Cai Tianxin Photography Chen Yuxiao
Cover news reporter Zhang Jie intern Li Xinyue
Two Sichuanese in Hangzhou: the Northern Song Dynasty Su Dongpo (1037-1101) left dikes and poems, and the Southern Song Dynasty Qin Jiushao (1202-1261) left bridges and books.
Bashu Land, Zhong Lingyu Xiu. The land has nurtured many brilliant cultural celebrities, including the famous Southern Song Dynasty mathematician Qin Jiushao, who was born in Puzhou (present-day Anyue County, Ziyang City), and is one of them. Qin Jiushao, along with his contemporaries Li Ye, Yang Hui and Zhu Shijie, was known as the "Four Great Mathematicians of the Song and Yuan Dynasties", and george Sutton, the "father of the history of science", believed that "Qin Jiushao was one of the greatest mathematicians of his people, his time, and indeed of all times." Qin Jiushao studied astrology, rhythm, arithmetic, and construction, and wrote the "Nine Chapters of the Book of Numbers", known as the "Treasure Book of Arithmetic", which represented the advanced level of Chinese mathematics at that time and occupied a lofty position in the history of world mathematics. In 1842, the Nine Chapters of the Book of Numbers was first printed and published after being edited by the famous arithmetic song Jingchang, ending nearly 600 years of copying history. Previously, it was successively included in the Yongle Canon of the Yuan Dynasty and the Siku Quanshu of the Ming Dynasty. As an important part of China's excellent traditional culture, Qin Jiushao's mathematical ideas are also worthy of our careful study, study and inheritance today.
Lecture by professor of mathematics and poet
It has both the style of literature and the rigor of reason
At 7:30 p.m. on October 18, Cai Tianxin, a professor of mathematics, writer and traveler at Zhejiang University, was a guest of the "Hall of Fame" and gave a lecture at the Sichuan Provincial Library with the theme of "Qin Jiushao, Daoguqiao and China's Remaining Theorems". Behind Qin Jiushao, the great mathematician, what kind of growth experience is hidden, and what is the important value and significance of his knowledge for today and future generations? What is the unique charm of ancient Oriental mathematics? Mr. Cai Tianxin is a professor, doctoral supervisor and Qiushi Distinguished Scholar of the School of Mathematics of Zhejiang University, who has won the National Science and Technology Award and the National Teaching Achievement Award, has traveled to more than 100 countries, and has published more than 30 literary, academic and popular science works. At the Lecture Hall of Fame, Professor Cai and Qin Jiushao conducted a dialogue across time and space to reveal the answers to the questions for readers one by one.
Before talking about Qin Jiushao, a Sichuanese from the Southern Song Dynasty, Cai Tianxin first mentioned Su Dongpo, a Sichuanese from the Northern Song Dynasty, "They are all Sichuanese, and they have all had close ties with Hangzhou. Su Dongpo left a causeway and poems. Qin Jiushao left behind bridges and books. After that, Cai Tianxin respectively described the specific achievements of Chinese mathematics before the Song Dynasty, Song Dynasty mathematics and Qin Jiushao, the influence of Qin Jiushao's mathematics, and clarified and corrected the moral doubts that Qin Jiushao had suffered in history. In the course of his speech, Cai Tianxin quoted from the ancient Chinese mathematical classics such as the Zhou Ji Arithmetic Classic, the Nine Chapters Arithmetic, the Haidao Arithmetic Classic, the Shu Shu Shu, the Sun Tzu Arithmetic Classic, the Zhang Qiu Jian Arithmetic Classic, and the Ji Gu Suan Jing, as well as the mathematical factors in the legend of the Chu-Han rivalry.
Courtesy of Cai Tianxin
While telling the story of ancient mathematics, Cai Tianxin also compares it with current mathematical applications such as "cryptography" and "computer algorithms", helping readers to more clearly understand the value of the achievements of ancient oriental mathematicians like Qin Jiushao. Professor Cai is not only a mathematical genius admitted to the mathematics department of the university at the age of 15, but also a senior writer and poet who has published many poetry collections.
