Department of Mathematics, Beijing University,

As one of the best universities in the country for mathematics majors, there are countless so-called mathematical geniuses in this department, if this department is only ranked second, then no university's mathematics department dares to say that it is the first, it is such a good existence.

It admits 200 undergraduates every day, half of whom are guaranteed by competitions, and almost all the domestic gold medalists who have won gold medals in the International and Domestic Mathematics Olympiads are here, and it is also known as the first of the four crazy departments.

In addition to the geniuses who were originally in the mathematics department, there are many students from other majors who come to study here, such as computer science, economics, physics, etc., and those who are outstanding in their respective departments come to the mathematics department from time to time for related studies.

The students who study here are divided into two kinds of four classes according to the competition escort students and college entrance examination candidates, so to speak... The competition is very strong, and the pressure here is huge, but as long as he can carry it here, then he is not an ordinary person.

It is also for this reason that geniuses and masters gather, almost all of whom are concentrating on studying hard, and the vast majority of these students will choose to go abroad to continue their studies after graduation, and then... Only twenty percent of the people came back.

Of the 500 people who go out every year, less than 100 come back, and after obtaining their doctorates abroad, many of them choose to stay and work, and some of the most outstanding people become university professors or associate professors, and the middle ones hold important positions in major companies.

For example, mathematical principles play a pivotal role in price models, statistical analysis, financial products, best investment portfolios and other fields, and Chinese people are good at mathematics, which is a normal phenomenon in the eyes of foreigners, and good at mathematics is not Chinese people.

However...

At this moment,

The Department of Mathematics at Beijing University is in big trouble, almost everyone in the department is trapped inside, and this problem happened only five minutes ago... Prof. Yaying Zhang is a professor in the Department of Mathematics at Beijing University and an academician of the Chinese Academy of Sciences.

He serves as the director of the Mathematical Development Laboratory of the International Mathematical Research Institute, the director of the Mathematical Association, the editor-in-chief of seven top journals at home and abroad, and has made contact contributions to the Riemannian manifold and Z-function. He is the limit of the field of mathematics in China.

Nothing was supposed to happen, but... Zhang Yaying received a phone call, which was from Xiao Sun, the head coach of the national team in charge of the training mathematics competition, and Associate Professor Sun explained the current problems to Zhang Yaying.

"Academician Zhang..."

"We can't even read this question... It seems to be a physical phenomenon, but it needs to be expressed in non-Euclidean geometry. Associate Professor Sun smiled bitterly: "That's right... Academician Xu Mang was in our training base, and it was he who came up with this problem and asked us to solve it within four hours, and asked anyone to help at will. ”

"Xu Mang?"

"Yes... He was an advisor to the national team for this mathematics competition. Zhang Yaying said helplessly: "What is the problem, you send me a photo, and I will show you... Is it really that difficult? I can't even read it? It's a bit of an exaggeration. ”

"No, no, no!"

"Academician Zhang... Academician Xu Mang is not an ordinary person!" Associate Professor Sun said seriously: "You think he won the Nobel Prize in Physics at such a young age, and I think this year's Nobel Prize in Physics should also be him, after John Bardeen and Fred Sanger, the third person to win this honor in the same field in a row." ”

"It can be seen how powerful he is, and his research results are based on theory, relying on mathematical calculations..."Associate Professor Sun explained: "It can be seen how powerful Academician Xu Mang's mathematics is, but... I asked him why he didn't study mathematics. ”

“...”

"Everyone knows that he doesn't like mathematics and is forced to study mathematics just because theoretical physics requires it. Zhang Yaying smiled: "When I first heard this kind of words, I was quite angry... Now that I think about it, it's a bit of a stretch. ”

"Actually..."

"There are deeper reasons. Associate Professor Sun said: "According to Academician Xu Mang's explanation, it was all because his wife was holding a kitchen knife and putting it on his neck... Had to participate in the so-called competition with him, but was forced to learn mathematics. ”

“...”

"It's... Forget it. Zhang Yaying hurriedly said: "Send your question over, and I'll study it." ”

Hang up the phone,

In less than thirty seconds,

Zhang Yaying received an email with a picture attached, but she glanced at it for a while, and she didn't find it difficult, but when she officially entered the solution process, she found how hasty the previous glance was.

This question...

It's not easy!

It's not just what it seems, and there's a lot to consider... In short, it is to describe physical phenomena as precise mathematical equations.

"This..."

"Isn't this too much for college students?" Zhang Yaying frowned, full of doubts about this problem, its difficulty far exceeded the scope that those contestants could solve, and it was more inclined to practical application.

