On October 22, 2023, Yang Le, an academician of the Chinese Academy of Sciences, passed away in Beijing at the age of 83. People's Vision/Courtesy photo
In 1981, the Chinese Academy of Sciences held a meeting of the members of the Academy, and Hu Keshi, then deputy secretary of the party group of the Chinese Academy of Sciences, reported to Deng Xiaoping. Deng Xiaoping specifically asked: "Are there any people under the age of 50?" and there are no people under the age of 40?" Hu Keshi said, and the youngest is Yang Le, 41 years old.
From his name appearing on the front page of "People's Daily" in 1977, becoming a national idol overnight, to becoming the youngest academician, Yang Le's life curtain really opened. In the following 40 years, Yang Le completed the transformation from a "mathematics star" to a manager, and became one of the leaders of the Chinese mathematics community.
Yau Chengtong, the first Chinese winner of the Fields Medal, said that if he chooses a career, Yang Le will have a chance, "but he does not seek fame and fortune, and feels that the future of mathematics in China is more important than anything else." His selflessness is admirable, and he has made great contributions to the development of mathematics in China." Yau Chengtong said: "He deserves the four words 'unparalleled national warriors'!"
On October 22, 2023, Yang Le passed away in Beijing at the age of 83. The Academy of Mathematics and Systems Science of the Chinese Academy of Sciences wrote in its obituary, "Yang Le is a leader in the Chinese mathematical community and a model of the times. ”
"No degree", make "world-class level"
Yang Le has loved math since he was in junior high school. When I was in high school, coinciding with the implementation of the national "First Five-Year Plan", in response to the call of "concentrating on industrialization", many young people chose to study Xi engineering, "the Department of Electrical Engineering of Tsinghua University is recognized as the most ideal department and major."
This made Yang Le feel conflicted, but he felt that he was still "more interested in mathematics". In 1956, Yang Le was admitted to the Department of Mathematics and Mechanics of Peking University, and six years later, he and his classmate Zhang Guanghou were admitted to Xiong Qinglai's graduate school at the Institute of Mathematics of the Chinese Academy of Sciences. Xiong Qinglai is a veteran figure in the Chinese mathematics community, and mathematicians Chern Shiingshen and Hua Luogeng, and physicist Qian Sanqiang are all his students.
While studying in graduate school at the Institute of Mathematics, Yang Le showed a talent for academics. When he was in college, Yang Le's research direction was to focus on generalized analytic functions in function theory, and after entering the Institute of Mathematics, Yang Le nominally majored in function theory, and his specific direction was determined to be the theory of function value distribution. According to the training model of the Institute of Mathematics, graduate students are equivalent to junior researchers, and they can carry out academic research while learning Xi. Two years after joining the Institute of Mathematics, Yang Le began to publish articles in 1964.
"At that time, there was almost no communication between the domestic academic community and the international community, and we did not notice the latest developments internationally. Yang Le said that under the guidance of Xiong Lao, through the in-depth study of French classical theories, they quickly approached the forefront of research work and reached the international advanced level.
In January 1965, Yang Le and Zhang Guanghou completed their paper "Research on the Regular Rule of Analytic Function Families with Heavy Values I: A New Law and Application" in French, and in September of the same year, Science China published the paper.
If you want to trace Yang's academic path, this paper he co-authored with Zhang Guanghou may be a good start: since then, their research has begun to be internationally recognized.
Yang Le recalled that shortly after the article was published, the "Cultural Revolution" broke out, and all academic activities came to a halt. It was not until 1971, when the policy of the Chinese Academy of Sciences was loosened, that they had the opportunity to consult the literature.
In the library, Yang and Zhang Guanghou discovered that in 1969, an American scholar cited an article co-authored by the two men and a paper published by Yang Le in 1964 in his doctoral dissertation. The scholar's paper was published in a very prestigious international mathematical journal.
In his paper, the American scholar noted that the work of Yang and Zhang "solved an unsolved problem that was raised by the British mathematician Walter Hayman at the International Conference on Function Theory in London in 1964." But because of the lack of academic exchange, the two men didn't even know what the question was raised by Watt at the time.
In the summer of 1965, Xiong Qinglai felt that the students had completed their studies and done relatively good research work, and could graduate early. To this end, he wrote a formal report to the Institute of Mathematics, but the story was not completed.
