Chapter 411: Song Yao

Monday.

Xu Qingzhou stood at the classroom entrance, looking at the lively scene inside, an expression of surprise appearing on his face.

Last time there were only a sparse twenty or so people, but this time not only were the seats full, but people were even standing in the corridors.

Among the crowd, one could occasionally spot a few middle-aged faces; they looked like professors and scholars from MIT.

Quite popular.

As Xu Qingzhou walked in, the previously noisy classroom suddenly went quiet.

Everyone's gaze fell upon him.

Xu Qingzhou's expression was calm as he walked onto the podium. "Good afternoon, everyone. I'm very happy that so many people are interested in my class."

He did not change the pace or content of his lecture because of the extra people.

"By this morning, I had received 6 solutions to the last assignment. As for the results, there were no problems. I have already written clearly in the emails where certain improvements could be made. Now, it's time to listen to my train of thought."

Xu Qingzhou picked up a marker, wrote down a row of formulas, and said, "First, I will consider starting with the summation on the right side of formula (8) above. Of course, for the sake of better generalization, I will replace ψ(x) with any function f defined on positive real numbers ≥1."

"."

In just over ten minutes, several rows of formulas had already appeared on the whiteboard.

Below the podium, many people nodded slightly, sighing that he was indeed a big shot who had solved three prime number conjectures.

The verification was simple, the logic clear, and there wasn't a single redundant step throughout the process.

Just speaking of the calculation process, it was far superior to theirs.

These were the thoughts of the auditors.

As for the students who came to listen last time, a considerable portion were already struggling, unable to keep up with Xu Qingzhou's rhythm.

However, Sun Simin was not included among them. What surprised Xu Qingzhou was that she was actually the first person to send an email.

As for the steps, there was a lot of redundancy, but the result was fine.

It was like the answer to a question being 'd', but she wrote 'a-b-a-b-e-c-r-d'.

Xu Qingzhou went straight from 'a' to 'b' to 'c' to 'd'.

But all in all, Xu Qingzhou thought highly of this girl. Although she seemed a bit dull, she had talent, and she was willing to put in the hard work.

"The handling of the right side is the trickiest part. We will take the innermost summation and handle it separately."

Xu Qingzhou's voice echoed in the lecture hall.

He lectured a bit more deeply, going through the proof of the Prime Number Theorem once.

The crowd below was focused and attentive.

30 minutes passed, and Xu Qingzhou entered the second part of the content: Gauss's research on the distribution of prime numbers in arithmetic progressions and his own research on the distribution of prime numbers in arithmetic progressions when proving the Twin Prime Conjecture.

After all, to study prime numbers, one cannot avoid the problem of their distribution.

By this part of the content, those who could barely understand before also began to fail to keep up with Xu Qingzhou's train of thought, turning into heartless photography machines.

Xu Qingzhou also noticed this change, but he still did not deliberately slow down.

The current content was indeed hell-level for freshmen, but in his view, it was only because the volume was large and it needed some time to digest.

Some who were like fools last class had also understood the previous part of the content this class, hadn't they?

Moreover, increasing the intensity a bit was just right to filter out those who wanted to slack off for credits.

In the corner, ever since Xu Qingzhou started lecturing on new content, Ma Ersi, who had complained about it being simple last class, gradually entered a state of listening to "heavenly books."

He looked at the friend he had just met beside him. "Jamieen, did you understand?"

"I originally thought Professor Norwich's Mathematical Analysis class was perverted enough, but now I realize Professor Norwich is very kind."

Ma Ersi nodded in agreement.

"That's all for today's content. Thank you, everyone."

Seeing that the time was about up, Xu Qingzhou put down the marker.

Ninety-nine percent of the questions were basic, but some of the questions from this group of young people could indeed make one think of some new things.

For example, a young man named Dino Connally just now asked a question about the deviation statistics law of prime numbers.

Very interesting.

It made Xu Qingzhou consider whether to focus on studying the law of prime number distribution alternating between "short intervals" and "long intervals."

Perhaps the Dao to solving the Riemann Hypothesis lay within it.

Xu Qingzhou couldn't help but think of the joke Hua Er En made last time.

A class passed just like that.

Before the end of class, Xu Qingzhou emphasized one last time: "I think it's necessary to remind the students taking this elective course. If you are interested in prime numbers, you are very welcome, but if it's for credits..."

"I suggest you change to other courses before the course selection ends. Otherwise, I can only say with regret that this semester will be very difficult. And, believe me, the probability of getting credits will be lower than the probability of God throwing dice and hitting you."

Whispers immediately came from below, and many people began to struggle with the decision.

Xu Qingzhou didn't care and waved his hand to signal that class was over.

Just as he finished, a young man walked up with a manuscript. "Mr. Xu, I have a question I'd like to discuss."

