After pulling several people to ask for directions in a row, all of them saying that they had not seen Perelman on this street, Xu Chuan was also a little confused.

Perelman, do you really live here now?

I heard that he moved once, the address he gave in the mailbox should not be the previous address, right?

But fortunately, Tao Zhexuan confirmed that he didn't live here before, and it seems that this reclusive weirdo is really completely reclusive.

Shaking his head, Xu Chuan walked forward, grabbed a middle-aged man, continued to consult, handed over the photo in his hand, and after the middle-aged man looked at it, he said, "Professor Perelman? ”

Hearing that the other party recognized him, Xu Chuan's spirit was shocked, and he said quickly: "Do you know where he lives?" ”

The middle-aged man in a thin coat looked at the photo in his hand again, and after thinking for a while, he suddenly stared at Xu Chuan twice, and asked in a suspicious tone:

"You are. Professor Xu Chuanxu? ”

Xu Chuan glanced at him, and after confirming that he really didn't know the other party, he nodded and said, "I am, may I ask who you are?" ”

I have to say that it is still good for people to be handsome.

He asked for a long time with Perelman's 'scrawled' photo, and he didn't know many people, but now he was recognized.

After confirming that the figure in front of him was really Professor Xu, the middle-aged man excitedly stretched out his hands: "Hello Professor Xu, my name is Kelvin Yves, I am a professor of mathematics at St. Petersburg State University, I didn't expect to see you here." ”

"Hello, Professor Kelvin."

Listening to the self-introduction of the man in front of him, Xu Chuan shook hands with him with some surprise, but he didn't expect to meet a mathematics professor at St. Petersburg University in such a remote suburb.

The mathematical strength of Tsarist Russia is still very strong, and the mathematical strength of St. Petersburg State University, when converted to China, is almost the same level as Shuimu Peking University.

"Professor Xu, Professor Schultz, Professor Tao, are you going to go to Perelman?" After a brief greeting to the three of them, Kelvin Yves asked with a smile.

Xu Chuan nodded and said, "Do you know where he lives on this street?" ”

Kelvin Yves shook his head and said, "I'm sorry, Professor Xu, I've been working here for two years, and I haven't seen Perelman much, let alone where he lives. ”

"But I do know that someone should know where he lives, and needs me to take you to him?"

Xu Chuan: "Is it far from here?" ”

Kelvin Yves laughed, "It's not far, just a little in front of this street." ”

Just as Xu Chuan was about to ask him to bring him over, Zheng Hai, who had been following him like an invisible person, took two steps forward and asked, "May I ask what is the name of the place you said?" Who is he? Where is it? ”

Kelvin Yves glanced at Zheng Hai, then at Xu Chuan, and said with a smile: "Szeklov Institute of Mathematics, Professor Curtis Peris!" ”

Hearing this name, Xu Chuan suddenly reacted.

Curtis Perris, a great expert in probability theory and topology in Tsarist Russia, may not have a very prominent reputation on the outside, but his strength is still very good.

And he also has a very famous mentor - Andrey Kolmogorov!

He is known as the 'Ke Laoxi' in the mathematical world, the founder of modern probability theory, and the all-round talent in the mathematical community in the nineties of the last century, which has influenced the development of the mathematical community in the 21st century.

Its place in modern probability theory is what Grothendieck's place is in algebraic geometry.

"I didn't expect Professor Curtis to be here, but when did the Sczelov Institute of Mathematics move here?" Xu Chuan asked curiously.

The Szeklov Institute of Mathematics is the top mathematical research institute in Tsarist Russia, which was proposed by the mathematician and mechanic "Sczelov" during the former Red Soviet period.

This is a 'red' research institute, and almost all of the scholars in it are from red countries, including China, where many people have done research and exchanges in the last century.

Kelvin Yves grinned, "This is just a branch, based on the Department of Mathematics of St. Petersburg State University, and the headquarters is still in Cosmo. ”

As he spoke, he led a few people towards the Skkelov Institute of Mathematics.

Not very far, just at the end of this street, a red-and-white building with a pre-Red Sioux architectural style comes into view.

Just as the group was about to go in to find someone, an old man in a windbreaker happened to walk out of the building.

"Professor Curtis."

The first to recognize it was naturally Kelvin Yves, who walked up quickly to say hello and introduced: "Professor, Professor Xu Chuan, Professor Tao, Professor Schultz, they are here." ”

Hearing this, Curtis Perris was stunned for a moment, then looked at the few people standing on the side of the road, and after confirming that he was not mistaken, he greeted him with a smile on his face.

"Professor Xu, Professor Tao, Professor Schultz, welcome, welcome to the Sczelov Institute of Mathematics, come here, why don't you say hello to me in advance."

The professor thought that a few people had come to look for him, and greeted him warmly.

Xu Chuan was slightly stunned, knowing that the old gentleman in front of him had misunderstood, but he didn't break the old man's enthusiasm, smiled and greeted him a few words, until the old man warmly invited him in, he was a little embarrassed to speak.

"Professor Curtis, do you know where Professor Perelman lives down this street?"

Curtis was stunned for a moment, then reacted, and understood that the real bulls in front of him were all looking for Perelman.

Smiling, he said, "I know this, but I don't know if he's at home today, do you need me to take you there?" ”

"If you can, you'll be bothered."

"It's okay, I'm going to go out anyway, so I'll take you there."

Curtis smiled and put on his trench coat and led the way towards the street in the distance.