But...

Since Xu Mang said that he could find anyone to solve it, is this challenging the Department of Mathematics of Beijing University?

Time

Zhang Yaying ignited a fighting spirit, he hadn't learned from others for a long time, and when he was studying, his favorite thing was to find someone to learn, and now that he is in this position, he doesn't even have the opportunity to learn, but Xu Mang gave him such an opportunity.

soon

The flame of this fighting spirit is a little dim,

It's so hard...

"Hello?"

"Lao Yi!"

"I have a problem here that physics is now described as a mathematical equation, let's solve it together!" Zhang Yaying said: "You can help me see what kind of physical phenomenon this is, it seems to be an extreme space-time curve description problem." ”

"Huh?"

"You've studied physics?" said with a smile, "Show me!"

moment

This person named Lao Yi called Zhang Yaying back, and his tone was quite serious.

"Lao Zhang!"

"Who are you helping solve this problem?" Lao Yi asked, "This problem is not ordinary... From the point of view of understanding alone, it involves the concept of four-dimensional space-time... And there's a decent one... This... The other party is not an ordinary person, is he?"

“...”

"It's Xu Mang. ”

"He was at the math competition training base, and then he gave the contestants such a problem, solved it in four hours, and at the same time asked anyone to help. Zhang Yaying said helplessly: "I think this is challenging us." ”

"Him?"

"He uses this problem for your players to solve?" Lao Yi said confusedly, "This is obviously aimed at your math department!"

"In that case..."

"Then I can't help even more!" Lao Yi showed a smile: "But I can't solve it, you can figure it out yourself, this is completely out of physics, it is a pure mathematical problem, very pure... So pure that no knowledge of physics is required. ”

Hang up the phone,

Zhang Yaying fell into silence, if he was given a few days, he might be able to solve it, but it was only four hours, so harsh that he couldn't speak, which was very unfair... Unless the equation for this problem is extremely simple.

Is it possible?

The problem given by Xu Mang can't be addition, subtraction, multiplication and division.

soon

Zhang Yaying found several other professors in the Department of Mathematics to study this problem together, but after half an hour, she came to the conclusion that it could not be completed in a short time, at least more than two weeks, and even needed to use a computer.

"Academician Xu Mang has a problem for our mathematics department!" a professor sighed: "He has wanted to do this for a long time, right?"

"He..."

"It's hard to say... Although there is no intersection, it is quite strange to hear from other people. Another professor said: "He seems to be easy-going, but in fact he is very stubborn and has a bad temper, and I heard that he has refused many preferential policies for him." ”

"He has the capital to refuse. Zhang Yaying opened his mouth and said: "He won the Nobel Prize in Natural Sciences at such a young age, and it is also the first natural science prize in our country, plus his age... I can't see his height yet, because it's just the beginning. ”

"That's it!"

"Let's continue!" Zhang Yaying said solemnly: "Our mathematics department of Beijing University is the first in the country, and we can't be defeated by a person who is engaged in physics. ”

Then

I don't know who leaked this problem, the entire students of the mathematics department have fallen into a crazy stage for this problem, after all, it was proposed by Xu Mang, if anyone can solve it, then this person will definitely stand out in the mathematics department where the masters are like clouds.

Many people have taken this opportunity as a stepping stone to their success, but unfortunately... They overestimated their own strength, and at the same time underestimated Xu Mang's slut attributes, and in the face of this temporarily unsolvable problem, many people collapsed.

The former four talents have been far away in the United States, and the current four talents, except for two who have entered the national team of the mathematics competition, the other two are sitting in the library together to solve the mathematical problems provided by Xu Mang.

The combination of these two people has attracted the attention of many students, although the so-called four talents are a kind of joking name for everyone, but there is no corresponding strength, and even the joke is mixed a lot, these four people almost represent the highest knowledge of the Department of Mathematics of Beijing University.

But...

The two of them are already desperate at the training base, and the other two are not much better, and there is no solution to the hard work, although they understand the physical phenomenon, but... Will not describe.

On this day,

The Department of Mathematics at Kyoto University experienced four hours of the darkest, and no one knew what to do next.

And at Fuda,

Xu Mang's alma mater,

As the second largest in the country, the Department of Mathematics of Fuda University performed mediocre, and when they knew that Xu Mang provided such a problem, almost no one would not think about solving him, and the legend of Xu Mang was still circulating in the school.

Director Ouyang Fei looked at a question on his computer screen, with a helpless smile on his face. It's too messy, what the hell is he thinking?

On this day,

These four hours,

Everyone is thinking about a question.

How to solve it?

......