Xu Qingzhou took a look; it was about the growth problem of the Euler function.

For a considerable number of people, the Euler function is disgusting because its graph seems to have no pattern, making people's heads ache.

The growth law of number-theoretic functions themselves is very elusive, so many mathematicians first discuss the average growth law of number-theoretic functions.

But that didn't seem to work here.

Xu Qingzhou thought for a moment and said, "Generally speaking, the appearance of asymptotic formulas occurs when swapping the order of summation. Perhaps, here we can expand the Euler formula into some kind of summation, and finally... I think Möbius inversion might be used."

The young man pondered for a long time, then nodded excitedly. "Oh, Xu, this idea of yours is truly brilliant."

"Mr. Xu, I heard you are currently studying the Riemann Hypothesis. I have a few pages of research on the Riemann function here." A middle-aged man approached.

Xu Qingzhou looked at it carefully, then began to verify it on the whiteboard.

It really was a bit like an academic exchange meeting.

Rows of complex calculations soon appeared on the whiteboard.

The result was three words: It won't work.

Class was already over, but there were still quite a few people in the classroom.

Sun Simin and the others wanted to broaden their knowledge. Although they couldn't understand it, there was a high-end feeling of sitting and discussing the Dao.

This was the scene a top university should have.

It wasn't until 40 minutes had passed that the classroom finally quieted down.

Several scholars thanked Xu Qingzhou and left satisfied.

Xu Qingzhou was tidying up his manuscripts when he noticed that Sun Simin was actually still there.

"Senior Xu, I have two difficult problems here that I haven't been able to solve for a long time," Sun Simin said timidly.

"Still planning to continue attending the class?"

Xu Qingzhou took the manuscript and asked with a smile. This girl had said before that she was just here to slack off for credits.

"Yeah, now I suddenly feel that prime numbers seem quite interesting."

Sun Simin said embarrassedly.

"Then you have to be prepared to endure hardship."

"I can endure a lot of hardship."

The problem wasn't difficult; it required deriving the Prime Number Theorem from the Sieve of Eratosthenes.

10 minutes passed.

After Xu Qingzhou finished answering the questions for Sun Simin, he went to Professor Roberts' place, intending to ask two questions.

The first was about complex functions, a power series problem he thought of while looking at Weierstrass's series path.

The second was about real number sequences, which was related to the Landau-Siegel zero point he was currently researching.

On this side, Professor Morton's office.

In front of the desk, Professor Morton was staring at the paper on the screen, her expression serious and meticulous.

Opposite her was a twenty-five-year-old young man, standing honestly.

"Hmm, you can proceed to the next step of the work."

Professor Morton finished checking the analysis report and nodded.

The young man breathed a sigh of relief. Before leaving, he glanced at Song Yao, who was reading with her head down on the side, feeling quite amazed.

"Phew, finally passed." The young man walked out the door, let out a long sigh, and just happened to see Kaier beside him, so he invited: "Hey, Kaier, want to go for a drink?"

"I have an appointment," Kaier said.

"Alright, compared to drinking with you, I'd rather invite that girl next to Professor Morton. But I see she's wearing a ring—does she have a lover?"

"Yes, she has a boyfriend, and they love each other very much."

Kaier stopped, turned her head, and warned: "Don't have any fantasies, you... have no hope at all."

After saying that, she strode downstairs.

Beauty knows no nationality; even she, a foreigner, felt that Song Yao was very beautiful.

This friend of hers was a completely different style in front of her boyfriend.

It was just that she was a bit cold.

This might be love, being gentle only to one person.

If Xu Qingzhou knew she used the word "gentle," he would definitely shed tears.

She was clearly violent only to him!

The young man shrugged, already accustomed to being hit by Kaier, and chased after her: "Boyfriend? I'm actually quite curious, what kind of boyfriend..."

"Very outstanding," Kaier said.

"Oh? Do I know him?" The young man was even more curious.

"You know him."

Kaier said. She remembered Granville Xavier talking about Xu Qingzhou before, and even sighing that this Xia Nation person was too amazing.

"Xu Qingzhou," Kaier didn't keep him in suspense.

"Xu Qingzhou?"

The young man was silent for a long time, then slowly sighed: "That is indeed very outstanding. Want to go for a drink tonight?"

"Not going."

"I'm very sad."

At the same time, inside the office.

Song Yao was reading "Microeconomic Theory: Basic Principles and Extensions," her face cold, her slender eyebrows trembling slightly as she thought about the problem.

The fingers holding the pen were slender, and under the light, the fingertips seemed to be glowing.

Next door, the old lady pushed up her glasses, and the eyebrows that were usually knitted tight relaxed.

"Written very well, one could even describe it as perfect. What is your train of thought for the next part?"

