On May 20, the farewell ceremony of Wang Yuan, a famous mathematician and academician of the Chinese Academy of Sciences, was held at the Babaoshan Funeral Home. A number of scholars with white sideburns came to the scene on crutches and sent the "elders" on their last journey.
Sixty-four years ago, 27-year-old Wang Yuan proved the Goldbach conjecture proposition "2+3", putting Chinese scholars at the forefront of research on this world-famous mathematical problem for the first time, a pioneering work that profoundly influenced the follow-up research of Pan Chengdong and Chen Jingrun. Influenced by his teacher Hua Luogeng, Wang Yuan also put forward the requirements of "aiming at original and challenging work" for his juniors. But in life, Wang Yuan is indifferent to fame and fortune, and he hides himself behind his achievements.
The farewell ceremony of Mathematician and Academician of the Chinese Academy of Sciences Wang Yuan was held at the Babaoshan Funeral Home. His colleagues and students went to the scene to mourn. Beijing News reporter Zhang Lu photographed
"Cut off" literary hobbies, specializing in mathematics
In 1930, Wang Yuan was born into a family of intellectuals in Lanxi, Zhejiang. After the outbreak of the War of Resistance Against Japan, due to frequent family relocations, his father took the time to teach him Chinese and arithmetic during the bumpy journey. It was not until 1940 that Wang Yuan began to formally enter primary school.
When he was a child, Wang Yuan did not show outstanding mathematical talent, and he accepted a new mathematical concept even more slowly than others. He is not willing to blindly memorize and set formulas by rote, but to find out the reasoning and break the casserole to ask the end.
In an article reminiscing about his college career, Wang Yuan admitted that he did not study well in the last two years of high school and watched a lot of movies, so he was only admitted to Yingshi University in Zhejiang Province. Fortunately, his college was soon merged into Zhejiang University, and analyst Chen Jiangong and geometrist Su Buqing both taught in the department of mathematics. To be able to enter such a collective, Wang Yuan strongly hopes to rely on his own struggle to change his appearance. He "cut off" his literary and artistic hobbies such as calligraphy, painting, music, etc., and specialized in mathematics. In college, Wang Yuan experienced the rigor of mathematics for the first time, and also developed an interest and confidence in mathematics.
In 1952, Wang Yuan graduated from the Department of Mathematics of Zhejiang University, and because of his excellent grades, he was recommended by Chen Jiangong and Su Buqing to work at the Institute of Mathematics of the Chinese Academy of Sciences in Beijing. Before leaving Zhejiang University, Chen Jiangong said to him with a heavy heart: "You are the 'daughter' we married, learn from Hua Luogeng, he is the best mathematician in China." ”
The fledgling Wang Yuan soon attracted the attention of Hua Luogeng. "He talked to me individually and asked me to do number theory." Wang Yuan once recalled that at that time, the number theory group had two seminars, one was the number theory introduction seminar, and the other was the Goldbach conjecture seminar.
Challenged with mathematical puzzles, the hand-cranked computer is shaken
Goldbach's conjecture research is the most brilliant chapter in Wang Yuan's mathematical career.
In 1742, Goldbach proposed the Goldbach conjecture in a letter to the mathematician Euler (the common conjecture today is stated as Euler's version, i.e., any even number greater than 2 can be written as the sum of two prime numbers), but neither of them could prove it. For 200 years, this conundrum has attracted the attention of mathematicians around the world.
In 1952, at the age of 22, Wang Yuan challenged this mathematical puzzle. At that time, goldbach conjecture was best recorded internationally as "4+4", which was made by the Soviet scientist Bukhsitab in 1940.
Recalling the years of tackling key problems, Wang Yuan once said that he was full of energy at that time, and as long as he took a nap at noon, he did not have to sleep all night. Since the dormitory and office were in one place, he rested for an hour or two when he was tired and got up to continue working. At that time, there were no computers in China, and the only hand-cranked computer in the Institute of Mathematics was "contracted" by him alone until it was shaken. Wang Yuan had accumulated fatigue and illness, but his health improved slightly, so he continued to study day and night.
After two years of hard work, Wang Yuan "got nothing", and he was once discouraged, suspecting that he did not have the talent to study the Goldbach conjecture, and it was better to do some work within his ability. At this time, a Polish scientist visited China, Wang Yuan improved his article, and the article on number theory functions was published in Poland. "China's own young people were able to cooperate with foreign mathematicians to publish papers, which was a big deal at the time, and the media reported on it at great length." Wang Yuan shook his determination to study the Goldbach conjecture and decided to continue to research in the direction of the paper.