"In this way, it dragged on until 1966, when the 'Cultural Revolution' broke out, and it didn't matter if I graduated. Yang Le said that sometimes, on some occasions or in more formal media, he will be referred to as a master's degree, "which seems to have a bit of a taste of lifting." In fact, he and Zhang Guanghou studied at Peking University for six years and the Institute of Mathematics of the Chinese Academy of Sciences for four years, but they did not have any degrees.
"Of course, I never asked for corrections or explanations, but I just felt a little inexplicable, which showed that I didn't know the history of the time at all, and it was a bit of a snake and not serious enough. Yang Le explained.
During the Cultural Revolution, the position of the Institute of Mathematics was slightly awkward. "As long as exercise comes, I want to go to the math institute first. Yang Le speculated that this may have stemmed from the disregard for basic research at the time: "In the eyes of some people, it doesn't matter if the Institute of Mathematics is functioning or not, and it can't be a big deal." Unlike research institutes that undertake national defense tasks or are closely related to economic construction, they have the task of developing cutting-edge products and high technologies, and they need to be as stable as possible. ”
But in May 1976, when the American delegation of pure and applied mathematics visited China, the "embarrassing" institute of mathematics had a place to use.
"In terms of science and technology, cutting-edge research and cutting-edge technology all involve applications, which will inevitably be inextricably linked with military technology, which is more sensitive and not easy to reach an agreement, while basic disciplines are relatively simple. In Yang Le's view, in contrast, mathematics that is "relatively detached" in basic disciplines has become the choice of both parties.
During the U.S. delegation's visit, Yang Le shared four findings in English. He remembers that after the speech, the delegation applauded enthusiastically, saying that his work with Zhang Guanghou was "both deep and new."
After returning to China, the US delegation listed Chen Jingrun's "Goldbach Conjecture" and Yang Le and Zhang Guanghou's "Theory of Function Value Distribution" as world-class in a report.
Historical photographs of mathematician Hua Luogeng (second from right) and students Chen Jingrun (first from right), Yang Le (first from left) and Zhang Guanghou (second from left) are displayed at the Hua Luogeng Memorial Hall in Changzhou. People's Vision/Courtesy photo
The youngest member of the Faculty Committee
In July 1976, the Chinese Academy of Sciences issued a special briefing, which briefly recorded the research of Yang Le and others and the international acclaim. It was an eventful time, and the briefing did not cause much repercussions. But later, someone noticed the briefing, so Xinhua sent someone to the Institute of Mathematics for an interview.
On February 26, 1977, Xinhua News Agency's long report "Yang Le and Zhang Guanghou Obtain Important Results in Studying Function Theory" was published on the front page of People's Daily. On the same day, major newspapers across the country also published this Xinhua News Agency press release on the first page.
A year later, in January 1978, the long-form reportage "Goldbach Conjecture" featuring Chen Jingrun was published in People's Literature. Since then, Yang Le, Zhang Guanghou, and Chen Jingrun have become well-known stars.
Many years later, according to the record of the book "The Vicissitudes of the Sea - An Interview with Yang Le", Yang Le analyzed when looking back on this period of the past that at that time, as the party and the state began to shift the focus of their work to economic construction, the long-term policy towards intellectuals in the past also reached the point where it had to be adjusted. The situation is pressing, but it is difficult to return, and under the dilemma, setting an example and commending intellectuals has become a breakthrough in solving the problem.
As for why there are three people from the Institute of Mathematics, Yang Le feels that this is related to the fact that the Chinese Academy of Sciences is the first institution to thaw academic research activities, and it is also related to the characteristics of mathematics, and he just "happened to be selected".
As early as the end of 1971, the Institute of Mathematics resumed the establishment of the research room before the "Cultural Revolution", "at least theoretically resumed research work"; from July 1972, Zhou Enlai reminded the Chinese Academy of Sciences on different occasions that "we should pay attention to the teaching and scientific research of basic science".
"To engage in mathematical research, the conditions are relatively simple, and there is no need for complex and sophisticated experimental equipment, nor does it require a large research team to cooperate with each other in the research process, mainly the personal thinking and calculus of mathematicians. Yang Le recalled that during the "Cultural Revolution", you could not read books, and at that time, if you read professional books, and still wanted to do research and write papers, you would be criticized for the so-called "fame and family" thinking, which is to take the capitalist road.
