"Classmates, come to class!"
As Xiao Yi announced the start of class, many students in the audience stood up in unison, then bowed and shouted, "Hello, teacher!"
Seeing this scene, Xiao Yi was dumbfounded.
Generally speaking, this link is not available in university classes, but these students actually have such a tacit understanding.
However, facing this situation, he bowed slightly to these students and said, "Students, please sit down."
"Thank you teacher!"
Afterwards, all the students present sat down. As for those students who had no seats, they could only sit on the steps or the floor.
Xiao Yi felt a burst of emotion in his heart, as if he had returned to his primary and secondary school days.
Then he stopped thinking about it and said, "Okay, this class is a number theory class. According to the original plan, this class is prepared for the students of Hua Loo-Keng Class."
"So our courses will be relatively difficult."
Xiao Yi did not give in because there were a bunch of students in the classroom who might not even know anything about number theory. After all, he was mainly responsible for the students of Hua Loo-Keng Class.
You must not fall behind in terms of class progress.
"Then let's get to the point."
"Hua Loo-Keng Class students, I think you all have a certain foundation in number theory. I believe you have a certain understanding of everything about Elementary Number Theory. So, in this lesson, I will start with the point that everyone may be more interested in."
Xiao Yi turned around and wrote two words on the blackboard.
[Prime number]
In fact, as soon 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 is not interested?
Moreover, especially the teacher in front of them, he has successively won the two masters of prime number conjecture mathematics, Twin Prime Conjecture and Goldbach Conjecture.
What will happen if this person talks about prime numbers?
"Number theory is a mathematical theory that studies the properties of integers. Therefore, in English, number theory is also directly translated as number-theory. It is also considered the purest mathematics in the entire field of mathematics."
"As Gauss said back then: Mathematics is the queen of science, and number theory is the queen of mathematics."
"Looking at all integers, we will find that there is a type of integers with very peculiar properties. They are prime numbers, also called prime numbers."
"Their peculiar property is that they are only divisible 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 classmates may want to ask."
"What is the point of studying prime numbers?"
"What help can studying this thing bring to us humans?"
"Of course, if it were in modern times, then I would say RSA encryption. RSA encryption uses the principle of prime factorization to achieve encryption. You can go back and study the details."
"But at this time, someone may want to ask again. RSA encryption only appeared with the advent of the computer age. So why did mathematicians study prime numbers before computers and earlier?"
"Actually, before this, people's means of public opinion were very limited. They did not have computers or mobile phones to play with, nor were they able to travel around the world with convenient transportation like today."
"So, for mathematicians hundreds of thousands of years ago, most of the reasons they studied mathematics were to kill time."
"So, most of those mathematicians are from 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."
"For this reason, 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 next learning process, 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 studying these things can bring to human research."
"Such questions are meaningless in mathematics."
"Just focus on the theory. As for how much help this mathematical theory can ultimately provide for applications, that is what scholars in the application field need to worry about."
The students present all nodded, especially those students from Hua Loo-Keng Class.
The students who come to Hua Loo-Keng Class naturally aspire 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 tall pure mathematician.
"Then let's return to the topic of prime numbers."
"There are infinite prime numbers. This is a result that can be obtained through rigorous proof. The earliest proof was given by Euclid in Proposition 20 of Volume 9 of "Elements of Geometry", which used a proof by contradiction."
"Is there any classmate who can give this proof by contradiction?"
Xiao Yi asked a question.
Quite a few people raised their hands immediately off the court.
This itself is a very classic proof, so there are many students who know it, and there is no exception.
Xiao Yi quickly clicked on a student.
The student came to the podium and began to write the process smoothly on the blackboard.
"Using proof by contradiction, we must first assume that the prime numbers are finite. Then, we might as well assume that all prime numbers are p1, p2,..., pn."
"Then, we let 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 originally limited number of prime numbers, we have found a larger prime number, which contradicts the hypothesis; and if N is not a prime number, 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 nodded with a smile and said, "Not bad, it's very right."
Most of the students in the audience also nodded. Basically, students from the School of Mathematics can understand this proof.
Of course, it is inevitable that other majors will come to join in the fun, so some people also expressed doubts. For example, why can't a limited number of prime numbers be divisible by these prime numbers after being multiplied by one? Or, for example, why if N is not a prime number, does it mean that it can be divisible by a larger prime number?
However, Xiao Yi did not explain much about this kind of question that high school students would probably understand.
"Very good, now that we have figured out the infinity of prime numbers, the next question becomes, how do we determine whether a number is a prime number?"
"Especially when you're dealing with a particularly large number."
"It's hard to tell whether 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 [Sifting 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 the sieve method.
After all, who in the world doesn't recognize him as the most powerful sifting master today?
