The mathematics seminar that day continued, but now it became more of a special lecture by Li Yu, because in addition to the mathematics department, there were now many students from other majors.
Of course, Markov and Lyapunov could not stop them. According to the philosophy of the university at this time, it was normal to learn more things, and there were no such strict professional barriers.
At noon, Li Yu was about to go back and have a rest, but was stopped by Zhang Deyi again.
"Are you still talking?" Zhang Deyi asked.
Li Yudao: "There are many more students from the Department of Biology and Department of Geology today. I can't help it. They are too enthusiastic. Some of them are even holding manuscripts."
"You are really popular." Zhang Deyi praised.
Li Yu asked: "Hey, I haven't seen you for two days. Have you gone to worship the statue of Our Lady of Kazan?"
"Of course I went. I first found the embassy in Russia, and sure enough, even the prayer gestures were different. Anyway, I also said 'Amen' and kowtowed in front of the Kazan Madonna statue, praying that I could sign successfully this time.
The British must not get in my way when I issue the "Work Guarantee Regulations"," Zhang Deyi said.
Li Yu said with a smile: "The British believe in Protestantism, and you use the Chinese-style kowtow ceremony in the Orthodox church. I think the Holy Mother may not understand what's going on now."
Zhang Deyi also smiled and said: "We'll talk about it later. If it doesn't work out, I'll go to their church to pay homage when I get to England. By the way, today the Minister to Russia, Hu Weide, is hosting a banquet in the embassy and asked me to invite you to come."
There was no need for Li Yu to refuse, so he said: "It's really rare that a Russian ambassador and a British ambassador get together."
Although Hu Weide and Zhang Deyi were both ambassadors in name, Zhang Deyi had a higher qualification than him, holding a second-rank official title, while Hu Weide held a third-rank official title.
So when Zhang Deyi and Li Yu came together, Hu Weide still respectfully shouted: "Master Zhang."
Zhang Deyi cupped his hands and said: "Mr. Hu, let me introduce you to the outstanding Western scholar Li Yu. He has been giving lectures at the Royal University of St. Petersburg these two days. I went to see him and it was overcrowded."
Hu Weide said: "I have heard about Mr. Li's great deeds for a long time. When I see him today, he is really a young hero."
Li Yu also said politely: "Nice to meet you!"
"You two sit inside, and I specially arranged for the chef to prepare local dishes."
Hu Weide was a native of Zhejiang. He later served as the Deputy Minister of Foreign Affairs in the Tang Shaoyi Cabinet of the Republic of China, and later became the Director-General of Foreign Affairs during the Beiyang Government. Even when Duan Qirui just stepped down, he was appointed to concurrently serve as the Prime Minister and exercise interim administrative powers.
The luncheon prepared by Hu Weide was very rich, including West Lake fish in vinegar, Dongpo pork, Longjing shrimp, steamed pork with lotus leaves and rice flour, and beggar's chicken, all of which are famous Zhejiang dishes.
After two days of eating Russian cabbage, pickled cucumbers, and an unspeakable amount of kvass drinks, Li Yu felt extremely friendly when seeing these things.
Hu Weide said: "I heard that Mr. Mathematics was taught in the university hall?"
Li Yu replied: "Exactly."
Zhang Deyi explained: "Li Yu was actually invited to go to Sweden this time, and the King of Sweden personally awarded the mathematics medal."
Hu Weide gave a thumbs up: "It's really amazing! Sir, he is really the number one person in the field of arithmetic in my university! It's a coincidence that when Mr. Hu won the exam, he also relied on his arithmetic."
Zhang Deyi thought for a while and said: "If I remember correctly, in the 13th year of Guangxu's reign (1887), the imperial court decided to add arithmetic as a subject to the imperial examination. The next year, Mr. Hu won the arithmetic exam."
"You remember correctly, Mr. Zhang," Hu Weide said, "Actually, we have the same background. The Shanghai Cantonese Dialect Center where I graduated is the same as the Jingshi Tongwen Hall where I graduated. However, I majored in arithmetic and French in the following year. As for
I only learned Russian a few years ago.”
The Shanghai Cantonese Dialect Center was established in the second year after the establishment of the Tongwen Hall in the Capital. It was the first foreign language college established in Shanghai. Like Tongwen Hall, it later added arithmetic, astronomy and other subjects.
Zhang Deyi said with a smile: "Master Hu has learned much more solidly than me. After all, he can still pass the math exam. I have only learned one English subject in so many years."
Hu Weide said: "At that time, I thought that after passing the arithmetic examination, I could only enter the arithmetic school of the Imperial Academy, and then enter the Qintian Prison. I didn't expect that I could become the minister to Russia now. I think it was because there were very few people in the DPRK who understood Western learning and foreign languages.
