Chapter 358

Twenty minutes of essay presentation time.

Cheng Nuo did not hurry to tell the core content of his graduation thesis to the four teachers of the defense team.

The four of them also nodded frequently in listening.

No matter from which aspect, Cheng Nuo's performance in this link is enough to be described as impeccable.

“...... That's all for my statement about the paper. ”

Stuck in time, Cheng Nuo finished in the last ten seconds.

The four teachers of the defense group in the audience also sat up straight in an instant, with serious faces, preparing for the last part of the defense: the defense teacher asked questions.

This is the most important part of the three links of the defense, and it is also called the "ghost gate" by countless graduates.

Extremely difficult questions keep throwing at you like a cannon, and you have to muster up the energy to face it with a smile.

Especially the kind of questions that sound confused, it makes people want to answer, and they don't know how to speak.

There are two types of questions in the graduation defense.

One is that the tutor writes down the questions on a slip of paper, and the candidate has about five to ten minutes to prepare for each question.

After you have prepared your questions, you will answer the questions.

On the other hand, it is more of a test of students' academic level.

That is, the teacher of the defense team asks questions on the spot, and the students answer on the spot, without any preparation time, even a minute.

This form is undoubtedly extremely cruel to the students participating in the defense, but it is the most effective test of their four-year undergraduate studies.

However, considering the graduation rate, half of the defense questions of Tsinghua University School of Mathematics are a mixture of two question forms.

Two questions are given time for students to prepare their words.

The other two questions are a complete test of students' performance.

A few days ago, when the first few students who reported for today to participate in the defense, they all arranged it like this.

However, for Cheng Nuo, this demonic genius, it is obvious that he must be treated differently.

If Cheng Nuo is left with time to prepare, he will be too sorry for Cheng Nuo's reputation as a genius.

Therefore, proposed by Dean Wei, the four of them unanimously decided that all the questions in Cheng Nuo's defense and questioning session would be answered directly on the spot.

"Cheng Nuo, are you ready?" Dean Wei asked with a faint smile on the corner of his mouth as he looked at Cheng Nuo on the defense seat.

Cheng Nuo took a deep breath, "Ready!"

What should come is always coming.

Besides, Professor Youfang and Dean Wei are here, and Cheng Nuo guesses that the difficulty level of the question will probably be very high!

"Then let me ask the first question!" Cheng Nuo didn't expect that the first person to attack was Professor Fang.

Professor Fang sat in the teacher's seat of the defense team and said with a smile, "Cheng Nuo, you have no opinion, right?"

"No, no. Cheng Nuo smiled bitterly and waved his hand.

Professor Fang nodded, and while flipping through Cheng Nuo's paper in his hand, he asked, "The inference 10 drawn on page 15 of your paper, the specific reasoning steps are too brief, can you prove it again with a specific formula on the spot?"

The specific proof method of inference 10?

Sure enough, the teacher is more reliable, and the first question is not too difficult for himself.

Cheng Nuo smiled faintly and bowed his head slightly, "No problem." ”

After speaking, Cheng Nuo picked up a piece of chalk on the podium and began to write the blank side of the blackboard.

This is not a lecture, and there is no need to write and lecture at the same time.

Cheng Nuo only needs to write out the detailed derivation steps of Inference 10.

This is not a problem for Cheng Nuo at all.

Although Corollary 10 is a corollary that has been "discarded" in the proof of Bertrand's hypothesis, the specific proof steps are still memorized by Cheng Nuo.

[Because n ≥ 3 and 2n/3 2n, there is only i = 1 term in the summing formula, i.e., s = floor(2n/p)- 2floor(n/p). Since 2n/3 < p ≤ n also indicates that 1 ≤ n/p < 3/2, so s = floor(2n/p)- 2floor(n/p)......]

【...... θ(n)≡Σp≤n log(p)< n log4，...... In summary, we can get Πp≤N p =(Πp≤m+1 p)(Πm+1

Get!

Cheng Nuo turned around and wanted to handsomely throw the chalk head back into the chalk box, but when he thought that this was the scene of the graduation defense, he took back his raised hand and stood aside awkwardly.

In the audience, the four defense teachers stared at the half of the blackboard that Cheng Nuo had written for almost a minute.

With their mathematical ability, it is not difficult to quickly read and understand the formulas written by Cheng Nuo, and besides, they themselves have a certain degree of understanding of the content of Cheng Nuo's paper.

Professor Fang smiled and said, "Yes, I'm very satisfied. ”

After asking a question, Professor Fang didn't hold on to Cheng Nuo anymore, and after nodding with satisfaction, he stopped talking.

The next question is asked by two other professors in the defense team.

The questions raised were all answered easily by Cheng Nuo.

It's not that their question isn't difficult enough, it's that Cheng Nuo is too perverted.

In fact, the two questions they asked, even if they were asked to answer by a few top students who graduated from the Academy of Mathematics, it would be tricky.

But they were facing Cheng Nuo, a student who was far more than their cognitive genius.

For that kind of difficult question, Cheng Nuo can go through it all the way by chopping melons and vegetables.

But Cheng Nuo, who easily handled the first three questions, did not show too happy expression on his face, because he knew that the biggest difficulty in his graduation defense had not yet appeared.

That's Dean Wei, since he is willing to go down to participate in the defense in person, it is definitely not just to see how Cheng Nuo pretends to be forced at the defense scene.

The first three questions are just appetizers, and the last question is the final boss!

When it was Dean Wei's turn to ask a question, he looked at Cheng Nuo not far away, and smiled as if a villain had come out.

Cheng Nuo's forehead instantly broke out in several cold sweats.

Dean Wei took out a document from the briefcase on the side without hurry, put it on the table, pointed at it, and asked with a smile, "Classmate Cheng Nuo, do you know what this is?"

Cheng Nuo shook his head, "Students don't know. ”

Dean Wei beckoned to Cheng Nuo, and when Cheng Nuo approached, he handed the folder to Cheng Nuo, "Take it and take a look." ”

Cheng Nuo took it with a suspicious look and opened it.

When he saw the title of the document, his pupils shrank suddenly.

Then, he hurriedly turned the first page, and his face changed again.

Dean Wei smiled in a non-hurried tone and said, "After I got your paper that day, I also became a little interested in the proof method of Bertrand's hypothesis. ”

"Ah, the paper you're holding in your hand is another Bertrand hypothesis proof that I wrote in three days. ”

Hiss——!

Not only Cheng Nuo, but the other three professors also gasped.

"Don't be so surprised, I haven't finished yet!" Dean Wei scolded with a smile, "This paper, uh, how to put it, is a failure, because I found out that there was a logical error in one part of the paper. ”

Dean Wei's face was straight, "And Cheng Nuo, the test I gave you is to find the logical errors in this paper within half an hour." ”

"Of course, if you can also correct this logical error and make the whole paper logically smooth, I will give you full marks directly for this graduation defense!"