From university academician to chief academician

After ending his communication with Gao Fei, Ye Fei looked at other people's posts.

By the evening, the task progress reached 60%.

Ye Fei thought to himself: "Is my task setting simple? The task progress reached 60% in half a day."

"How about setting up the mission to enter SCI Area 1?"

"Fuck..." Ye Fei was startled by this terrible thought. What was he thinking, entering the SCI Zone 1?

With my current abilities, I will have to go through a long period of study before entering the second area.

Zhuang Nan took his hand away from the computer and said with a gossipy face: "Ye Fei, do you know why your instructor allowed your paper to enter the CSCDA area?"

"Why?"

"Do you still remember the mentor's rival, Professor Li Jiguo? I heard that one of his first-year graduate students had a paper entered into the CSCDA area not long ago."

Professor Li Jiguo is also from the Department of Mathematics. He and Professor Lu Yishan once competed for provincial scientific research funds. They both wanted to do scientific research and needed scientific research funds.

However, Professor Li Jiguo failed in the competition, which led to the delay of Professor Li Jiguo's scientific research. Later, he competed with Professor Lu Yishan for the full professorship.

Because of the delay in scientific research, his scientific research had not been completed at that time, which led to the failure of the competition for full professorship.

After this back and forth, the two of them formed a feud.

"In addition, you are the only one among us who has passed the graduate school, and the instructor usually has high requirements for you. Naturally, this glorious task is handed over to you." Zhuang Nan said with a smile.

"I asked why my supervisor asked me to enter Area A for my thesis!" Ye Fei shook his head.

Ye Fei did not doubt Zhuang Nan's intelligence. Zhuang Nan was known as an intelligence expert. He could find out everything in the school in half a day.

"Isn't it sad?" Zhuang Nan smiled and said, "It was an unreasonable disaster."

"That's not the case." Ye Fei said: "Area A is just Area A. It's not like we can't get in."

Zhou Lin and Xu Tian walked in together with smiles on their faces and talked about their girlfriends.

Zhou Lin said: "Women, you can't spend money just by beckoning."

"Tch..." Xu Tian said: "Are those women interested in you? Are they interested in your money? You still have to be careful when making a girlfriend. Women care about details."

Zhou Lin said contemptuously: "Are you trying to get away with your heart? You are trying to get rid of your kidneys."

Ye Fei and Zhuang Nan looked at the two people who walked in together and cursed in their hearts: "Two scumbags, I don't know how many girlfriends they have."

Ye Fei is very strange sometimes. He may be pretty good-looking, but he is still a novice, 100% pure.

In terms of appearance, he is the best in the whole dormitory.

Forget it, Zhou Lin is a second-generation rich man who is as good at love as a duck in water.

But Xu Tian, ​​from an ordinary family, is neither tall nor handsome, and a bit dark, but with a mouth that can talk dead people alive, his ex-girlfriend has a row.

In the end, Ye Fei concluded that it was no wonder that there were so few girls majoring in science. Girls were so irrational that they would not be able to find anything after being sweet-talked.

The next day, more than thirty people were in class.

A professor in his forties was speaking on the podium about the expandability of linear functionals on Banach spaces in the Hahn-Banach theorem in functional analysis.

This also belongs to set theory and is the axiom of choice among the five axioms of set theory.

If the continuum hypothesis is proven, then there are six axioms.

This is a very profound knowledge.

Although everyone has previewed in advance, no one in the class can understand 100%, so everyone is painfully writing down what the professor said on the computer.

Wait until after class to review. If you still can't learn it, you can find information to study on your own, or ask your instructor, or ask a senior who has already learned it.

There are more than thirty people in this class, but they are not graduate students under one supervisor, but graduate students under multiple supervisors gathered together for class.

There are some big differences between graduate students and undergraduate students.

Graduate students no longer refer to such-and-such class, but to follow such-and-such tutor.

A tutor may tutor one or two graduate students every year, and may tutor three or four graduate students each year. In three years, he can tutor three to 12 graduate students.

The four of them in Ye Fei's dormitory were working with the same instructor.

Zhuang Nan, who was sitting next to Ye Fei, asked quietly: "Ye Fei, look at you listening so carefully, how much do you understand?"

"I understand everything." Ye Fei said without looking back.

In math class, you cannot talk casually or lower your head. You may say something, lower your head, and then raise your head to listen to the teacher's lecture, and you will be dumbfounded.

What is the teacher saying?

How to solve this problem?

Fuck...I don't understand.

Zhuang Nan curled his lips and said, "Just blow it!"

Although Ye Fei came from Baoyan, they have been together for nearly a year, so he still knows what level Ye Fei is.

Postgraduate studies are only good at the undergraduate level, but not necessarily at the postgraduate level.

And can you understand all of such a difficult course?

A smile appeared on Ye Fei's lips. He might not have understood it before, but with the support of the system, he really understood it.

And the level of understanding is not 66.8%, nor 99.8%, but 100%.

The professor on the podium coughed slightly when he saw Ye Fei talking to Zhuang Nan.

Universities are not as strict as junior high schools and high schools. As long as the impact in class is not significant, professors will turn a blind eye.

But Zhuang Nan didn't seem to notice. He told Zhou Lin and Xu Tian beside him that Ye Fei could understand everything, and both of them looked disbelieving.