After listening to Professor Cai Tianxin's vivid explanation, the reader has a more comprehensive and in-depth understanding of Qin Jiushao, an outstanding mathematician in ancient China, and more deeply understands the spirit of pursuing truth displayed by Qin Jiushao.
Cover News, SichuanGuan News, Sichuan Observation and other media conducted a live video broadcast of the lecture in the celebrity lecture hall. The lecture that night, in addition to attracting countless math enthusiasts to watch, also gained a lot of heat in the network, according to statistics, [Hall of Fame (27) | What is the charm of ancient oriental mathematics? Zhejiang University professor and poet Cai Tianxin deeply understands Qin Jiushao] Live broadcast, cover news client a total of 1.023 million people watched, cover news Weibo, cover news video Weibo, today's headlines, mobile phone Baidu, cover news video number, vibrato, Kuaishou a total of 367,000 people watched. At the same time, the live broadcast was viewed by 197,600 viewers on the SichuanGuan News live client. In addition, the live broadcast was watched by a total of 171,000 people in Sichuan. According to statistics, a total of more than 1.7586 million netizens watched the live broadcast.
Qin Jiushao's mathematical achievements preceded those of the West by hundreds of years
The "Great Yan Qiu Yi Shu" is one of the main tools of modern cryptography
Before talking about Qin Jiushao, Cai Tianxin first sorted out the achievements of Chinese mathematics before the Song Dynasty, mentioning that the first mathematician worth telling in ancient China was Zhou Gong, "Zhou Gong was the author of Zhou Li and attached great importance to mathematics. Later, there were the Zhou Jie Arithmetic Classics and the Nine Chapters of Arithmetic. Around the 13th century, when the European Middle Ages were coming to an end, the "Four Great Masters of the Song and Yuan Dynasties" appeared in the history of Mathematics in China: Qin Jiushao, Yang Hui, Li Ye, and Zhu Shijie. In the lecture, Cai Tianxin made a discussion of several other mathematicians, focusing on Qin Jiushao's life experience and mathematical achievements.
Qin Jiushao is a great mathematician in history, and Qin Jiushao cannot but understand what very important mathematical work he has done. Mathematics is the brightest jewel in the crown of science, and it is not easy to understand mathematics. As a professor of mathematics, when Cai Tianxin talked about Qin Jiushao, he focused on introducing several very important mathematical achievements of Qin Jiushao to the reader. These include the open square positive and negative technique, the sea wheel formula, the great derivation total number technique, the great yan one technique, and so on.
When talking about the "Great Yan Total Technique", Cai Tianxin mentioned a very noteworthy detail: when the "Great Yan Total Technique" was transmitted to the Ming Dynasty, it was seen by a missionary in China, and he wrote a paper on this result and introduced it to the West. The West named it the "Chinese surplus theorem". In Europe, euler in the 18th century and Gauss in the 19th century each conducted a meticulous study of the congruent group, and also reached the same conclusion as the "Chinese surplus theorem", but more than 500 years later than The Chinese Qin Jiushao.
Why do Westerners refer to Qin Jiushao's "Great Derivation Technique" as the "Chinese Surplus Theorem"? Cai Tianxin explained that on the one hand, this is difficult to pronounce the name of Qin Jiushao in Westerners, and on the other hand, because we did not know much about Qin Jiushao in China later, we called this theorem "Sun Tzu's theorem". In fact, this statement is not scientific, because Sun Tzu only gave an example, it was Qin Jiushao who raised it to an ordinary degree, and gave the answer, this theorem should be called "Qin Jiushao's theorem".
