Cover news reporter Zhang Jie
Bashu Land, Zhong Lingyu Xiu. This land has nourished many brilliant cultural celebrities. Qin Jiushao (1208-1268) was a famous southern Song dynasty mathematician born in Puzhou (present-day Anyue County, Ziyang). Ancient Chinese mathematics reached the peak of prosperity in the Song and Yuan dynasties, and a large number of accomplished mathematicians emerged, Qin Jiushao and Li Ye, Yang Hui, Zhu Shijie had the most outstanding achievements, and were known as the "Four Greats of the Song and Yuan Dynasties". George Sutton, the "father of the history of science," argues that "Qin Jiushao was one of the greatest mathematicians of his people, of his time, and indeed of all his time." ”
Qin Jiushao studied astrology, musical rhythm, arithmetic, and construction, and his book "Nine Chapters of the Book of Numbers" was included in the "Yongle Canon" and the "Outline of the General Catalogue of the Four Libraries". Many of these calculation methods and empirical constants still have high reference value and practical significance, known as the "treasure book in arithmetic", representing the advanced level of Chinese mathematics at that time and occupying a lofty position in the history of world mathematics.
Qin Jiushao's mathematical thought is an important part of China's excellent traditional culture. Qin Jiushao was a polymath who studied astrology, musical rhythm, arithmetic, and construction, and was also a meteorologist who was the first to define rainfall and snowfall. Behind this great mathematician and scientist, what kind of valuable growth experience does his learning have, and what is the value and significance of his knowledge for us today and here and now? What is the charm of ancient oriental mathematics? At 7:30 p.m. on October 18, Cai Tianxin, a professor of mathematics, writer and traveler at Zhejiang University, will be a guest in the "Hall of Fame" and give a lecture at the Sichuan Provincial Library with the title of "Qin Jiushao, Daoguqiao and China's Residual Theorem".
Who is Qin Jiushao?
Erudite and versatile, he specializes in arithmetic and construction
Zhou Mi wrote in the "Sequel to The Miscellaneous Knowledge of Yan Xin" that Qin Jiushao was "extremely clever, and the stars, musical rhythms, arithmetic, and even construction were all exquisitely studied, and he learned the poetry from Li Meiting, and the games, balls, horses, and bows and swords could not be known." Chen Zhensun said in volume XII of the "Explanation of the Records of Zhili": "Qin is erudite and versatile, and the especially the calendar, all the calendars of recent times, are transmitted to Qin. At the same time, when titled the Chongtian Calendar of the Ji Renzong Dynasty and the Epoch Calendar of the Huizong Dynasty, it is said: "This second calendar is close to the Shu people Qin Jiushao Daogu. The Chronicle of Anyue County (Sichuan People's Publishing House, 1993 edition) also records its talent in construction: "Qin Jiushao moved with his father to Huzhou (present-day Wuxing District, Huzhou City, Zhejiang), built a house outside the West Gate, designed and constructed by Qin Jiushao, the hall was divided into 7 rooms, and then the column room, only 1 middle hall, 7 zhang in length and width, and its grandeur and spaciousness showed his talent in architecture. ”
Qin Jiushao basically spent his youth in Sichuan, and he had a period of studying with his father in Beijing. Qin Jiushao, in the "Nine Chapters and Prefaces to the Book of Numbers", also wrote about his study experience of "serving zhongdu in his early years, because he had to visit and learn from Taishi". Taishi was a court official in charge of the astronomical calendar, and was actually some of the officially recognized astronomers and mathematicians at that time. That is to say, because of his father's relationship, Qin Jiushao had the opportunity to visit many famous scholars of the imperial court in the capital city (Lin'an, the capital of the Southern Song Dynasty, present-day Hangzhou) in his youth, such as astronomical calendarists, writers, architects, etc., and learn from them, which was of great benefit to enriching what he had learned and broadening his horizons. Qin Jiushao's "servant Zhongdu" was short-lived, and his father served in the Beijing Division for less than 10 months. Qin Jiushao also mentioned in the "Nine Chapters and Prefaces to the Book of Numbers": "I also tasted mathematics from the hidden gentleman. From this, it can be seen that after returning to Sichuan, Qin Jiushao continued to seek advice from scholars living in seclusion in Shuzhong.
Cai Tianxin has conducted in-depth research on Qin Jiushao's mathematics and life, and has visited Anyue, the place of birth, and Meizhou, the place of death. In his view, Qin Jiushao was erudite and multi-talented, and specialized in astrology, musical rhythms, arithmetic, and construction, which also laid the foundation for him to absorb the essence of ancient Chinese mathematics, apply mathematics to social life, and prove that Oriental mathematics is known for its practicality and structure. In the "Nine Chapters and Prefaces to the Book of Numbers", Qin Jiushao also advocated applying what he had learned. He also put forward many interesting and practical questions in the "Nine Chapters of the Book of Numbers", such as "pushing the soil gong", "pushing the number of yumi", "counting the land and accommodating the people", "looking at the mountains and high mountains", "counting the stone dams", "counting the cubic camps" and so on. Unlike Western theoretical mathematics, Chinese mathematics is more applied, which is also the biggest feature of the Nine Chapters of the Book of Numbers.
