The top student must be diligent.

Chapter 236 Hello Teacher!
"Students, class is about to begin!"

As Xiao Yi announced the start of the class, many students in the audience stood up at the same time, bowed and shouted, "Hello, teacher!"

Seeing this scene, Xiao Yi was a little amused.

Generally speaking, this part doesn't exist in college classes, but these students actually have such a tacit understanding.

However, facing such a situation, he also bowed slightly to the students and said, "Students, please take a seat."

"Thank you, teacher!"

Afterwards, all the students present sat down. As for those who had no seats, they could only sit on the steps or on the floor.

Xiao Yi felt a sense of emotion, as if he had returned to his primary and secondary school days.

Then he didn't think any more and said, "Okay, this class is a number theory class. According to the original plan, this class is prepared for the students in Hua Luogeng's class."

“Therefore, our courses will be relatively more difficult.”

Xiao Yi did not give in just because there were a bunch of students in the classroom who might not even know what number theory was. After all, he was mainly responsible for the students in Hua Luogeng's class.

We must not fall behind in the class progress.

"Then let's get to the point."

"Students in Hua Luogeng's class, I think you all have a certain foundation in number theory. I believe you all have a certain understanding of elementary number theory. So, in this class, I will start with a point that you may be more interested in."

Xiao Yi turned around and wrote two words on the blackboard.

Prime Numbers

In fact, as the first word appeared, most of the students in the classroom showed quite excited expressions.

Prime numbers, for those who are interested in studying mathematics, who would not be interested?

Moreover, the teacher in front of them in particular was a mathematical master who had successively solved the two major prime number conjectures, the twin prime conjecture and the Goldbach conjecture.

What will this person say about prime numbers?
“Number theory is a mathematical theory that studies the properties of integers. Therefore, in English, number theory is directly translated as number-theory. It is also considered the purest mathematics in the entire field of mathematics.”

"As Gauss said: Mathematics is the queen of sciences, and number theory is the queen of mathematics."

"And if we observe all integers, we will find that there is a class of integers that have very peculiar properties. They are prime numbers, also called prime numbers."

"Their peculiar property is that they can only be divided by 1 and themselves."

"So, it is precisely because of this peculiar property that mathematicians have been attracted to study prime numbers for thousands of years."

"Of course, at this time, some students may ask questions."

“What is the significance of studying prime numbers?”

"What help can studying this thing bring to us humans?"

"Of course, if it is modern, then I would like to talk about RSA encryption. RSA encryption uses the principle of prime factor decomposition to achieve encryption. You can go back and study the details."

"But at this point, someone may ask, RSA encryption only appeared with the advent of the computer age, so why did mathematicians study prime numbers when there were no computers, and even before that?"

"In fact, before that, people's means of public opinion were very limited. They didn't have computers or mobile phones to play with, and they didn't have the convenient transportation like today to travel around the world."

"So, for those mathematicians hundreds or thousands of years ago, most of the reasons they studied mathematics were to kill time."

"So, most of those mathematicians are also wealthy aristocrats, because they have enough time to spend on this kind of thing."

"As for how the research results can help mankind, that is not something they need to consider."

"That is why studying number theory and prime numbers has become a very good choice for these nobles."

"Well, having said that, I need to explain to you that in the process of learning, don't ask what help studying number theory or prime numbers can provide to mankind."

"In fact, when studying theoretical mathematics, don't ask how much help these things can bring to human research."

"Such a question is meaningless in mathematics."

"Just focus on the theory. As for how much help this mathematical theory can provide in the application field in the end, that is what scholars in the application field need to worry about."

All the students present nodded, especially those in Hua Luogeng's class.

Students who come to Hua Luogeng's class are naturally determined to become pure mathematicians, although there is a high probability that many of them will become "rebels" in the future and choose to pursue the path of applied mathematics.

However, for now, their ideal is to become a high-end pure mathematician.