Seeing that Wang Yuan had retreated, Hua Luogeng said in one sentence: "It is not very important for you to do these problems, it is not a central problem, you must insist on doing goldbach conjecture." After being "awakened" by his teacher, Wang Yuan reinvigorated and used the sieve method in analytic number theory for the study of the Goldbach conjecture, and finally proved the proposition "3+4" in 1955. "At that time, Hua Lao was very happy, because it left a trace in history, although it was still far from proving 1+1, but it took a step forward."
Hua Luogeng and Wang Yuan. /Official website of the Academy of Mathematics and Systems Science, Chinese Academy of Sciences
In 1957, Wang Yuan took a step closer and proved "2 +3", which means that each sufficiently large even number can be expressed as the product of up to two prime numbers plus the product of up to three prime numbers. This is the first time that Chinese scholars have leapt to the world's leading position in this field of research. At this time, Wang Yuan was only 27 years old. His pioneering work profoundly influenced the follow-up research of Pan Chengdong and Chen Jingrun.
In 1966, after making new and important improvements to the screening method, Chen Jingrun proved "1 + 2", known as "Chen's theorem".
He opened up new areas of research and wrote a biography for Hua Luogeng
In the late 1950s, Wang Yuan gradually faded away from the goldbach conjecture and began to focus on other fields. He worked with Hua Luogeng on the application of number theory in approximation analysis. According to Wang Yuan's recollection, opening up a new research direction means that the knowledge and experience familiar to the past are basically useless. But he still decided to open up a new path and gradually deepen the study of the problem little by little.
The theorem proved by the duo in 1973 is known as the "Hua-Wang method". In the late 1970s, Wang Yuan systematically summarized the achievements in this regard, which had a wide international impact. Number theory was considered by the British mathematician Hardy to be the purest and most useless field of mathematics, and Wang Yuan's research in collaboration with others opened up a new world of number theory applications.
After passing more than half a hundred years, Wang Yuan regained his literary hobby and spent 10 years writing a biography for his teacher, "Hua Luogeng". Writing biographies is a completely unfamiliar field for a mathematician, and in order to truthfully reproduce Hua Luogeng's experience and explain the social and historical background of the time, Wang Yuan collected as many historical materials as possible and repeatedly verified them. After the book was published in 1995, it was also translated into English by the internationally renowned Springer Publishing House and published overseas.
Li Wenlin, former deputy director of the Institute of Mathematics of the Chinese Academy of Sciences, is Wang Yuan's student and colleague. He said that in the biography of Hua Luogeng, Wang Yuan focused on Hua Lao's outstanding contributions to mathematics and his personality charm, but the book also mentioned the imperfect aspects of Hua Lao. "A person always has two sides, and writing about a person can't just write good words. It is precisely because he wrote in this way that the reader will feel the real, intimate and respected Hua Lao from the book. For Li Wenlin and other authors who wrote biographies for Wang Yuan, Wang Yuan always asked them to write about his shortcomings.
In recent years, Wang Yuan, who is old, is still doing the work of computational number theory and working for the development of the institute. Because of his deep qualifications and great contributions, he was affectionately called "Elder" by his colleagues. It is often seen that the thin "elders" stagger toward the school's own office.
Feng Keqin, a retired professor at Tsinghua University, and Sun Shuling, a retired professor at the University of Chinese Academy of Sciences, have taught Wang Yuan's classes. On the day of the farewell ceremony, two octogenarians came together to bid farewell to the teacher. This parting evoked many memories of their time with the teacher. Feng Keqin said that in his later years, Wang Yuan asked him to cooperate in translating a foreign collection of essays on numeracy theory. "Elder Wang translated the first ten pieces, and it took him five or six years to write the manuscript by hand." Feng Keqin said, "This may be the last book he translated, in fact he still wants to do a lot of work, but because of physical reasons, he has not finished it." ”
Educate the younger generations and aim for original work
In terms of educating people, Wang Yuan also has his own set of logic. He once said that the pursuit of 100 points is not interesting, and curiosity should be there from an early age. "My teaching philosophy is to let students do it, including finding directions and finding topics. It doesn't matter if I don't understand what you do, I'll learn from you. ”
Mathematician Zhang Shouwu is a student of Wang Yuan, and Tian Ye, a researcher at the Academy of Mathematics and Systems Science of the Chinese Academy of Sciences, studied under Zhang Shouwu and is a student of Wang Yuan's students. He clearly remembers a scene in 2006 when he returned to China from Columbia University to work, he was called to the office by Wang Yuan. Wang Yuan showed him a piece of paper that recorded Wang Yuan's achievements in life. He hopes that we, the younger generations, will work hard, aim at original, challenging work, not be impetuous, and immerse ourselves in learning." Hopefully, after more than ten years of hard work, I can have the same piece of paper. ”
Tian Ye said that the office building where the two were located was next to each other, and Wang Yuan often gave him business guidance. "He has extremely high requirements for business, and once said that our unit will enter people in the future, and can only enter the people with the highest academic level." When he usually talks about mathematics, he only talks about the most essential parts of mathematics. A person may do dozens of tasks in his lifetime, but there may be only a few jobs that are really important or can be passed on to the world, and he attaches great importance to this kind of work. ”
In the eyes of his nephew Guo Dahai, his uncle Wang Yuan has a subtle influence on the family. "There was a great scientist in the family who set an example for the children from an early age." He recalled that when he was 13 years old, he participated in the national mathematical competition, won a good ranking, and was selected by the junior class of the University of Science and Technology of China. "At that time, the national media was reporting on the junior class, and it was a very honorable thing to enter the junior class. But when I went to my uncle for consultation, he advised me not to take shortcuts and to take it step by step.