The professor saw that Zhuang Nan was still speaking, and everyone in the classroom was listening quietly. He was smiling and talking, which affected all the nearby students. This was unforgivable.

He pointed at Zhuang Nan and said, "This classmate, stand up."

The classroom fell silent for an instant, and everyone looked at Zhuang Nan.

Zhuang Nan looked around blankly and saw everyone looking at him. He knew that what he said had angered the professor, and he felt a little panicked.

He stood up in panic.

The professor asked: "What did you just say? You were so excited."

Zhuang Nan lowered his head and said guiltily: "Professor, I'm sorry."

"Tell me, what did you just say?" the professor said.

"..." Zhuang Nan was silent. It didn't matter if he himself was punished, but it would be bad if the other three roommates were implicated, so he remained silent.

When the professor saw that he was silent, he pointed at Ye Fei and said, "The student on the right is the first one to talk to you. What did you say?"

Ye Fei stood up and said, "Professor, he asked me how much I understood, and I said I understood everything."

"Did you understand everything?" the professor asked in surprise.

He knew the difficulty of this course. Very few first-year graduate students could understand everything. They all reviewed carefully and looked up information after class, and then slowly learned it.

Many people looked at Ye Fei in surprise.

Did you understand everything?

Don't brag, okay?

The professor said funnyly: "Since you said you understood everything, then tell me how to use the Krylov subspace method to solve linear equations."

The professor felt that this was too difficult for a graduate student, and said: "I don't want to ask for the complete solution, just give a general idea."

Ye Feidao: "Professor, can I go up? I can't say it, I have to write it down."

Everyone looked at him in surprise, Brother, you really did it!

It's easy to go up, but hard to come down!

No one believed that Ye Fei could solve the professor's problem.

"Okay!" The professor nodded.

It wasn't that he wanted to embarrass Ye Fei, but Ye Fei said he understood everything, so he wanted to test it.

It just relieves the fatigue of long classes, just use it as entertainment!

It doesn't matter if you can't solve it. It's normal if you can't solve it. If you can solve it, it proves that the student really understands everything.

Ye Fei stepped forward, picked up the chalk, and said to everyone: "If you want to use Krylov subspace to solve linear equations, you can first use Hilbert space to preprocess the Krylov subspace and its convergence."

"Consider linear algebraic systems."

He took the chalk and wrote a set of equations on the blackboard.

【Ax=b】

"..."

"b∈R is a known column vector."

"That's the general idea of ​​what I'm thinking."

"Very good!" The professor nodded with satisfaction: "It seems that you have indeed understood everything, and the idea of ​​​​solving the problem is very correct."

Everyone was surprised. They really understood everything. Don’t be a blind cat and a dead mouse. You just know what the professor said!

Ye Feidao: "Actually, if you want to solve a linear algebra system, you can still solve it like this."

Ye Fei found that the progress of the task had improved a bit since he had just come up to solve the problem.

In this case, let's solve some more problems to improve the progress of the task.

"Do you still have a way?" The professor was shocked.

"Yes!" Ye Fei nodded: "For solving linear algebra systems, you can also use the projection algorithm of the Krylov subspace method."

"Do you still know the projection algorithm?" The professor was surprised.

This method is beyond the scope and he has not taught it in class.

Moreover, the projection algorithm is not something that can be learned in the first year of graduate school. It can only be learned in the third year of graduate school.

"I have read it in a paper before." Ye Feidao: "So I learned it."

"Then you use the projection algorithm to see."

Ye Fei turned around and wrote on the blackboard.

[Suppose the initial solution is x, then the corresponding initial residual is r=b-Ax, we call the formula

K(A,r)=span{r,ArA^2r,.Ar}

…

Here L is another m-latitude subspace, called a constrained subspace. 】

The classroom looked at what Ye Fei wrote with joy and praised: "Very good, very good, completely correct."

"Classmate, what is your name? Which professor is a graduate student?"

There are so many people attending classes, and such classes only happen once every half month, so the professor doesn’t know all the students present.

"My name is Ye Fei, and my mentor is Professor Lu Yishan."

"It turns out you are Professor Lu Yishan's student, no wonder." The professor nodded and said, "Ye Fei, I remember you."

The students below looked at what Ye Fei wrote and were dumbfounded.

Fuck...I can't understand.

When did our basic mathematics major have such an outstanding person?

Aren't you a graduate student?

Are we in graduate school at the same time?

Zhuang Nan and his two roommates looked at each other in surprise, Ye Fei, when did you become so powerful?

"Okay, you can go down now." The professor said, "That classmate should also sit down and stop talking, otherwise I will ask you to stand up."

"You should also learn from the classmate next to you and study hard."

Zhuang Nan was very sad to hear this. Who didn't study hard? I studied hard, but Ye Fei didn't know what happened today, as if he was cheating.

After class, Zhuang Nan and the other three surrounded Ye Fei, looking at him eagerly, and said, "Ye Fei, tell me, did you study secretly?"

"Really not!" Ye Fei shook his head: "I just read the literature that my instructor usually asked me to read. He also recommended you to read it. Who do you blame if you don't read it?"

"Really?" Zhuang Nan and the other three were suspicious, looked at each other, and said to themselves, "No, starting today we will also read the literature recommended by the instructor."

"Let's go quickly!" Ye Fei walked forward: "There are still classes below!"