"Well, let's get back to the topic of prime numbers."

"There are an infinite number of prime numbers. This is a result that can be obtained through rigorous proof. The earliest proof was given by Euclid in Proposition 20 of Book of Geometry Elements, using a proof by contradiction."

"Is there any student who can give a proof by contradiction?"

Xiao Yi asked.

Quite a lot of people immediately raised their hands.

This is a very classic proof in itself, so many students know it, and this is no exception.

Xiao Yi quickly picked a student.

The student went up to the podium and began to write the process fluently on the blackboard.

"To prove it by contradiction, we must first assume that prime numbers are finite. So, let's assume that all prime numbers are p1, p2, ..., pn."

"Next, we set N = p1*p2*…*pn+1."

"Obviously, N is not divisible by any of p1, p2, ..., pn."

"Then, this means that either N itself is a larger prime number, which means that among the original finite prime numbers, we have found a larger prime number, which contradicts the hypothesis; and if N is not a prime number, then it means that it can be divided by a larger prime number, which means that there is a new prime number, which also contradicts the hypothesis."

"In this way, we can prove that there are infinitely many prime numbers."

Xiao Yi smiled and nodded, saying, "Yes, it's correct."

Most of the students in the audience nodded. Basically, any student from the School of Mathematics could understand this proof.

Of course, it is inevitable that people from other majors will come to join in the fun, so some people also show puzzled expressions, such as why after multiplying a finite number of prime numbers and then adding one, they cannot be divided by these prime numbers, and why if N is not a prime number, it means that it can be divided by a larger prime number?

However, Xiao Yi did not explain further about this question, which most high school students would understand.

"Very good, now we have figured out the infinity of prime numbers, so the next question is, how do we determine whether a number is prime?"

"Especially when we're dealing with a really big number," he said. "It becomes really hard to determine if it's prime."

"Then at this time, we can use the sieving method."

"The sieve method is a very important method in the study of number theory. It can help us quickly determine prime numbers or the prime factors of a large number."

Xiao Yi wrote [Sieving Method] on the blackboard again.

The study of number theory is inseparable from this knowledge.

Of course, there are many things involved in number theory, but for now, Xiao Yi plans to start with prime numbers and sieve method.

After all, who in the world today does not recognize that he is the most powerful master of sieving?
The students in front of him also knew the same thing, so, because of this, when they heard Xiao Yi talk about the sieving method, they showed even more interest.

As a top mathematician, he himself is able to arouse the interest of these students, and interest is what Xiao Yi mainly wants to impart to these undergraduates.

His graduate students have basically developed a great interest in their majors, so he can train them from a more professional perspective, but for undergraduates, the most important thing is to keep them interested in mathematics.

Therefore, Xiao Yi then focused on guiding these students to study number theory from the perspective of interest.

Mixed in with it are the twin prime conjecture or the Goldbach conjecture that he once proved.

Just the sentence "When I proved the twin primes/Goldbach conjecture, I borrowed this step..." is enough to arouse all the interest and attention in learning anything.

And don't forget that he is also known as the "most popular paper author" in the mathematics community. The steps of the papers he wrote are always very detailed, so much so that many people in the mathematics community highly praise his papers.

Naturally, he brought this fine tradition into the classroom.

As long as students can maintain their attention, they can basically understand his explanation of concepts or methods.

In this way, time passed quietly.

The first class ended before many students had time to react, making them feel as if the class had only started a short while ago.

The second class was the same situation. The 45-minute class passed by without us noticing.

As the bell rang, Xiao Yi did not delay the class at all. He pointed to the two exercises left on the blackboard and said, "Then after we go back, everyone should try to solve these two sieving exercises and review today's course content. See you next week."

"get out of class is over."

After Xiao Yi finished speaking, he was ready to leave.

But what he didn’t expect was that the students in the audience stood up in unison, bowed to him and shouted, “Thank you for your hard work, teacher!”

