A Man of Science and Engineering in Troubled Times Wandering in the Late Qing Dynasty

Chapter 645 Pain
At the University of Göttingen, Li Yu encountered many students with empty sleeves. The overall situation was a little worse than that at Cambridge.

After seeing Li Yu, Hilbert said: "Academician Li Yu, it's great that you can come! I just wrote a letter to the newly appointed Minister of Science, Art and Public Education, hoping to hire a visiting professor to come to Gottingen. Gen lectures. I applied for a fee of 5000 marks, which was later increased to 15000 marks, but now it seems that marks are not enough. Inflation is terrible.”

Li Yu smiled and said: "I happen to be in Paris and stopped by. I don't need any funds. And I'm not that good at pure mathematics."

"Paris? It is now a place where politicians gather, discussing how to carve up the entire Europe. I am not interested," Hilbert said, then pointed to a lecture hall in front, "There is a mathematics lecture today. After the war, mathematics It’s rare to return to campus, and I really want to know if there will be any new progress after four years.”

"I am very happy to appreciate the true wisdom of human beings." Li Yu said.

Hilbert looked at his pocket watch and said, "There is still time. Let's wait for another five minutes. Amy Nott will finish her lecture."

——The female mathematician who proposed the famous Noether's theorem.

Li Yu said: "Göttingen is very open and has allowed female lecturers to exist."

"It took a lot of effort to get it," Hilbert lamented. "Three years ago, Noether was invited by Director Klein to come to Göttingen. I wanted to arrange a teaching position for her at that time. , but was dismissed by historians and linguists at a conference of philosophy professors.”

Li Yu wondered: "What does the appointment of mathematics lecturers have to do with linguists?"

"Let's go and listen to what's new. I hope that in four years' time, Göttingen's mathematics will still not fall behind," Hilbert took a puff of his pipe and added, "By the way, this is Li Yu gentlemen."

Not long after, Amy Nott walked out of the classroom and said to Hilbert: "Professor, are you waiting for me?"

"How can I compare with Ms. Curie." Amy Nolte said modestly.

"Yes, she has proven her ability," Hilbert said, "otherwise they still would not be able to accept the existence of a female lecturer."

Amy Nolte and Weyl also looked forward to it.

Hilbert explained: "The Department of Mathematics at the University of Göttingen is still classified as the Department of Philosophy. Linguistics and history are also in the Department of Philosophy. When we hire professors, they must be approved by the Philosophy Professors' Conference. However, they do not treat women The prejudice is too great, and many requests have been rejected. I simply can’t imagine that the candidate’s gender has become a reason to oppose Nott’s promotion to lecturer. They seem to have forgotten that this is a university and not a bathhouse!”

Li Yu said: "I read several scientific journals in Paris, and it seems that Ms. Noether proposed the extremely creative Noether's theorem last year and wrote a very valuable paper."

——The year 1900 was truly the most flag-raising year in history.

Several people came to the mathematics lecture hall. Weyl had arrived long ago, but Klein did not attend due to health reasons.

Li Yu smiled and said: "I am also honored to meet an outstanding female mathematician like Marie Curie."

Amy Nott doesn't talk much and has a somewhat reserved personality. On a campus that's basically all male, that's all she can do.

Noether's achievements were not low, but in the 20th century, those who engaged in mathematics were not as famous as those who engaged in physics. There were too many explosive discoveries in physics, while mathematics has been moving forward calmly at its own pace, hiding its merits and fame.

Hilbert looked at the report card: "Brown, a mathematician from Norway, is going to talk about Goldbach's conjecture. It's really exciting. Since I proposed it in 1900 problems in 23, there has been no progress. ”

Euler's statement is the most widely circulated Goldbach's conjecture. Strictly speaking, it can be called the "Strong Goldbach Conjecture", also called the Goldbach Conjecture about even numbers.

Amy Nott said adoringly: "Mr. Academician, it's such an honor to meet you!"

Li Yu asked: "What is the content of today's lecture?"

Goldbach's conjecture shouldn't require too much introduction because it is so famous, so I will briefly mention a few key points.

European universities are currently biased against women, and Germany is the most conservative among them.