"Only Chen Jingrun and a few of us really read books and do research. In Yang Le's view, during the 6 years at Peking University and the 4 years at the Institute of Mathematics, the country still provided a very good environment and spent a lot of financial and material resources to train them under very difficult conditions.
In June 1977, the year after their names appeared on the front page of the People's Daily, Yang Le and Zhang Guanghou were invited to Zurich, Switzerland to participate in academic exchange activities. Yang Le handed over the invitation letter to the Chinese Academy of Sciences, and the Foreign Affairs Bureau of the Chinese Academy of Sciences drafted a report and submitted it to Fang Yi, then president of the Chinese Academy of Sciences. Unexpectedly, this report actually alarmed the Political Bureau of the CPC Central Committee.
"At that time, the top leaders of the central government all circled the report to express their agreement. Yang Le recalled that the academic conference they attended in Zurich in April 1978 was later confirmed to be the first academic activity that a domestic scholar participated in abroad in his personal capacity after June 1966.
In China, many young people have also been influenced by Yang Le, Zhang Guanghou, and Chen Jingrun and embarked on the road of mathematics. In 1978, the Institute of Mathematics resumed enrolling graduate students, with an original enrollment of 27 students, but more than 1,500 students enrolled. In this regard, Yang Le saw it clearly: "Because Chen Jingrun, me and Zhang Guanghou were highlighted by the media at that time, there were many students who applied for our examination, and there was a certain blindness. ”
According to a report by China Science Daily, it was also the year that Qiao Jianyong, former president of Beijing University of Posts and Telecommunications, took the college entrance examination, and his choice was mathematics; when Yuan Yaxiang, an academician of the Chinese Academy of Sciences, went to university, he also chose mathematics.
Li Wenlin, a researcher at the School of Mathematics of the Chinese Academy of Sciences, has worked with Yang Le for many years. He remembered that in that era when he needed a letter of introduction on a business trip, when he went to the hotel with a letter of introduction signed by the mathematics institute, he would be asked by the waiter: "Is it the mathematics institute of Chen Jingrun, Yang Le, and Zhang Guanghou?"
Born in Tianjin in the late 60s of the last century, Sun Guodong is the editor-in-chief of Lawyer's Digest. He remembers that since he was a child, the topic he wrote about the most in composition class was "My Ideal". Catching up with the "Cultural Revolution" in childhood, Sun Guodong, like many boys, had the ideal of "being a member of the People's Liberation Army".
In 1978, Sun Guodong was in the third grade of primary school. "For a time, 'four modernizations' and 'marching towards science' have become hot words on the lips. Sun Guodong recalled, "Today's people may not imagine that there was a period in China when mathematicians became the stars of all eyes and sought after by the whole people." ”
In an interview with Southern Weekly, Sun Guodong said that after hearing about Yang Le and Zhang Guanghou's deeds on the school's radio, the teacher asked everyone to "write a letter to Yang Le and Uncle Zhang Guanghou" in Chinese class. "Writing letters to mathematicians in Chinese class, Yang and Zhang's uncles broke through the boundaries between arts and sciences for the first time. Sun Guodong said that when he wrote again, many students' dreams became mathematicians.
Three years after his name appeared on the front page of the People's Daily, in 1980, Yang Le was co-opted as a member of the Faculty (editor's note: later an academician). Yang Le was the youngest of the school members, and was under the age of 41 when he was elected.
The "sophisticated" side
After becoming famous, in the context of repeatedly emphasizing the rejuvenation of cadres, Yang Le began to hold some administrative positions. At the end of 1982, under the "repeated mobilization" of Lu Qikeng, deputy director of the Institute of Mathematics, Yang Le became the deputy director of the Institute of Mathematics, and later served as the director.
During his tenure as deputy director, he and his director, Wang Yuan, proposed to set up an open research institute and strengthen exchanges with universities and other research institutes. In fact, as early as 1980, when Yang Le and Zhang Guanghou reported their feelings to Qian Sanqiang, then vice president of the Chinese Academy of Sciences, they had their own thoughts on how to run a good research institute. He said: Mathematics departments of foreign universities implement the principle of administering the university by professors, and the administrative staff in the departments are few but capable, with professors as the center, and serve scientific research; secondly, they do not engage in "inbreeding."