The students in front of them also knew it, so, because of this, when they heard Xiao Yi talking about the sieving method, they became even more interested.
As a top mathematician, he can arouse the interest of these students, and interest is what Xiao Yi mainly wants to teach 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, keeping them interested in mathematics is the most important.
Therefore, the following Xiao Yi will focus on guiding these students to learn number theory from the aspect of interest.
Among them are Twin Prime Conjecture or Goldbach Conjecture that he once proved.
Just saying "When I first proved the twin prime number/Goldbach Conjecture, I learned from this step..." is enough to mobilize all the interest and attention in learning.
And don't forget that he is also known as the "most popular paper author" in the mathematics community. The papers he writes have always been very detailed in steps, so that many people in the mathematics community highly praise his papers.
And this fine tradition of his has naturally been brought to 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 could react, making them feel as if the class had just started.
The second class was in the same state. The 45-minute class passed by without even realizing it.
As the bell rang for the end of get out of class, 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 will try to solve these two sieve method exercises and review today's course content. Then we will see you next week."
"Get out of class is over."
Xiao Yi was ready to leave after saying that.
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, bowed, and said, "Thank you for your hard work, classmates."
Then he was able to leave.
When the students in the audience saw Xiao Yi leaving, they immediately started talking.
"I feel that Scholar Xiao's class is very good!"
"Yes! It's been a long time since I felt that a forty-five minute class could pass by so quickly! The last time I felt like this was when I was in junior high school."
"Me too."
A bunch of students sighed with emotion.
I felt that the class was too long, mainly because I couldn't listen carefully and couldn't concentrate.
And they feel like a class is over quickly because they are so interested in the class that they don't even notice the passage of time.
This is immersive learning, which naturally brings about rapid absorption of knowledge.
They couldn't help but recall what Xiao Yi said at the beginning. It was his first time in class, so he couldn't guarantee whether he would do well in class.
Looking at it now... it's so humble!
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 what Xiao Yi said at the beginning, they finally decided not to come to the next class. They couldn't grasp mathematics.
The news spread quickly, and Xiao Yi's class itself attracted a lot of attention, so a lot of people also paid attention to the quality of his class.
As these news spread, and some students on site recorded the entire class process and shared it online, people couldn't help but wonder, how come some people are good at academics and even good at teaching?
Can genius have no limits?
As for the students who were initially persuaded to leave by Xiao Yi, they all beat their chests, thinking they had been fooled!
The lecture was so good, but he actually lied to them and said it was his first time in class. Whether the class was good or not was still a question?
For a while, everyone said that they must arrive early for Xiao Yi's next class.
However, regarding this matter, Xiao Yi has communicated with the school, hoping to impose restrictions on these non-mathematics major students. First, it must ensure that Hua Loo-Keng Class students can enter the classroom and have seats. Secondly, it must ensure that everyone attending the class must be mathematics majors.
The school naturally agreed and would make a plan as soon as possible. Of course, the School of Mathematics also actively cooperated.
Just kidding, Xiao Yi's lectures were just mediocre. Now that they are so good, of course they would rather have students from the School of Mathematics attend them.
These are the resources of the college!
The School of Physics also shouted, Xiao Yi is also a professor in their School of Physics!
You should also take a physics class!
Of course, School of Materials Science and the School of Chemistry also came to join in the fun.
For a time, there was a dispute in the school over Xiao Yi's class.
Xiao Yi had no choice but to agree to give these colleges a few open classes when the time came.
As for how much noise they made later, Xiao Yi wouldn't care about it at all.
He has more important things to do.
EAST-S, Super EAST, jointly developed by Plasma Institute and Science Island Laboratory, has been officially approved.
Yes, in the end, the name was determined to be EAST-S.
After Xiao Yi left that day, the remaining three people really couldn't think of a better name for this explicit plan, so in the end, they decided to use the name Zhao Zhanyou originally mentioned.
When Xiao Yi learned about this, although he didn't say a word, Zhao Zhanyou and Li Jiangan always felt that Xiao Yi looked at them with contempt. As for Director Liu, he had gone to Shangjing a long time ago, so he avoided being laughed at by Xiao Yi's eyes.
Of course, the name of the secret plan, Making the Sun, has received unanimous praise without surprise. In order to cater to the four-character myths such as Kuafu chasing the sun and Hou Yi shooting the sun, the full name of Sun-Making Plan is called: Mortal Sun Creation. However, in normal times, it is simply called making the sun.
In this way, this plan, ostensibly just to build a new tokamak experimental device, was launched.
The construction point of the sun-making device was placed in the northern suburbs of Luyang District.
Of course, if you look carefully, you can find that this location is quite close to the nearest power plant.