after many years. He is still currently a lecturer at the University of New Hampshire, where he was hired by Kenneth Appel back in 1999. Prior to getting back to academia, he worked for several years as an accountant and a delivery worker for a New York City restaurant. He also worked in a motel in Kentucky and in a Subway sandwich shop.