In 1986, the Chinese Mathematical Society began to prepare for a general election. As the secretary general of the Mathematical Society at that time, Yang Le proposed a reform plan, the main contents of which are: the newly elected directors must be under the age of 60. The main purpose of the reform is to avoid the aging and stiffness of the leadership of academic organizations and academic monopoly, so that more young and energetic scholars can join in and develop all branches in a balanced manner.
Yang Le recalled that after Wu Wenjun, the chairman of the Mathematics Society at that time and a master mathematician, learned about this, he said very childishly, "If you change it now, you just let us go down." In this regard, Yang Le later explained, "Actually, Mr. Wu is relatively indifferent to fame and fortune, and he doesn't care about what position he holds, and he doesn't care about the title of the chairman." ”
At that time, out of respect for Mr. Wu, Yang Le did not say anything. He promoted the reform at the Fifth General Assembly the following year, at which he held no position.
Around 2010, someone from the Mathematics Society wanted to raise the limit of "the age of newly elected directors cannot exceed 60 years old" to 70 years old, so they specially asked Yang Le's opinion. Yang Le made it clear that he disagreed. He said that in the 80s of the last century, we could all encourage more new forces to participate in academic management, and today, with the rapid development of science and technology, it is not appropriate to consider taking care of the elderly. Later, the proposal fell through.
Lack of money was a pain in the hearts of scientific researchers in that era. Yang Le remembers that until the end of 1998, the highest salary in the mathematics institute was not as good as that of a taxi driver. When holding talks with foreign experts, the Mathematics Society could not afford to rent a special conference room due to financial constraints, so it used the café in the hotel to put together the tables inside.
In 1990, at the end of the first term of the director, Yang Le asked the leaders of the hospital to resign due to "financial constraints, and it was difficult to make a difference", and then he was repeatedly persuaded to stay in office. In January 1995, Yang Le, whose second term expired, resolutely resigned from the post of director despite the retention of the Chinese Academy of Sciences. But in 1998, the Chinese Academy of Sciences integrated the four research institutes originally engaged in mathematics research to establish the Institute of Mathematics and Systems Science, and the 59-year-old Yang Le came out again and became the first dean.
The difficulty of reform is very huge: the innovation base of the School of Mathematics has a strict quota of personnel, the original four research institutes have 100 administrative staff and 400 scientific researchers, and the number of innovation bases is only 200. In addition, in order to ensure the innovation vitality of the base, the average age is required to not exceed 40 years old. Who enters and who does not enter, touching personal interests, the resistance can be imagined.
An important reason why Yang Le returned to the mountain was that he felt that "some ambitions have not been rewarded." I served two terms as director, and I was unable to make a difference due to funding, so this was an opportunity."
After the reform, the treatment of those who have entered the innovation base has been greatly improved, and the treatment of those who have not entered the base has also been improved, from 1,000 yuan to 3,000 yuan, and they can do scientific research as usual. In order to attract outstanding young people, the monthly salary of the best young academic leaders in the front line in the reform reached 10,000 yuan, while the highest salary of academicians such as Yang Le and Wang Yuan of the Institute of Mathematics in the past was 6,000 yuan.
Yau Chengtong commented that Yang Le is "gentle and pure, and treats people with sincerity". When Zhang Guanghou was dying, he stayed by his bedside all night; when he heard that a scientific researcher who had just returned from abroad was seriously ill and could not be admitted to the ward, he personally went to the hospital to negotiate until the staff promised to solve the problem immediately.
As a mathematician, Yang Le also has a very "WTO" side. Li Wenlin recalled that once, the new building of the School of Mathematics had to install an elevator, but the elevator manufacturer's quotation was relatively high, and a vice president in charge of infrastructure construction could not communicate with the other party. The other party is a Sino-Japanese joint venture, and after Yang Le knew about it, he took a photo of himself and the Japanese crown prince and princess. Relying on this photo, Yang Le got a preferential price as he wished.
Mu Guangfeng was the head of the Secretariat of the State Council's Environmental Protection Commission, and Yang Le's wife, Huang Jiyuan, a college classmate of Yang Le's father Huang Wanli, was his cousin. Mu Guangfeng remembered that during Yang Le's tenure as the director, once, he went to the other party's house as a guest, and when chatting after dinner, the guests kept coming, "some want to evaluate the title, and some want to divide the house, and they all come to him."
