Li was born in Daxing (now Daxing County, Beijing), and his father Li Tong was promoted to Tai Shou of Daxing. Ye Li is very smart since she was a child and likes reading. He studied in Yuanshi County (now Yuanshi County, Hebei Province) and was very interested in mathematics and literature. "A Brief Account of Famous Officials in Yuan Dynasty" said: "Gong (referring to Ye Li) studied when he was young, and his books were always open, enlightened and had the wind of adulthood."
Ye Li wrote many books in his life, but he was most proud of measuring the round sea mirror. On his deathbed, he said to his son Ke Xiu, "I have written all my life, but I can burn to death. Although the book "Rounding the Sea Mirror" is decimal, I have been thinking hard and devoting myself wholeheartedly, and someone will know it later. Can it be widely circulated and last forever? "
Ye Li's mathematical research focuses on celestial magic. At this time, celestial magic has been produced, but it is still immature, just like a small tree, which needs careful cultivation. Through his efforts, Ye Li made it grow into a big tree with lush foliage.
As an accomplished mathematician, Ye Li has the same spirit as scientists throughout the ages, but also has her own unique views:
1. Insist on scientific research under extremely difficult conditions and never stop working. Ye Li is in a turbulent era, especially after he abandoned his official position and retired. The environment for scientific research is very difficult. He is often unable to survive because of hunger, but he is still calm and enjoys giving lectures and writing books. He also works hard for math research. On his deathbed, he said to his son Ke Xiu: "Although the book of measuring the circle of the sea mirror is a decimal, the five permanent members have worked hard for it, and someone will know it in the future."
2. Insist on scientific truth, not wavered by gossip. Mathematical research was despised in the society at that time, and Ye Li's work was rarely understood by scholars at that time. Two books, "Measuring the Circle of the Sea Mirror" and "An Ancient Analysis", were not published until 30 years after his death.
3. Be good at accepting the knowledge of predecessors and taking its essence. When someone asked about learning from Ye Li, Ye Li replied: "There are three things in learning: you can't get the essence if you accumulate more, and you can't get the depth if you get the essence." That is to say, we should get rid of its dross, take its essence and make it our own thing.
4. Oppose the profoundness and vulgarization of the article, and advocate that the article is for others, not for yourself. The preface to Yi Gu Yan Duan says: "Today's calculators may not have the merits of Liu (and Li), but they are obsessed with seeing things and refuse to say that people only care about each other's mistakes, so they are afraid that scholars will peek at them." His Yi Gu Yan Duan is a work under this proposition.
Throughout Ye Li's life, he is worthy of being a model for a generation, both as a man and as an academic. During his tenure as governor of Zhou Jun, he was honest and clean, personally in charge of the cashier, and meticulous. It is reported that the cashier in Zhou Jun is "an irregular mistake". In the turbulent environment at that time, an honest official like Ye Li was really valuable. Ye Li said in Jing Zhai Gu Jiu that this is a portrayal of his being an official. He sympathized with the people and faced the slaughter and plunder of the Mongolian army. He not only expressed great indignation in his poems, but also urged Mongolian rulers to "stop conquering" when meeting Kublai Khan. He loved science all his life, pursued freedom, and never went to bring disgrace to oneself for fame and fortune. He doesn't trust famous scholars academically and dares to break through the shackles of traditional ideas. Although he was a scholar, he specialized in mathematics when he realized its importance. This action itself is a criticism of traditional Confucianism, because in Confucian view, mathematics can be both bright and professional. At that time, the prevailing neo-Confucianism, the neo-Confucianism in Zhu Cheng, even regarded the study of science and technology as a "plaything" and described mathematics as a "poor skill in 1999". In Zhu's works, he rudely criticized these erroneous views and pointed out that "obstacles should not be criticized".
It is worth noting that Ye Li's thoughts are deeply influenced by Taoism. Taoism advocates nature, which is undoubtedly conducive to guiding people's eyes to natural science. Zhuangzi's view of nature even became Ye Li's ideological weapon to resist idealism. He said: "it is inevitable for people who are skilled in both aspects to become a skill." People who have progressed from technology to Taoism say that a stone is as heavy as a wheel on one shoulder, which is beyond the reach of saints? " (Yi, the official name of the Yellow Emperor; Wei Xiao, the name of stone and edge, is the name of ancient craftsmen), that is to say, from the perspective of practical application of skills, the rites and music made by saints can also be regarded as a skill; As far as natural law is concerned, the tools used by craftsmen are also appreciated by saints. If you associate Ye Li's words with Zhuangzi's "Where the Tao lies, the saints respect it", it is obvious that Ye Li is influenced by Zhuangzi Thought. Obviously, he thinks that this skill of mathematics is also "where the Tao lies" and should be.
Ye Li also believes that although the number is infinite, it can be known. He said: "It's hard to say the number difference, but it can be; The forecast figures cannot be bad, nor can they be bad. Why? In the darkness, there is an inherent light. If the husband shows Zhao Zhao, there are also natural numbers. If there are unnatural numbers, there are also natural reasons. " Ye Li's thought can also be traced back to the theory of Laozi and Zhuangzi. Zhuangzi said: "Fu Zhaozhao was born in darkness, and ethics was born in invisibility." Laozi said: "People can live in the land, the land can live in the sky, the sky can live in the Tao, and the Tao is natural." Ye Li further pointed out: "The first one comes from nature, and I want to revive the official leader with strength and poverty. If I can deduce the theory of nature and find out the number of nature, I will be far away, like a ghost, and no one is absent. "
Ye Li not only has advanced philosophical thoughts, but also can carry out tenacious scientific research under extremely difficult conditions. When he was writing a book in Tongchuan, his room was very small and he often had to struggle for food and clothing. However, he enjoys writing books and never stops working. His student Jiao said that he was "hungry and cold, unable to stand on his own feet and feel sorry for himself" and "wasted a day" in "being displaced and frustrated". In addition, he was good at selecting the best from the rough and critically accepting the knowledge of his predecessors. As he himself said, "learn three things, accumulation is not in essence, and essence is not in depth." These excellent qualities are the important reasons for Ye Li's outstanding academic achievements.
In Ye Li's time, mathematics was neglected. But Ye Li persevered in the pursuit of truth. He said in Preface to Measuring a Round Sea Mirror: "Look at what I made up, look at my painstaking efforts, and there are 100 people who laugh at me. But if my income is complacent, I would rather laugh at others. " Ye Li is not only knowledgeable, but also devoted to educating students and being good at persuading them. Later generations praised Ye Li for her kindness in guiding and educating his people. His disciples lived in that era, and he never said that Wen was successful "(Yes, posthumous title). Ye Li wrote a glorious page in the history of science in China with her lifelong efforts, which is deeply missed by people. Volume one.
The Rounding Sea Mirror identifies miscellaneous notes through the round city schema in Volume I, explaining the total rate names of various length names, giving the current positive numbers of various length values, and the formula set containing the relationship between various quantities. Volumes 2 to 12 contain * * * 170 questions and their answers. There are 148 questions in the book * *, and the method of 182 is to list equation solutions, including 3 1 linear equation, 106 quadratic equation, 24 cubic equation, 20 quartic equation and 1 cubic equation.