After walking for nearly fifteen minutes, just as they were about to walk out of this small street, an old apartment appeared in front of several people.

"He's living here, but he doesn't really like outsiders coming to disturb him, especially with so many of you, I don't know if you're going to be turned away."

After bringing the person to the door, Curtis said with some disapproval.

Although he lives in the same town as Perelman, he doesn't always meet each other once a year.

He had also come to visit a long time ago to talk about mathematics, but except for one chance to meet someone, the follow-up visits were almost closed.

Xu Chuan shrugged his shoulders and said with a smile: "I hope for the sake of mathematics, I can meet you." ”

As he spoke, he shifted his attention to the old apartment in front of him and looked twice.

In a small apartment, the white paint on the walls is falling down piece by piece, and the wooden windows can clearly show the traces of time.

To be honest, he couldn't imagine that a great mathematician who proved Poincaré's conjecture lived in such a small, old apartment.

I have to say that even he is actually a little incomprehensible.

After all, although he is dedicated to academics, he doesn't mind using academics to make life better for himself and his family.

And Perelman, who can only be said to be an admirable 'ascetic'.

After all, if he needed money, the various bonuses brought by proving Poincaré's conjecture would be enough for him and his family to live well for the rest of their lives.

Although he was not sure if Perelman was home now, Xu Chuan stepped forward and knocked on the door.

After waiting for a while, the door to the apartment 'creaked' open.

A tall, burly man with a messy beard and wearing old jeans and a dark shirt appeared in front of him.

His gaze swept over the crowd standing at the door, and finally landed on Xu Chuan's body, with a hesitant expression on his face, he was the first to speak:

"Are you Xu Chuan?"

Xu Chuan nodded and stretched out his right hand with a smile: "It's a pleasure to meet you, Professor Perelman." ”

Perelman touched it gently, shook his hand briefly, and said, "I'm just a mathematician, not a professor, just call me by my name." ”

"Come in first, standing in the door is not a good place to chat."

With that, he stepped out of the way and let in the few people standing in the doorway.

The entrance to the small apartment is the living room, the living room is not big, the furniture is also very simple, there is no coffee table, only a 7-shaped sofa, very small, only able to sit three or four people is full.

This is so that several people squeezed in and some people couldn't find a place to land.

Perelman didn't care, he walked into the room casually and found two cheap plastic stools, and handed them to Kelvin Yves and Zheng Hai, who were not yet seated.

Zheng Hai didn't answer the stool, he glanced at the messy room, and silently walked to the corner of the staircase, and directly became an invisible person.

Perelman glanced at Zheng Hai and ignored him when he saw him standing there without moving.

"Do you want something to drink? But I only have coffee, black tea and water here. Perelman asked casually, not caring about his own poverty.

Xu Chuan glanced at Perelman, who had messy hair, and said, "Just have a glass of water." ”

I heard that Perelman's living expenses are less than 50 meters a week, or his mother's retirement allowance. It can only be said that this great mathematician dedicated everything he had to mathematics.

On the side, several other people also nodded in agreement.

"Me too."

"Just like Professor Xu."

Perelman nodded, got up and walked to the water dispenser, took a few disposable cups from the side, and poured them for a lifetime, including Zheng Hai, who was standing in the corner without movement, and handed over a cup with some surprise.

From this point of view, it's not that he can't socialize, he just doesn't want to socialize.

Stuffing the plastic stool in his hand directly under his buttocks, Perelman pinched the water glass in his hand and took a sip, looked at Tao Zhexuan and Schultz, and ignored Curtis and Kelvin on the side.

"Why are you here together?"

Tao Zhexuan smiled and said, "This year's International Congress of Mathematicians is being held in St. Petersburg, let's stop by to see old friends, aren't you welcome?" ”

Perelman said expressionlessly: "If you come with math, I'm welcome. If not, it doesn't make much sense. ”

Hearing this, Tao Zhexuan couldn't help but shake his head gently.

Although he admired Perelman's research in mathematics, if he wanted to be like the other party, he probably couldn't do anything but mathematics.

I don't think anyone who is sitting here today can do it except Perelman.

Seeing that Tao Zhexuan did not come with a mathematical problem, Perelman quickly took his eyes off him.

Without paying any attention to the others, he looked directly at Xu Chuan, and after staring at him up and down for a while, he suddenly said: "I have read all your mathematical papers, starting with the Weil-Berry conjecture and ending with the Yang-Mills existential and mass gap problem, which are quite exciting. But if I were to evaluate it, the best one is the proof of the existence of the solution of the NS equation. ”

"It was perfect, so perfect that it was stunning. Using the Ricci manifold to unfold the fluid topology, construct the geometry, change it from an irregular manifold to a regular manifold Honestly, I still don't understand how you came up with this construction method, it shouldn't exist in this world, it's like it comes from the void."

As if talking to himself, and as if asking Xu Chuan how he did it, Perelman muttered and narrated, and his brown-green eyes looked at Xu Chuan opposite for a moment.

For Perelman, who solved the Poincaré conjecture, topology and manifolds can be said to be his natal domain.

When Xu Chuan studied the NS equation, the way in which the fluid topology was developed through the Ricci manifold and then the geometry was undoubtedly the most interesting way for him.

But as he himself said, he couldn't understand how the other party came up with this method.

It's so subtle, it's perfect.

It is so perfect that the whole mathematical tool is like coming from nothing, or a gift from God to mankind.

PS: There will be a monthly pass in the afternoon, and I will start to resume the double watch, so I've kept everyone waiting, sorry.