Song Yao stopped writing and briefly described her thoughts on the fourth part of the content: "There are three directions..."

8:00 PM.

When Xu Qingzhou returned, Song Yao was lying on the sofa playing with her phone, probably chatting with some girl back home.

The school beauty Song was wearing a white camisole, revealing two smooth calves.

The two legs were crossed... full of temptation.

"I'm back."

"Hmm."

Xu Qingzhou walked into the living room and immediately smelled a faint fragrance. He immediately understood that the school beauty Song had already taken a shower.

"Finished writing the third part?" Xu Qingzhou asked with a smile while putting things away.

He knew Song Yao was going to talk to Professor Morton about the paper today.

"Hmm, got it done." Song Yao nodded and stretched, the clothes on her chest swaying with the movement.

Xu Qingzhou suspected that this girl was planning to seduce him.

Stay calm, stay calm.

Xu Qingzhou took a deep breath. Usually, he was the impatient one; today it was finally the school beauty Song's turn. The tables had turned.

He spread out the manuscript. He had thought of several distribution problems of twin primes while lecturing in the afternoon, just made simple notes, and planned to perfect them at night.

9:00 PM, after getting the notes done, he also consciously went to take a shower.

10 minutes passed, and Xu Qingzhou went to the sofa to squeeze in with Song Yao.

But Song Yao sat up and took the lead in giving Xu Qingzhou a "sofa-dong."

"Mm~"

A long while later.

The two separated, their faces pressed together.

"Phew~"

Xu Qingzhou stared at Song Yao resentfully: "I've been ravaged by you again."

Song Yao rested one hand on the sofa and hooked Xu Qingzhou's chin with the other. "Do you want to play something exciting?"

"???"

What kind of domineering CEO behavior is this?

Xu Qingzhou was a bit confused and didn't react for a moment.

What's the situation? Was the school beauty Song raised by him?!

Wait, he didn't act rashly, suspecting that Song Yao was fishing, just wanting to find an opportunity to beat him up.

This kind of thing, Song Yao could still do it.

This girl often didn't play by the rules.

But...

Although he suspected Song Yao's motives, her appearance was rare.

Royal sister version of Song Yao.

However, Xu Qingzhou still tentatively asked: "Is it the kind of exciting I'm thinking of?"

"Even more exciting than you think."

Song Yao licked the corner of her mouth, even using a royal sister voice, "Teacher Xu, do you want to?"

"I want to!"

Xu Qingzhou swallowed and nodded. Although he felt it might be a trap, he couldn't bear it.

Even if it was a trap, he would jump in!

Song Yao raised her eyebrows: "Then let's start."

"I'm ready."

Xu Qingzhou nodded solemnly, incomparably expectant.

10 minutes passed.

On the sofa, Xu Qingzhou looked at the ceiling, feeling life was meaningless, sighing that his blade was old.

"Xu Qingzhou, are you not capable?"

Song Yao was very happy and pinched Xu Qingzhou's face.

Xu Qingzhou felt offended, took a deep breath, and moved his arms. "I don't believe it, again!"

"Heh, bring it on."

And so.

The two started the second round of the game.

"Double kill!"

"Triple kill!"

"Quadrakill!"

The sound effect of a quadrakill from Song Yao's phone rang in the living room.

Not long after, the second game ended.

Xu Qingzhou's marksman was once again carried by the school beauty Song's Li Bai.

"Facts prove that I am suitable for eating soft rice." Xu Qingzhou put down his phone and stopped struggling.

"Then I have to work harder."

Song Yao raised her eyebrows again, in a very good mood, looking at the night's battle record, and said: "Strive to let you eat soft rice sooner."

The feeling of being carried by Xu Qingzhou was indeed very good.

After finishing the game, Song Yao chatted happily with Zhang Qiong.

Xu Qingzhou pulled on the school beauty Song's leg, flipping through the manuscript from his discussion with Professor Roberts in the afternoon.

10:30 PM.

Song Yao put down her phone and, seeing that Xu Qingzhou didn't react, rubbed against Xu Qingzhou's thigh with her feet.

"Don't disturb my studying."

Xu Qingzhou said without looking up.

"Pfft~"

Song Yao pfft-ed, wanting to pull her leg back, but it was pinched by someone.

Song Yao pursed her lips: "Play something exciting?"

"Again?" Xu Qingzhou expressed suspicion.

Song Yao spoke with actual actions.

Pfft~

Looking again, Xu Qingzhou had already been pressed onto the sofa by Song Yao.

"."

Xu Qingzhou felt a wave of helplessness.

In order to be lazy, the school beauty Song had pretended to be weak for several days, counting the menstrual period... it had been more than ten days, tonight was destined to be a fierce battle.

(End of chapter) ===== CHAPTER 412 =====