Xiao Yi had no choice but to come back and bowed, saying, "Thank you for your hard work, classmates."

Then he was able to leave.

When the students in the audience saw Xiao Yi leave, they immediately started talking.

"I feel that Xiao Shen's lectures are very good!"

"Yeah! It's been a long time since I felt that a 45-minute class could pass so quickly! The last time I felt this way was when I was in junior high school."

"IM about the same."

A bunch of students sighed.

I felt that the classes were too long, mainly because I couldn't concentrate and listen.

The reason why they feel that the class is over so quickly is that they are so interested in the class that they don't even notice the passage of time.

This is immersive learning, which naturally leads to rapid absorption of knowledge.

They couldn't help but recall what Xiao Yi said at the beginning, that it was his first time teaching the class, so he couldn't guarantee whether the class would go well.

Looking back now...it was really too modest!

Of course, not everyone has such an experience. Those students from other majors who came simply to join in the fun naturally felt uncomfortable. Considering Xiao Yi's opening remarks, they finally decided not to come to the next class. They could not grasp mathematics.

……

The news spread quickly. The fact that Xiao Yi was teaching had attracted quite a lot of attention, so quite a lot of people were also paying attention to the quality of his classes.

As the news spread, and some students recorded the entire class and shared it online, people couldn't help but wonder, how come some people are not only good at academics, but also good at teaching?
Is there no limit to genius?
As for those students who were persuaded to leave by Xiao Yi at the beginning, they all beat their chests and stamped their feet, thinking they had been fooled!

He is such a good lecturer, but he actually lied to them and said it was his first class. Is it still a question whether the class is good or not?

For a moment, everyone expressed that they must arrive early for Xiao Yi's next class.

However, Xiao Yi has already communicated with the school about this matter, hoping to impose restrictions on these students who are not majoring in mathematics. First of all, it is necessary to ensure that all students in Hua Luogeng's class can enter the classroom and have seats, and secondly, it is necessary to ensure that all people attending the class are majoring in mathematics.

The school naturally agreed and said it would come up with a plan as soon as possible, and the School of Mathematics also actively cooperated.

Just kidding, it would be fine if Xiao Yi’s lectures were average, but now that they are so good, of course they would prefer to let students from the School of Mathematics attend them.

This is the college’s resource!

People from the School of Physics also shouted, Xiao Yi is also a professor in their school of physics!
You should also take some physics classes!

Of course, the School of Materials and the School of Chemistry also joined in the fun.

For a time, the issue of Xiao Yi attending classes caused controversy in the school.

Xiao Yi had no choice but to agree to give these colleges a few open classes when the time comes.

No matter how much they quarreled later, Xiao Yi would not care.

He has more important things to do.
EAST-S, the Super Eastern Super Torus, jointly developed by the Institute of Plasma Physics and the Science Island Laboratory, has been officially launched.

That’s right, the final name was determined to be EAST-S.

After Xiao Yi left that day, the remaining three people couldn't think of a better name for this open plan, so in the end, they decided to use the name that Zhao Zhanyou first mentioned.

When Xiao Yi learned about this, although he did not say a word, Zhao Zhanyou and Li Jiangan always felt that Xiao Yi looked at them with contempt. As for Director Liu, he had already gone to Beijing, so he avoided being ridiculed by Xiao Yi's eyes.

Of course, the name of the secret plan, Creating the Sun, has unsurprisingly received unanimous praise, and in order to cater to the four-character myths of Kuafu chasing the sun and Houyi shooting the sun, the full name of the plan to create the sun is called: Mortals Creating the Sun. However, in normal times, it is simply called Creating the Sun.

In this way, this plan, which was ostensibly just to build a new tokamak experimental device, was launched.

The construction site of the sun-making device is located in the northern suburbs of Luyang District.

Of course, if you look closely, you can find that this location is quite close to the nearest power plant.

(End of this chapter)