At half past eight in the morning, the lecture hall was almost full.

Lu Zhou found a place in the back row and sat down very low-key.

By 8:50 a.m., the lecture hall was full, and some people brought stools from the next classroom and sat in the aisle to listen.

Not even from this school, even people from several colleges and universities next door came to skip classes.

It can be seen that the popularity of this Professor Ren Changming is indeed not small.

At 9:00, the lecture officially began, looking at the old gentleman on the podium, Lu Zhou became more and more familiar, and he always felt that he had a one-sided relationship. But it was so far away, and maybe he had changed his clothes, he really couldn't remember where he had seen it.

The PPT began to show, and the freshman and elementary school girl sitting next to her finally stopped chattering with her roommate on the other side and reached into her bag to get notes and pens.

At this time, she saw Lu Zhou next to her and was suddenly stunned.

After a few more glances, she asked in a low voice, "Classmate, are you Lu Zhou?" ”

Lu Zhou was stunned for a moment and nodded: "Yes." ”

The girl's eyes lit up, and she whispered in a slightly excited tone, "You...... Are you a land boat in the first or third class? ”

"Yes...... Can I help you? ”

"No, it's fine." The elementary school girl quickly shook her head.

It's okay, what are you telling me to do!

Lu Zhou was speechless, opened the small notebook, and began to take notes.

“……”

Lu Zhou: "......"

I don't know if it's his illusion, but I always feel that the two freshmen and girls next to him are secretly looking at him, and they are excitedly whispering to each other, pointing and whispering.

Lu Zhou sighed in his heart.

Is that what it's like to be a celebrity?

Feel......

Not bad?

Fortunately, they didn't talk about it for long, and soon the topic went somewhere else.

Lu Zhou automatically blocked the interference of the outside world and focused his attention on the lecture itself.

It just so happened that Professor Ren had just finished his opening remarks, and he didn't miss a lot of content.

“…… As we all know, prime numbers are natural numbers with only two factors, and you may have memorized the first 100 prime numbers table when you were in junior high school. The twin prime, on the other hand, refers to a pair of prime numbers with a difference of 2, that is, p and p+2 are both prime pairs. For example, 3 and 5, 5 and 7, 11 and 13, 17 and 19, etc. As the number increases, fewer and fewer pairs of twin primes can be observed. ”

"There are 8 pairs of twin primes within 100, and there are only 2 pairs in the range of 501 to 600. As the prime increases, the next prime should be farther and farther away from the previous prime, but a conjecture as famous and important as Goldbach's conjecture asserts that there are infinitely many pairs of primes, which differ only by 2, e.g. 3 and 5, 5 and 7, and even this ......"

Speaking of this, Professor Ren wrote a line of numbers on the blackboard.

[2003663613× 2195000-1 and 2003663613×2195000+1]

Turning around, he smiled and continued.

"There are infinitely many primes with a difference of 2, which is known as the twin prime conjecture."

So far, what Professor Ren has said is some superficial knowledge, and even Lu Zhou, who has not studied the twin prime problem in depth, can easily keep up.

The rest of the freshmen, both math and non-math amateurs, listened attentively with interest.

Soon, though, the lecture began to go deeper.

“…… The twin prime conjecture has always been a difficult problem in the mathematical community. However, just last year, there was a breakthrough in research on this issue. Professor Ren smiled, turned to the next page of the PPT, and continued, "Mr. Zhang Yitang, a Chinese mathematician, proved a weakened form of twin primes and found that there are infinitely many pairs of prime numbers with differences of less than 70 million, thus achieving a breakthrough from scratch on the road to the important problem of twin prime conjecture. ”

Speaking of this, Professor Ren pushed his glasses and wrote Mr. Zhang's proof process on the blackboard.

[Define theta(n)=lnn, if n is prime; Define theta(n)=0 if n is a composite number. Take the function lambda(n)=......, define S1(x)=......, S2(x)=......]

[Verify S2−(log3x)S1> 0……】

【……】

Looking at the ever-increasing formulas on the blackboard, the students who could still understand it before were instantly confused.

For example, the elementary school girl sitting next to Lu Zhou had a face of "Who am I?" "Where am I?" "What am I dictating?" expressions. It's as if you've missed a second, but you feel like you're missing the whole world......

Lu Zhou can keep up with the professor's train of thought.

To put it simply, Mr. Zhang cleverly chose a lambda function and successfully proved that the effect on k> =3.5*10^6, conclusion S2 − (log3x)S1> 0 established.

In this way, listing the first 3.5*10^6 primes as an acceptable set further proves that there are infinitely many pairs of primes with differences of less than 70 million.

"According to the proof method left by Mr. Zhang, as of now, Mr. Zhang's k> =3.5*10^6, which has been narrowed down to k> =50。 That is, the number of 70 million has been narrowed down to 246. The rest of the work needs to be done by the latecomers,"

Speaking of this, Professor Ren smiled and threw the chalk head on the lectern, "Perhaps, the great man who has completed this historic work will appear among all of you here." ”

"I'm looking forward to that day!"

Bang Bang Bang!

Thunderous applause.

The audience applauded.

Whether you understand it or not, it's right to applaud at this time!

Of course, there are still many people who understand, and a thoughtful expression appears on their faces.

For example, land boats.

The twin prime conjecture is just an introduction, and this semi-popular science lecture is not an academic presentation, but the focus is to stimulate students' enthusiasm for mathematics.

Professor Ren talked about the Goldbach conjecture from the twin prime conjecture, and then talked about the recent development of number theory in China from the Goldbach conjecture, as well as some cutting-edge research results.

I have to say that the old professor does have some ink in his stomach.

I can talk about some obscure things that even beginners can listen to with relish.

However, the content of the second half of the lecture was much less nutritious than the content of the first half, so that Lu Zhou didn't listen carefully at all. At this moment, his mind was still on the proof of the twin prime conjecture.

Thinking back to the last time he found in the library, Lu Zhou, who was staring at the calculation on the blackboard, frowned, and felt that he had found something, but he always let it slip through his fingers at the moment when he was about to catch it......

The lecture ended quickly.

The student council took the list and went to the first row and began to count the check-ins.

After Lu Zhou signed in, he couldn't wait to rush to the library, but was stopped by the freshman girl who was sitting next to him just now.

"Senior, senior, wait a minute, that, can you add your buckle?"

Not wanting to waste time, Lu Zhou casually wrote a string of buckle numbers on the scratch paper she handed over, and then didn't give her a chance to continue talking, and quickly walked away in the stunned gaze of the schoolgirl.

However, as soon as he went out, he was stopped by another person.

This person is none other than Professor Ren, who gave the lecture just now.

Judging by the smile on the old gentleman's face, he must have been waiting for him at the door of the lecture hall for a while.

"Hehe, young man, let's meet again."

Lu Zhou: ???

We've seen it?

I seem to have seen it somewhere......

Without waiting for Lu Zhou to react, the old gentleman Ren continued to speak again.

"Boy, are you interested in going to the rocket?"

Lu Zhou, who was still thinking about the question of twin primes, was taken aback by this sudden question.

Nima, is this to make yourself an astronaut?

How can this work!

Lu Zhou smiled awkwardly: "Uh, professor, I don't want to go to heaven yet." ”