At that time, Mu Guangfeng asked Yang Le whether the holding of an administrative position by an expert was a kind of brain drain? Yang Le shrugged his shoulders and said, "There is no way. ”
"It's only natural that a young mathematician like Yang Le, who has both ability and integrity, will be promoted to some leadership positions. Therefore, from the end of the 70s of the 20th century, Yang Le will devote a considerable part of his energy to this (social work). The late Wang Yuan, an academician of the Chinese Academy of Sciences, once wrote, "It is undeniable that social work consumes too much of his (Yang Le's) energy. ”
On July 31, 2022, the 9th World Congress of Chinese Mathematicians (ICCM), co-sponsored by Southeast University and Tsinghua University, was held in Nanjing. People's Vision/Courtesy photo
"We've turned the page"
While taking up an administrative position, Yang Le said that his scientific research work is still "carried out as much as possible".
The function value distribution theory that made Yang Le and Zhang Guanghou famous has a long history, and since the 80s of the 19th century, it has also been the mainstream direction of the development of mathematics. However, Yang Le clearly realized that after half a century of development, the research work in this field has tended to be perfect, and he is "lucky" to be able to make outstanding results.
Therefore, Yang Le felt that it was not appropriate to guide many young students to devote themselves to it, which was one of the reasons why he did not recruit students in the early days. In fact, even if he started recruiting students, Yang Le's principle was to accept fewer students. In the past 40 years of mentoring career, Yang Le has officially recruited only 7 graduate students, plus the postdoctoral students he supervised, a total of about 10.
Yang Le once told the students that the theory of the distribution of functions was only used as a training in their graduate studies, and that "they should move on to other vigorous research fields in the future."
In fact, Yang Le himself has tried to change the direction of his research. Wang Yuan once pointed out in an article that in April 1981, at the University of Science and Technology of China in Hefei, Yang Le made a work report to Hua Luogeng and the teachers and students of the Department of Mathematics of the University of Science and Technology. In addition to the value distribution theory, the report also uses functional analysis, "which shows that Yang Le has made efforts to expand his research field".
At the end of 2002, after Yang Le retired from the position of dean of the School of Mathematics, especially after the age of 70, he basically stopped working in the front line of scientific research. In addition to being limited by the direction of research, it is also related to some young perceptions: Yang Le has met talented seniors, and still insists on publishing papers in his later years, but academically speaking, the old man's papers have lacked novelty.
Yang Le once discussed privately with Zhang Guanghou: "When we are over 60 years old, we should not publish any papers in such a reluctant way." "Know how to advance and retreat, be sure in your heart, be sober and free. "China Science News" once described him in a report.
In the years that followed, a large part of Yang's energy was devoted to the Morningside Mathematics Center of the Chinese Academy of Sciences, which he and Yau founded in 1996. Yau Chengtong serves as the director of the academic committee, and Yang Le is the deputy director. After experiencing the era of isolation, Yang Le is well aware of the importance of international academic exchanges, and the Morningside Mathematics Center has undertaken the important task of academic exchanges at home and abroad to a large extent.
Yau once said in an interview with the media that they wanted to make the center an institution like the Institute of Mathematical Sciences at the Institute for Advanced Study in Princeton, but at that time China was still relatively isolated, and "it took a lot of work": on the one hand, to persuade mathematicians from abroad, and on the other hand, to persuade other institutions in China to send young people to study Xi.
Yau Chengtong said that he had a lot of ideas, but at that time he was not in China for a long time, and the main person who completed it was Yang Le, "I encountered a lot of difficulties in the middle", but Yang Le "was really brave and survived".
In an interview with Southern Weekly, Li Wenlin said: "He (Yang Le) has a clear sense of historical responsibility, which is to promote the development of Chinese mathematics. ”
After Yang Le's death, Li Wenlin recalled on many occasions that the two had met before. It was the autumn and winter of 2019, Li Wenlin came out of the School of Mathematics and walked home, and met Yang Le, who also came out of the office. The two chatted while walking, and when they reached the intersection to separate, Yang Le turned around and said to him, "Our page has been turned." ”
(Reference book: "Idol" Mathematician Yang Le: Half a Century of Advance and Retreat)
Southern Weekly reporter Li Gui
Editor-in-charge: Qian Haoping