At night, the breeze brings coolness.

Across the West Coast, in the White House, a certain president with a cool haircut was staring sharply at the CIA director in front of him.

"Rubbish! After investigating for so long, activating so many resources, and spending so much money, you didn't find anything! ”

"So far, I don't know anything about the details except that the other party has started a project related to nuclear energy, waste, what a waste!"

The CIA director defended innocently: "We can't be blamed for this. ”

"In the past few years, many of the shadows that we planted in that country have been cleared, and now it is clear that we have no access to those core secrets."

"But what we can say for sure now is that Professor Xu played a key role in this nuclear energy project, or that he guided this nuclear energy project."

"In addition, through our investigation, we also found that Professor Xu is conducting research on lithium batteries, he has acquired a materials research institute, and has applied for a patent for an artificial SEI film in countries around the world that are protected by international patents."

"And this patent is used to solve the problem of lithium dendrites in lithium batteries."

"Of course, there are many patents of this type in various countries, and we don't know if this patent can solve the lithium dendrite problem."

Hearing this, the president, sitting across from him, asked, "What is the probability of a possible solution?" ”

As a businessman and politician, he has a certain understanding of lithium batteries, although he does not know a lot, and he is not as good as professionals, but he has long invested in various businesses to let him know that the biggest problem of lithium batteries is the problem of lithium dendrites.

If this problem can be solved, the prospect of lithium batteries will be quite broad.

The director of the CIA shrugged his shoulders and said, "It is difficult to know whether the other party has solved the lithium dendrite problem with a single patent application document, and it is difficult to determine this kind of before the other party publishes it, or before the sample is obtained." “

"According to the survey, this probability is not high, not even one percent. The laboratory that Professor Xu acquired only had more than 10 million yuan, which is about 2 million when converted into rice gold. ”

"A laboratory of this level will basically only have about ten researchers, and they will survive on a few patents. It is almost impossible to solve the lithium dendrite problem. ”

"You must know that there are more than three-digit or even four-digit companies or research institutes around the world every year, and laboratories are studying lithium dendrites, including our Albert Electric, which invests hundreds of millions of meters every year, but there has not been much progress so far."

】

The golden-haired president pondered for a moment, and relaxed a little: "It's basically impossible to say that?" ”

The director of the CIA nodded: "Judging from the survey data, this is indeed the case. ”

Nodding, the president with a super cool hairstyle continued: "Hurry up and investigate, I want to know what the nuclear energy experiment of the other country is studying!" ”

"In addition, if the media is allowed to publicize the news that the other side has violated international conventions and is studying the proliferation of nuclear weapons, etc., and at the same time follow up on the diplomatic side......

........

The arrangement of the Atlantic coast, the confrontation between the two great powers, Xu Chuan, who had already fallen asleep, naturally did not know.

After a quiet night, he made a cup of coffee and a textbook of "Linear Algebra and Spatial Analytic Geometry" on his desk.

This is what I will be talking about in class this afternoon, and although he is familiar with algebraic geometry, as a teacher, there is nothing wrong with preparing for class.

It didn't take him much time, and for this kind of basic book, a simple flip through it was enough.

And for mathematics, the more basic the knowledge, the more important it is.

The morning passed quickly, and after ordering a takeout and having a simple lunch, Xu Chuan came to NTU with the teaching materials.

The venue of the class was changed from the West Building to the No. 1 public classroom in the Shaw Building, which is the largest public classroom on the Xianlin Campus of NTU, with a capacity of more than 500 people.

For the most part, it's mostly a dissatisfying place.

But today, the entire No. 1 public classroom is not only empty seats, not only are the seats full, but even the staircase corridors of the public classrooms are full of people.

Not to mention that the entire classroom was packed, there were quite a few students standing in the corridor outside the classroom.

Although not all of the students who came here had taken algebra geometry, and even many of them did not major in mathematics, many students who had not enrolled in this course also sat here with backpacks.

It's legendary.

Ever since the imo and IPO races, that man has been breaking world records and making new history.

When he was standing here as a professor now, everyone was curious to see what kind of math lesson he would bring to them.

Of course, before the formal class, everyone was discussing whether Xu Chuan would really come.

"Did you think Kawajin would really come to teach us?"

"It should be true, after all, Nanda has confirmed it on its official website."

But this is a Nobel Prize and a Fields Medal winner, and he will come to teach undergraduates? Maybe it's just a name, and it's his students who are in class? ”

"Impossible, doesn't this play tricks on everyone? Kawajin probably wouldn't do such a thing. ”

"Who knows."

"Nope! It must be Kawajin who is teaching, and I am confident. ”

"Make a bet, I'll bet that the god of Sichuan will come for five cents!"

"I'll press a tea egg!"

"I'll press a commemorative version of Furukawa Yinori!"

........

When Xu Chuan came to the No. 1 public classroom in the Shaw Building, even though he had experienced a lot of big scenes, he was also frightened by the scene in front of him.

In the huge public classroom, there are crowds of students, and even lecturers and professors are crowded together, just like the morning rush hour of the subway in a small island country.

If the air circulation is not turned on, Xu Chuan even doubts that the air in this classroom will be enough for so many people.

Seeing him appear in the classroom, the crowd immediately stirred.

"It's coming, it's coming, Kawajin, he's really here!"