Therefore.
However, since I have been to several countries as ambassador, I have also understood that the arithmetic level in our school is far behind. As for my arithmetic level, it is even more insignificant, and it cannot be compared with Mr. Li Yu's world-famous power in the West."
Li Yu said: "Master Hu, you are too polite. Now you are engaged in diplomacy and you are also working hard."
The School of Arithmeticology was established in the early Qing Dynasty, and during the Qianlong period it was incorporated into the Imperial College, with a quota of 60 people. Although the number has been expanded several times, it still only belongs to a niche category.
There are still 250 people in the Imperial College who can study Confucian classics every day.
There is a big gap between mathematics students and the huge group of scholars who study the Four Books and Five Classics and aspire to pass the exams in the whole society. In short, the number of people who studied algorithms in the Qing Dynasty was a very small minority.
And from the perspective of the future of arithmetic students, although the Qing Dynasty gave arithmetic students the right to test as proctors and participate in scientific examinations, the establishment of the arithmetic school mainly served the Qin Tian Jian, and the math students were trained as reserve personnel of the Qin Tian Jian.
Yeah, it's hard to achieve anything big.
Hu Weide was able to stand out not only because of his outstanding personal ability at that time, but also because he caught up with the Westernization Movement in the late Qing Dynasty. People had unlimited fear and admiration for the West. He was riding the wave of the times.
Hu Weide pointed to a book called "Fractals and Chaos" and said, "Master Zhang brought this to me from St. Petersburg University. I'm ashamed that as a mathematician, I can't understand it at all."
Li Yudao: "Academics have specializations. If you want to truly understand mathematics, you must at least study it for many years like a scientific examination of classics and history."
When Hu Weide studied arithmetic, he could only learn mathematics at the level of the first or second grade of junior high school, which was basically some application problems of mathematics.
Hu Weide poured a glass of daughter's red wine: "I am impressed by how I can make my name famous among foreigners by toasting my husband with wine from my hometown, and by doing so in a scientific way."
Li Yu picked up the wine glass: "Science is not just for foreigners. Sooner or later we can catch up."
Hu Weide said: "I hope, the current situation... By the way, Sir, would you like to meet the Tsar?"
Li Yu shook his head: "Forget it, unless he orders me to come to the Winter Palace, it's better not to take the initiative to see me."
Hu Weide said: "Why? After all, Tsar Nicholas II is the only emperor who has been to the East, and he is relatively friendly to us."
"It's all an illusion," Li Yu knew very well. "In the eyes of the Tsar, we yellow-skinned people are the source of the 'yellow peril' theory."
Hu Weide was stunned. Although he was in the diplomatic field and did not have many opportunities to see Nicholas II in person, he had actually felt it in his heart for a long time. He could only say: "But the Tsar still respects scientific researchers to some extent."
Li Yu said with a smile: "I still feel more free at Petersburg University. They also respect me very much. I feel more comfortable with them."
Hu Weide said: "Sir, you are open-minded!"
I don’t know if he learned it from Yu Geng. Ambassadors who go abroad often bring a cook with them. Li Yu enjoyed the delicious food at the embassy in Russia.
Thanks to Hu Weide's background in arithmetic, even though he didn't know much about it, he was still able to talk quite speculatively.
After several glasses of wine, Hu Weide wanted to attend Li Yu's lecture, but then he thought that he couldn't even read his books, so he had no choice but to give up.
Back at St. Petersburg University, Li Yu went to the auditorium and continued the afternoon mathematics seminar with Markov and Lyapunov. It lasted for an hour and a half, with an intermission as usual.
Li Yu suddenly saw several students walking over accompanied by an old scholar with a white beard.
The student said: "Professor Pavlov, we listened to the Chinese Li Yu's lecture here this morning. His theory on fractals and chaos is very interesting."
Well, this big boss also showed up.
Pavlov said: "I also read his previous article on the expansion of the law of entropy increase, and it did involve biology. Before that, I really didn't think that the laws of thermodynamics could be related to our biology."
The student said: "Not only that, after listening to his lecture in the morning, it seems that chaos theory is also permeated in all subjects. I wonder if it has applications in our biology."
Another student saw Li Yu and said to Pavlov: "Professor, that's him."
Pavlov is now in his fifties and is very strong. He just established the theory of conditioned reflexes last year and is now famous. The year after that, in 1904, he will become the first Russian scientist to win the Nobel Prize.
Li Yu stepped forward and said hello proactively: "Hello, Professor Pavlov!"