(Note: This is a modern statement, because in Euler's time, 1 was still a prime number. Goldbach's original version was: any integer greater than 2 can be written as the sum of three prime numbers. Don't worry about this detail.)
Then God Euler read Goldbach's letter and said: I have a bolder idea. Any even number greater than 2 can be written as the sum of two prime numbers.

Only Li Yu felt a little dizzy, which was completely beyond his ability.

Goldbach first proposed his conjecture in his letter to Euler: "Any integer greater than 5 can be written as the sum of three prime numbers."

Some are strong and some are weak. The "weak Goldbach conjecture" is: any odd number greater than 5 can be written as the sum of three prime numbers.

The "strong Goldbach conjecture" is obviously much more difficult. If it is true, the "weak Goldbach conjecture" will naturally also be true.

One more thing to mention, in 2013, the "weak Goldbach conjecture" had been proved by the Peruvian mathematician Harold. The process was quite interesting. He first proved that all odd numbers greater than 10 raised to the power 30 can be written as the sum of three prime numbers; then he used a computer to verify all odd numbers less than 10 raised to the power 30 one by one. Thanks to the powerful computing power of computers.

Li Yu didn't know much about Brown, a mathematician, nor did he understand extremely profound number theory. He only generally knew that Brown came to a conclusion by improving the sieve method of Eratosthenes: all even numbers that are sufficiently large can be Expressed as the sum of two numbers, the number of prime factors of both numbers does not exceed 9.

(For example, 30=2×3×5, there are three prime factors)
In other words: all sufficiently large even numbers can be written as the product of no more than 9 prime numbers + the product of no more than 9 prime numbers.

The brief expression is: "9+9".

This is why people always mention "1+1" when they hear Goldbach's conjecture. This is the ultimate goal.

(I remember when I was a kid in class, the teacher said that proving 1+1 was proving Goldbach’s conjecture, and he was the most powerful mathematician. At that time, I always wondered, what’s so good about proving this?

——Well, it seems that in order to prove 1+1, Russell used a very complicated axiomatic language, which is hundreds of pages long and cannot be understood by ordinary people. )
Anyway, Brown blazed a trail, and he himself proved 9+9.

Since then, mathematicians have continued to make progress. In 1924, German mathematicians proved "7 + 7";
In 1956, Wang Yuan of my country proved "3 + 4"; later he proved "3 + 3" and "2 + 3".

The most successful one on this road is definitely Chen Jingrun’s “1+2”.

It is said that this is the limit of the sieve method. If you want to completely prove Goldbach's conjecture, you must find a new mathematical method. I don't know how long it will take.

Li Yu had long been unable to keep up with Brown's speech. After he finished speaking and everyone clapped excitedly, Li Yu caught up with the rhythm.

Hilbert came to the stage and said excitedly: "In national life, every country can only prosper when it coordinates and lives in harmony with its neighboring countries; national interests require not only within each country, but also Establishing a universal order in the relations between nations - also in scientific life.

"Mr. Brown's results are very important. After many years, I saw the wonderful axiomatic method instead of the calculation diagram of ballistics. I believe that all knowledge that is subject to scientific thinking must be developed into a theory. Governed by axiomatic methods, governed by mathematics.”

Hilbert was still immersed in his work of axiomaticizing mathematics.

But just like Einstein's research on grand unified theory in his later years, Hilbert's axiomatics are a bit vague. Hilbert was more lucky. He saw someone break his illusion before he was alive, and he finally got an explanation.

——The mathematical genius named Gödel was still in middle school at this time.

After the mathematics conference, Hilbert invited Li Yu to dinner. They were very short of supplies. There were only bread and sausages on the table, and a small amount of dipping sauce.

Hilbert said bitterly: "If the mark continues to depreciate, we won't even be able to eat sausages."

Li Yu said: "The professor's prediction may come true."

Hilbert was stunned for a moment, "I don't want to make such a prediction."

-

Li Yu did not stay in Göttingen for too long and continued to Berlin two days later.

Einstein had already received Li Yu's telegram and rode a bicycle to the train station to greet him.