In the "Nine Chapters of the Book of Numbers", Qin Jiushao systematically summarized and developed the numerical solution method of higher-order equations and the one-time congruence group solution method, and created a fairly complete "Great Derivative One Technique" and "Positive and Negative Opening Technique", which is an outstanding summary of the brilliant achievements made by traditional Chinese mathematics in these two aspects. The "Great Yan Qiu Yi Shu" was more than 500 years earlier than the famous Western mathematicians Euler (1707-1783) and Gauss (1774-1855) who studied this problem, and was called "China's Surplus Theorem" by the West, showing Qin Jiushao's lofty position in the history of world mathematics. The "positive and negative equation" has pushed the numerical solution of higher-order equations in China to a new stage, and this simple procedure of his is still used in modern mathematical calculations, more than 500 years earlier than the Rufini-Horner method proposed by the Italian Ruffini (1765-1822) and the Englishman Horner (1786-1837).
It is worth mentioning that in addition to Sichuan, in Cai Tianxin's hometown of Zhejiang, there are also the remains of Qin Jiushao. There was once an old bridge called "Xixi Bridge" on Xixi Road in Hangzhou, which was built by Qin Jiushao. In the early years of the Yuan Dynasty, Zhu Shijie (1249-1314), another great mathematician and a northerner who traveled all over the world, came to Hangzhou and proposed to rename the "Xixi Bridge" to "Daogu Bridge" to commemorate the bridge builder and the predecessor mathematician Qin Jiushao, whom he admired, and personally engraved the bridge name book on the bridge. Later, due to the expansion and reconstruction of Xixi Road, the old bridge was demolished and leveled, leaving only one bus station, the famous road ancient bridge. In 2005, a pedestrian stone bridge was built on the mountain and river 100 meters away from the original site of the Ancient Bridge, which was named Daogu Bridge at the suggestion of Professor Cai Tianxin, and he invited Mr. Wang Yuan, a mathematician and academician of the Chinese Academy of Sciences, to write the name of the bridge. In April 2012, the relevant departments of Hangzhou Held a ceremony to restore the name of "Daogu Bridge". Tang Xiaowei, academician of the Chinese Academy of Sciences, and responsible persons of relevant departments, experts and scholars attended the monument-setting ceremony, and some domestic and foreign media such as Southern Weekend quickly reported on it.
The American mathematical historian George Sutton believes that "Qin Jiushao was one of the greatest mathematicians of his people, his time, and indeed all his times." In 2005, Oxford University Press published The History of Mathematics– From Mesopotamia to Modern Times, which highlights the 12 mathematicians that Qin Jiushao is the only Chinese. In the BBC's elaborate four-episode documentary The Story of Mathematics, Qin Jiushao is also the only Chinese mathematician to appear. So why is Qin Jiushao's popularity in China far less than that of his mathematical peers such as Zu Chongzhi? Professor Cai Tianxin will also unveil this mystery for us in this speech.
Young genius, mathematics professor and poet interprets genius mathematicians
Cai Tianxin was admitted to the Department of Mathematics of Shandong University at the age of 15 and received a doctorate in science at the age of 24. Professor, doctoral supervisor and Qiushi Distinguished Scholar of school of mathematics of Zhejiang University, he has won the National Science and Technology Award and the National Teaching Achievement Award. He proposed the concept of primes and multiplication equations, and his work on the New Hualin problem was praised as a "truly original contribution" by British mathematician and Fields Medal winner Alain Baker. He is also a poet and traveler, who has traveled to more than 100 countries and has published more than 30 literary, academic and popular science works, as well as more than 20 foreign editions. In 2013 and 2019, he won the Naji Naaman Poetry Prize in Beirut and the Kathak Poetry Prize in Dhaka. In 2015, he was selected as one of the first 10 innovative figures in Hangzhou. In 2018, he was invited to CCTV's "Readers" program, the Boao Forum and the University of Iowa International Writing Program.
Since 2000, Cai Tianxin has been invited to give public lectures at dozens of famous universities on 6 continents, including Princeton University, London School of Economics, Australian National University, National University of Singapore, Mexico College, University of Nairobi, more than 100 universities and high schools in China, and other institutions. This time, Professor Cai also spoke as a guest of Sichuan University, Chengdu Seventh Middle School and related bookstores.
The "Celebrity Lecture Hall" is an important cultural activity sponsored by the Office of the Leading Group for the Implementation of the Sichuan Historical Celebrity Cultural Inheritance and Innovation Project, the Sichuan Daily Newspaper Group (Cover News, West China Metropolis Daily), and the Sichuan Provincial Library, and is sought after by the majority of fans. Since the official opening of the lecture in November 2018, the "Celebrity Lecture Hall" has invited experts in the fields of history, humanities and natural sciences, including Li Jingze, Alai, Li Bo, Yu Dan, Mei Zhengzheng, Fang Beichen, Sun Xiaochun, etc., to sit and discuss with the audience, becoming a beautiful cultural business card.
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