In Cai Tianxin's foreign edition of Modern Introduction to Classical Number Theory (Chinese edition published by Science Press), the "Qin Jiushao Theorem" is fully stated, "This is also the first time in history that the Chinese surplus theorem is directly not called the Chinese surplus theorem in a textbook, it is called the Qin Jiushao theorem." That's the only thing I call it in this book. In the foreign language version of the book, I also specially equipped the original Chinese of Qin Jiushao's "Nine Chapters of Arithmetic", and explained in detail the solution given by Qin Jiushao to this equation and the process of completing the solution. ”
In Cai Tianxin's view, "Qin Jiushao's theorem can be said to be the most world-influential theorem discovered by Chinese, which is indispensable for any basic number theory textbook in China and abroad, and has also been expanded into another branch of mathematics, abstract algebra." It has also been applied to cryptography, the proof of Gödel's incompleteness theorem, and fast Fourier transform theory. The German mathematical historian Cantor also praised Qin Jiushao as "the luckiest genius". Sutton, the 'father of the history of science', also praised Qin Jiushao as one of his people, his time, and indeed one of the greatest mathematicians of all his time. ”
Cai Tianxin also mentioned that Qin Jiushao's other and more important mathematical work is called "Da Yan Qiu Yi Shu", which is the starting point of cryptography now. An important method of cryptography is to use this 'great derivation of one technique', coupled with Euler's theorem, to become the main tool of our modern cryptography. ”
Qin Jiushao's "positive and negative formula" has pushed the numerical solution of higher-order equations in China to a new stage, and his simple procedure is still common in modern mathematical calculations. Cai Tianxin said that the problem of "positive and negative prescription" was difficult in ancient times, even now, "Qin Jiushao thought of a very clever method, reducing a lot of computing, which is equivalent to making great improvements to the computer." This is a technique used 800 years ago, and this technique is ahead of its time. Now called Qin Jiushao algorithm, common throughout the world. ”
Clarification and clarification of Qin Jiushao's name through in-depth research
Everyone should pay more attention to and promote Qin Jiushao
Some people may wonder: Since Qin Jiushao has done such a great mathematical work, why is his popularity not ranked among Chinese mathematicians? When it comes to ancient Chinese mathematics, many people think of Zu Chongzhi, and few people will think of Qin Jiushao first. Why?
Cai Tianxin believes that the reason for this situation is related to the fact that people at that time could not understand his profound learning and did not know how important his mathematical work was, and on the other hand, it was also related to some setbacks encountered in his later life. Due to some of the reasons of the opponents, Qin Jiushao's reputation was not a small controversy.
Cai Tianxin has a strong interest in Qin Jiushao's perennial exploration. In his essay collection "Mathematical Legends: Those Unattainable Characters", he is specially included in the chapters of "Qin Jiushao, Daoguqiao and the Nine Chapters of the Book of Numbers". In order to write this article well, Professor Cai Tianxin visited Qin Jiushao's birthplace of Anyue in Sichuan, Mei County in Guangdong Province, and also visited Fan County, Henan, where his ancestral home was. In order to clearly explain Qin Jiushao's moral doubts, Cai Tianxin conducted many field visits and multi-party verification and consultation, and proposed that the stigmatization of Qin Jiushao was untenable, thus clarifying and justifying Qin Jiushao's reputation.
Cai Tianxin mentioned that in Qin Jiushao's time, science in the Western world had not yet come in, so his mathematical thinking was all on his own. Like many scientists in ancient Greece, Qin Jiushao also traveled thousands of books and traveled thousands of miles. He traveled a lot of places throughout his life, which gave him ample opportunities to master a lot of basic knowledge.
Cai Tianxin, a native of Zhejiang, also mentioned the deep relationship between Qin Jiushao and Zhejiang, "Qin Jiushao's ancestral home is Fan County, which once belonged to Shandong and is now part of Henan. Later, his ancestors moved to Anyue, Sichuan. Qin Jiushao was born in Anyue, Sichuan. He used to live and roam in many places. One of the most important places is Zhejiang. In Zhejiang, he had the opportunity to read a wide range of books, learn from some predecessors, and obtain basic scientific and technological knowledge, especially mathematical knowledge. ”
Cai Tianxin also issued his sincere appeal in the lecture: "This year is the 760th anniversary of Qin Jiushao's death, he is a thoughtful and tasteful scholar. We should not permanently obscure the glorious achievements of Qin Jiushao, a great mathematician, for the sake of paper questioning without empirical evidence. The pearl should not be dusted, but more attention should be paid to and promoted Qin Jiushao, a great mathematician. ”
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