"The extreme value principle plays a very important role in the study of partial differential equations, combined with the above reasons, I have summarized several extreme value principles of partial differential equations, and also given some applications of several extreme value principles" In the conference room of the mathematics department, a senior student is slightly nervous expounding the outline of his thesis.

As the No. 1 department in the country, the Department of Mathematics of Beijing Normal University is not like those schools that can graduate as long as you pay the money, and the graduation thesis card is still relatively strict; for those papers that have problems such as low quality, problems with logical order, and insufficient authority of the cited materials, they usually will not pass easily, so except for the student who is defending, everyone else is also nervously looking at their papers; only Lu Qiujian still looks relaxed.

This semester, Professor Nan also returned to Beijing Normal University, and now he is sitting on the stage listening carefully to the student's report, and after he finished the report, he moved the microphone to his mouth and asked, "Tell me why you used that formula in the fifth subsection of the energy model estimation section, is this formula the best choice for this problem?"

"Well, that's what I thought" The students below obviously heard his voice trembling a little, and even their own feelings became nervous; Professor Nan in front of him had given the students the questions of the final exam for the seven major mathematical problems! Compared with the graduation thesis, the requirements will only be higher!

Why didn't he come back half a semester late, we didn't take his classes and still had to be assessed by him, what a big loss!

"It's not appropriate for you to put this formula here, you didn't take into account the problem that still needs to be solved, and you didn't make up for this loophole in the following articles!" As soon as he finished answering, Professor Nan shook his head and unceremoniously pointed out the error, "So, there are major flaws in your paper!

"Ahem, Professor Nan!" Professor Zhang couldn't help but interrupt him, although there were certain problems with this paper. But it's not irreparable, don't just shoot this kid to death!" "I think it's better for him to go back and revise it, and then defend it again!"

"Well, so be it!" Professor Nan hesitated for a moment and agreed with Professor Zhang's opinion.

"Thank you Professor Zhang, thank you Professor Nan, thank you Professor Ren" The child was about to cry when he was wronged, and he had to bow and thank him one by one.

There is such an example, the next student who defends is more nervous, but the more nervous he is, the more likely he is to make mistakes, and some of them have no problems with the thesis. But when Professor Nan asked, his brain was a little confused, and the words that came out of his mouth did not reach the meaning, and he soon suffered a fate similar to that of the classmate just now.

Xu Ye and Li Yincheng, Lu Qiujian's roommates, were better, they had asked Lu Qiujian to help them read their papers, and the slightly obvious problems were dealt with, so they passed this hurdle and successfully passed the defense.

"Classmate Kong Yuan, please come forward to defend, classmate Lu Qiujian, please get ready!" The time for the defense passed quickly, and it didn't take long for Lun to arrive at Luqiujian. He took the thesis out of his bag and prepared for defense.

"Well, you can answer a few questions okay, and it can be seen that your preparation is relatively adequate!" Professor Nan said after hearing Kong Yuan's answer. "It's just that there are a few details that are not very perfect, and I will let you go through this defense, but if you want to publish it, I am afraid it will need to be more perfect. ”

"Yes, thank you Professor Nan, thank you Professor Zhang" Kong Yuan let out a big sigh. Holding back a smile, he bowed and thanked him one by one.

Then it was Lu Qiujian's turn, and almost everyone in the conference room turned their eyes to it, and people from other classes in the next conference room also sneaked in, wanting to see how this legend of Beijing Normal University was doing when defending his thesis.

"Huh. Xiao Lu, you have been in the high-energy institute for several months! You haven't seen him much since Professor Nan returned to China, this is a bit undeserved!" Before Lu Qiujian began to elaborate on his papers, Professor Zhang said with a smile, if it weren't for the increase in the papers issued by Lu Qiujian during this time, he would have gone to the high-energy institute to find him out!

"Yes, this is mine, no! I will definitely make amends to Professor Nan when I turn around!" After Professor Nan returned to China, he only met once at the welcome party on the first day, and since then he has been staying in the high-energy institute, which is a bit unkind.

"It's okay, it's okay, you can see me at any time, this kind of learning opportunity is not available all the time, and besides, your recent article has given me a lot of inspiration!" Professor Nan changed his stern approach and generously disagreed.

"Are you still used to staying in Gao Neng?" if you want me to say that their canteen is really not like a word, I went there last time, and the braised pork was roasted, and I really wasted those good pork belly with a mouthful of oil!" Professor Zhang grinned as he spoke, as if there was really such a piece of braised pork in his mouth.

"If you want to say that this is compared with universities and research institutes across the country, it is still the best braised pork in the small cafeteria of Tancheng University! That is really a sweet and fluffy, fat but not greasy" Professor Ren, who had not asked much questions just now, was also interested and joined in their conversation.

Lu Qiujian and the students in the audience were messy in the wind, teacher, this is the defense of the Department of Mathematics of Beijing Normal University, not the graduation project assessment of Neweast Culinary School!

"Of course, I don't care what kind of place Tancheng is! The braised pork came from them!" Another professor spoke, "If I want to look at colleges and universities across the country several times, there is no one whose meat is better than theirs!"

"If you want to just say it's braised pork, I'm fine! But I don't agree with expanding the scope to meat!" Someone immediately stood up and objected, "Dongpo meat from the Academic Exchange Center of Wuyue University! Guyu meat from the expert canteen of Yuedong University! There is also roasted white meat from the Institute of Religious Studies of Shuzhong University! That is not lost to him! I am only talking about pork, and I haven't mentioned the yak meat from Tubo University, the finger mutton from Xiyu University, and Baodao University."

Seeing that the topic was a little far away, Professor Ren hurriedly patted the table, "Everyone, I want to eat meat for a while, I'll treat you, let's defend it!"

At this time, everyone woke up from the lively discussion, Professor Zhao smiled embarrassedly, and then looked at Professor Nan, "Professor Nan, you see that the time for this defense is almost over, Xiao Lu will pass over directly, right?"

"Well, let's get over it!" the students in the audience were messy again! )

PS: Well, you can go abroad in the next chapter. Thanks to the 588 reward of the Second Emperor, thanks to Eckel Fallon, Pegasus Chunqiu, the vest of the winged demon, book friend 110614200135495, Feilian messenger, big cat cat's eye, Xuanyuan Changlei, the sun and the moon are the same light, jony100 with the wind, four cola bottles, inflation, book friend I am Brother Qiang, ~. Meow a tip.

Thank you for the monthly passes of sojsoj, eddychen5015, niuyutu, Dream Infinity 99, Book Friend 110614200135495 and others, woo woo, it's so slow to rise after double the time!