"Hello, Mr. Li Yu from the East!" Einstein said, holding his bicycle. "Welcome!"

"Hello, Professor Einstein," Li Yu looked at his bicycle, "Are you sure you can use it to pull me back?"

Einstein said confidently: "Of course, get in the car!"

Not long after he rode, he couldn't hold on: "From the perspective of energy conservation, I have consumed all the food I have eaten today."

Li Yu smiled and said, "Then let's change."

The two of them took turns riding their bicycles towards the Academy of Sciences.

Einstein asked on the way: "Did you get any news about the expedition team while you were in England?"

"Observing a solar eclipse?" Li Yu said, "I met Eddington himself, and he was very well prepared for this expedition."

Einstein said: "Fortunately, someone understands the significance of the theory of relativity, otherwise the German Academy of Sciences will not be able to send another expedition team within a few years. Germany's economy has been completely ruined. The elevator in the apartment where I live cannot operate, and the heating Even more problematic, how can the Academy of Sciences still have money to support ocean expeditions after spending the entire winter shivering?"

After arriving at the place, they were all a little out of breath. Einstein said: "It is difficult to find a car now, and refueling is also a problem. Fortunately, bicycles can save money."

"It's great to be able to exercise," Li Yu said with a smile, and then asked, "Is Professor Planck here?"

"Yes, let's go and visit. Maybe he will be happier to see you." Einstein said.

"What's wrong, professor?" Li Yu asked.

Einstein said: "Two years ago, Professor Planck's daughter died in childbirth, which made him heartbroken; last year, his youngest son was wounded and died in the war, which was a great blow to him."

Planck's pain was not over yet. His other daughter married the husband of her dead sister and unexpectedly died in childbirth at the end of this year.

Of his four children, only his youngest son survived a prison sentence in France.

The two entered Planck's office, and Li Yu could see that Planck was obviously much older.

"Professor, your misfortune makes me very sad." Li Yu said.

Einstein also said: "I hope you will not be overwhelmed by pain."

"Please sit down, both of you," Planck forced a smile, and then said, "I understand now that only when a person feels the suffering caused by the war in himself, this suffering will produce pain. And loss Only then did I realize that I had underestimated Carl (my son who died in the war) in the past.

"Before the war, he had been letting things slide and could not settle down to a noble profession, and I always blamed him. Until he joined the army and died in a war in which Europe was trying to destroy its own civilization.

"Without the war I would never have known his worth; now I know his worth, but I must lose him."

Li Yu sighed: "In ancient Chinese proverbs, losing a child in middle age is one of the three major misfortunes in life. Please teach me how to express my condolences."

Planck said: "I am doing self-education. I understand that we have no right to get all the good things that life brings to us; misfortune is the natural state of man, but it is not an inevitable state. There are many precious things in the world, life The value of life is determined by the way people live, so even after suffering, people return to their duties again and again, to show their love to their dearest people, this kind of love. As much as they would like to experience.”

After experiencing these pains, Planck gained some profound insights into life.

Li Yu could only find something good to make him happy: "When I was in France and the UK, I had many contacts with the scientific community, and several of them were qualified to be nominated for the Nobel Prize. They were all willing to give their nominations to you, Professor."

"I'm glad they didn't choose to be hostile to the German scientific community because of the war," Planck said.

There was light in his eyes again, because he knew very well that if they wanted to restore Germany's reputation, science was a very important path, and it was also what they were best at.

At this juncture, he cannot fall.

Einstein said: "Professors Born, Lorenz, Wien and Sommerfeld are also willing to nominate you."

"I actually gave you the general theory of relativity in my nomination this year," Planck said.

"The results of the solar eclipse haven't come out yet, it's too late," Einstein shook his head and said, "There is a high probability that Stark will win."

Planck finally won the Nobel Prize that was reissued in 1918 last year, and this year's Nobel Prize will be awarded to Stark.

As for Li Yu's plan, he can only postpone it temporarily, and there is no rush anyway.

The Nobel Prize committee's selection of Planck and Stark is very representative. One of them is a theoretical physicist and the other is an experimental physicist.

Stark, like Leonard, dislikes theories and people who engage in theories. He is also very anti-Semitic.