Pavlov also studied in Germany, so Li Yu could also communicate with him in German.
Anyway, at this time, being proficient in multiple languages was an important indicator of educational level. Even Tsar Nicholas II could speak fluent French, English and German in addition to his native Russian.
That's why Li Yu spared no effort to learn foreign languages, otherwise people in this era would really think that your education was lacking.
Pavlov shook hands with him: "Li Yu, right? You are indeed young. My students have often mentioned you in the past two days. You can teach mathematics to the point where even students from the biology department come to listen. You are really the royal family of our St. Petersburg."
The first one in the university.”
Li Yu smiled and said: "Maybe it's because what I wrote is simple and easy to understand."
"Being able to make difficult things easy is a skill. You are very talented in lecturing, but my students often complain about me." Pavlov said.
The students at the back quickly said: "Professor Pavlov, we are not complaining!"
Pavlov smiled and said: "How do I know? Besides, look at how excited you are after listening to his lecture today. Your expressions can't hide it from me."
The student quickly explained: "Professor, it's all because what Li Yu said is very novel."
Pavlov ignored the students and continued to say to Li Yu: "I can see that you are very divergent thinking. My students said that your fractal and chaos theory can be used in biology. I am very curious and want to learn more about it."
."
As expected, he was a big shot, and he asked tough questions when he came up.
But fractals and chaos have been integrated into every corner. Li Yu said: "Fractals and chaos are everywhere. Professor, you should be familiar with animal anatomy. In fact, fractals are hidden in anatomy. Bronchial tubes and blood vessels are all bifurcated.
There are also subtle structures, all of which are fractal structures.”
Pavlov raised his eyes: "When you say that, it's really true. Why didn't I think about it?"
Li Yu continued: "As for chaos, it is more common. Chaos is hidden in the neurology you study, Professor. Our brains, and of course all animals, are nonlinear networks composed of nerve cells. Once it appears,
'Nonlinear' often leads to chaos."
Pavlov listened carefully and praised: "It makes sense, it's very well said!"
Li Yu continued: "Even the beating of the heart itself is a kind of chaos theory. If you think about why so many cells can vibrate in unison, it is a wonderful chaos model in itself; if you leave aside individuals, the population of living things can reproduce as large as
, the development and spread of various epidemics will have the shadow of chaos."
The vitality of chaos theory is extremely tenacious. Even if it has developed to the era of Li Yu, the research enthusiasm of various scientists is still very high.
Li Yu's book is just the beginning. He cannot cover all aspects of chaos theory at once.
Pavlov put his hand under his nose, thought for a while and said: "Professor Mendeleev told me this morning that communicating with you can increase the breadth of thinking. I didn't expect it to be true. I will carry out dissection and research in the next few days.
This 'chaos' I have always ignored before! It seems that I also need to read your book "Fractals and Chaos"."
Li Yu directly handed him the book he had been using for the past few days: "Give it to the professor."
Pavlov took out a pen from his pocket: "Use my pen."
"Your pen?" Li Yu didn't know why.
Pavlov smiled and said: "Why, I see you have signed for them, can't you sign one for me?"
"Of course," Li Yu said with the same smile, "Actually, I wanted to ask you for a signature."
"I have long heard that you Chinese like to reciprocate with courtesy. No problem. I will ask the students to give you a signed book later."
Pavlov looked through the book "Fractals and Chaos" in his hand and said with emotion: "It's interesting. When I first entered St. Petersburg University, I also studied in the Department of Physics and Mathematics for a year. It's really nostalgic to see the mathematics book now.
Do you mind if I come into the auditorium to listen?"
Li Yu said: "Of course, I also ask the professor to correct me!"
Li Yu's visit to St. Petersburg University was also very fruitful. Lyapunov was a professor of mathematics after all, and Li Yu specifically asked him to solve a mathematical problem that he was good at, a method for identifying several numerical values of chaotic motion.
Lyapunov was very concerned after getting the "task". He spent all his spare time doing calculations day and night in the past few days, and finally finished it just before Li Yu left on the fourth day.
Li Yu looked at the more than ten pages of manuscript in his hand and was very grateful: "Thank you Professor for your hard work."
Lyapunov said: "You helped me give lectures for a few days. This is what you should do."
"Professor, don't worry, I will definitely include your results in the second edition of "Fractals and Chaos" and name it after you, called the Lyapunov index." Li Yu said.
Lyapunov said happily: "It is an honor for me to leave my name in such an excellent theory!"
This is the famous Lyapunov index in later generations, an inescapable determination method in chaos theory. It is specially used to determine the chaotic nature of a system. It can even be intuitively seen through images whether a system is a chaotic system.