"One hour by high-speed rail, two hours by bus! It's worth it to be able to witness the Kawajin once! ”

"The god of Sichuan is awesome! They actually came to teach us. ”

"Being able to listen to the lecture of the Nobel Prize + Philippine Prize elder once, it is worth it in this life!"

"Woo woo woo, I envy the students of NTU, they can listen to it often in the future."

.........

In the classroom, with the appearance of Xu Chuan, the crowd immediately cheered.

Many students just held up their mobile phones and started to snap pictures, and some forgot to turn off the flash.

Xu Chuan smiled and said, "I know everyone is quite interested in me, but I didn't expect so many people to come today, and even I saw the dean of our number academy sitting in the crowd." ”

Shrugging his shoulders, he continued: "It may be that I haven't started the class for too long, and the school leader personally supervised me in the first class. After all, since taking up the position of professor in the second half of last year, it is indeed a bit incompetent to start the first class today. ”

As he spoke, his gaze fell to a corner of the lecture hall, where Zhou Hai, Chang Ming, Rong Zhizhuan, and other NTU professors and leaders from the School of Mathematics gathered together.

Noticing Xu Chuan's gaze, several people smiled and nodded to say hello.

Xu Chuan teased the atmosphere for a moment and continued: "Today's course is based on the textbook of linear algebra and spatial analytic geometry. ”

"Because there are students from undergraduate to graduate students today, the content of the lecture is mainly basic, and some students may wonder why I have such a fairly basic course."

"For this question, if you listen carefully in the next class, I think you should have something to gain."

"Okay, let's start the class, I think you have already previewed it yesterday, so now open the textbook "Linear Algebra and Spatial Analytic Geometry", let's start with the system of linear equations."

"A system of linear equations is a system of equations in which each equation is one-dimensional with respect to an unknown quantity (e.g., a system of two-element 1st order equations). The study of systems of linear equations in our country was at least 1,500 years ahead of the rest of the world. In the equation chapter of the Nine Chapters of Arithmetic at the beginning of the Common Era, there is a study of the system of linear equations. If you are interested, you can check it out. ”

"Linear equations have a wide range of applications, and the well-known linear programming problem is the discussion of linear equations with certain constraints on the solution, which is ..........widely used in geometry, algebra, etc."

.......

It was not for nothing that he served as a professor at Princeton for more than a decade in his last life.

For teaching, Xu Chuan has his own set of methods.

For the mixed group of undergraduates, graduate students, and even doctoral students, from shallow to deep, but the point is not completely deep, and the final depth is maintained at a point where undergraduates have a hazy understanding, and graduate students and doctoral students have self-enlightenment, which is his grasp of teaching knowledge.

The hour-long open class passed quickly, Xu Chuan explained, looked at the students in the classroom who were still struggling to write, and put down the chalk in his hand.

"That's all for today's lesson."

For today's class, NTU has specially arranged a two-sided projector in this public classroom, so that students in the back row can see the blackboard and lecture content in front more clearly.

Hearing the voice, the students sitting in the classroom, especially the undergraduates, finally breathed a sigh of relief.

Although university professors are almost the same, turning a book is faster than turning a face, but it is the first time they have encountered a textbook that has turned nearly one-third of a textbook in one class.

Starting from the system of linear equations, to the determinant and inverse matrix of the square, to the matrix and its elementary transformation, the geometric space, the n-dimensional vector and the system of linear equations......

At the end of the lesson, these undergraduates felt that their minds were already filled with knowledge.

But what made it even more amazing to them was that despite all the things that the man on the podium had taught, they didn't get dizzy to accept the feeling of incompetence.

Although many people began to gradually lose track of the rhythm in the middle and late stages, sometimes Xu Chuan's words made them suddenly realize, as if this was the same as the previous one.

It's like, when the author lays a foreshadowing, the reader doesn't know at first, but when it is connected after dozens of chapters, everyone will suddenly understand that it turns out that this has been mentioned earlier.

"It's no wonder that Kawajin said before the lecture why he talked about these basic things." In the lecture hall, a doctoral student put away his hand to record the last stroke, and couldn't help but sigh:

"I have already finished "Linear Algebra and Spatial Analytic Geometry", and I always thought that I had learned it well, but I didn't expect to listen to this class today, only to find that there are still many things in it that I have not learned."

"Including some technical uses, which I have never learned or thought about before."

The friends around him nodded and agreed: "Compared with Chuan Shen, the professor of algebraic geometry who taught us before is too far behind, and it really can't be compared." ”

The doctoral student smiled and said, "How can this compare?" One is a Filipino Prize + Nobel Prize winner, and the other is just an ordinary university professor. ”

The friend next to him shook his head and said, "No, I'm not talking about this, but the attitude of teaching, skills, and some other things, you know what I mean." ”

The Ph.D. student nodded in agreement and did not speak again.

He also came from an undergraduate degree, and with the current environment, many professors in many colleges and universities are perfunctory when teaching students, and even many of them directly let their assistants or students come.

This phenomenon is experienced by most students who have reached the doctoral level.

And the feeling like Xu Chuan gives them is completely different.

Of course, this may have something to do with the fact that today's class was the first, but in any case, he was very inspired here today.

Those skills, experiences, methods, application and association of knowledge points and other things cannot be learned in books, or even from other professors.

For these graduate students who have already reached the doctoral level, they know very well that these are the most important things.

.........