Later, Guo Dahai took the middle school entrance examination and college entrance examination step by step, entered the Chinese Academy of Sciences to study and studied abroad. The "no shortcut" attitude towards life has been influencing him.
Indifferent to fame and fortune, rejecting favorable conditions abroad
Indifferent to fame and fortune is the most evaluation given to Wang Yuan by family, colleagues and students.
"Disciple Sun" Tian Ye said that Wang Yuan is very modest, but everyone who studies mathematics knows that the pioneering nature of his work has played a crucial role in the development of Chinese analytic number theory, but he never mentioned it. Feng Keqin said that Goldbach guessed that the first batch of results was made by Wang Yuan, but he has been pushing Chen Jingrun's credit and never talking about his own achievements, which makes the students very admirable.
As for his own statement that "shrouded in the aura of Hua Luogeng and Chen Jingrun", Wang Yuan once said that he did not care. He said that Hua Lao had an influence on a generation of mathematicians and was a great mathematician in China. Chen Jingrun has been doing mathematics with a low-grade fever for decades, which is very remarkable.
"Wang Yuan is a typical intellectual, he is conscientious in his studies, and does not pursue fame and fortune." Feng Keqin sighed that after Wang Yuan retired, some units wanted to give him a nominal position, but he politely refused. He was one of the first academicians to propose "retirement" and was also a member of the Chinese People's Political Consultative Conference who took the initiative to propose not to be re-elected.
Guo Dahai said that his uncle's generation, under the extreme material poverty at that time, dedicated all their wisdom and youth to the country. In the 1980s, my uncle was invited abroad by American universities to give lectures and lectures, and promised to let him take the position of senior researcher, give him a green card, and offer favorable conditions that were far from those in China, but Wang Yuan refused. "I asked him why, and he said he was just an ordinary person, not a genius, at most a talent. As he spoke, he stood up, pointed to the mosquito net rod in the room near the ceiling, and said, The state has given me such a high honor and status, I am satisfied that I can make some contribution to the country. ”
Yang Shasha, a retired office of the Academy of Mathematics and Systems Science of the Chinese Academy of Sciences, once helped take care of Wang Yuan's life, accompanying him to the hospital to see a doctor and participate in activities. "He was a kind old man with a good reputation. Elder Wang usually tries not to cause trouble to others, he has never asked me, and he will not look for me easily. ”
In his later years, Wang Yuan studied under Ouyang Zhongshi and immersed himself in calligraphy. He believes that the aesthetics of mathematics and calligraphy have a high degree of consistency, and the common standard of both is the beauty of the line, and the simplicity and truth are beautiful. Zhu Ruzhang, a retired cadre of the Institute of Software of the Chinese Academy of Sciences, is one of the initiators of the "Collection of Science, Culture and Art", and in his impression, Wang Yuan is low-key and gentle. "Among the academicians, Wang Yuan's calligraphy is very good, people have no shelves, and when someone asks him for a banner, he writes it to others."
On May 14 this year, Wang Yuan died of illness in Beijing. At the age of 91, he completed his mathematical life, but like the teacher Hua Luogeng hoped, his mathematical contributions have left traces in history forever.
Beijing News reporter Zhang Lu intern Wang Jingxi
Edited by Zhang Lei, Proofread by Liu Baoqing
Source: Beijing News