Busy days always pass quickly, and in a flash it is the first of February.

Cheng Nuo was busy instructing the newsboys to sell the popular magazine "People" and spread their footprints all over Beiping City as much as possible.

At this time, Wu Yulin was holding a copy of "New Youth", reading it while walking, but he didn't see the road ahead, and plunged into Cheng Nuo.

"Hey, hey, Lao Wu is now the tenth day of the first month, and he doesn't want to kowtow to the New Year, even if he kowtows, he won't have the New Year's money."

"you, I'm addicted to Mr. Chen's "Theory of Literary Revolution", who would have thought that I would give you a big gift?" Wu Yulin raised the magazine in his hand: "People's liberal arts are one achievement after another, why are we making slow progress." ”

Cheng Nuo quietly tucked the newspaper behind him on the table, afraid of being found deliberately prevaricating: "Scientific things, how can you help the seedlings grow, you can't rush it." Besides, didn't I let you and Shi Jin study the tricycle, why did you come here again? ”

"Today isn't the day of the inaugural issue, I came here specifically to care about you, it's enough for the tricycle to have that nerd research." glanced at it, and just saw Cheng Nuo's small movements, and was a little curious: "Hey, what kind of treasure is hidden and you don't want me to see it, is it a fried triangle, and eating alone is not authentic." ”

As he spoke, Wu Yulin put the magazine under his arm and stepped forward to snatch it.

Cheng Nuo had no choice but to take out the thing hidden behind him, that is, a newspaper.

"Hey, isn't it just a newspaper, what's the big deal, can you hide it?"

Wu Yulin glanced at him suspiciously, took the newspaper and browsed it, the smile on his face became less and less, and finally his face was full of frost.

It turned out that Germany was in a tight war and brazenly launched unlimited submarine warfare, not only blockading our waters, but also threatening to sink all ships that passed.

Such warnings did not remain on paper, and later statistics later calculated that in the three weeks of this month alone, 134 ships of non-belligerent countries were sunk by German submarines, causing heavy losses.

"A group of rice buckets, all stabbed into the newspaper, don't the officials take action?" Wu Yulin clenched his fists, and his forehead burst into blue tendons: "Go protest, go break off diplomatic relations, go beat him!" ”

Cheng Nuo shook his head: "At present, it seems that they have not taken the next step and are still waiting and seeing." ”

"Also, the British can't kill their submarines, what can we fight."

"Think about it from another angle, is there more Japanese ships in that area, they have more headaches."

"Drive the wolf and gobble up the tiger, and you will have fun in the bitterness."

Cheng Nuo walked over and patted him on the shoulder: "Our generation should be self-reliant, that's why I invited you, if one batch doesn't work, cultivate the next batch, and you can always see the day of hope." But for now, we're counting on your Applied and Engineering Sciences department to make money to support other departments. ”

"No, isn't our Academy of Sciences just recruited people and hasn't been established yet, when did a Department of Applied and Engineering Sciences come?"

"Just now, hurry up, do a good job, the position of the head of the department is reserved for you."

After drawing the pie, Cheng Nuo can finally return to his old profession and compile mathematics textbooks.

First of all, the lecture notes of the domain theory of this major, and the standardized course is definitely indispensable.

Some professors of the liberal arts department of Peking University like to put aside lecture notes, quote scriptures, and suppress frustrations, so that everyone at the bottom listens to them with relish, and the final exam is all based on the students' notes, and whether they remember it seriously or not, and the textbooks are none.

Of course, this method cannot be tried by ordinary people, so after listening to the lectures of several teachers, Cheng Nuo decided to compile a textbook of class domain theory according to the later generations, which is convenient for students to review and is also conducive to the dissemination of knowledge.

Secondly, a brief history of algebraic number theory should be written to cultivate students' interest.

Mathematics is not an easy course in the first place, and there is no interest in guiding it, so it can only be described as boring.

Fortunately, algebraic number theory has not been developed in this world for many years, and soon the catalog was compiled, and only the content was filled.

In the order from ancient times to the present, they are ancient number theory, medieval number theory, Gauss's "Studies in Number Theory", and Didkin's "Algebraic Integer Theory...... To his recent class domain theory, it is clear at a glance.

Finally, it is Cheng Nuo's long-term project, which is to compile a "Mathematical Dictionary", and he attaches the greatest importance to this work.

It is divided into elementary mathematics to advanced mathematics, classical mathematics to modern mathematics, theoretical mathematics to applied mathematics, and each mathematical term is introduced in easy-to-understand language as much as possible.

Targeting users are no longer students of Peking University, but mathematics teachers in various primary and secondary schools, hoping that the "Mathematical Dictionary" can become their right-hand man.

After all, no matter how hard Cheng Nuo tries, the students he teaches are always limited, but thousands of teachers are different, facing a larger number of students, if there is the help of the "Mathematical Dictionary", the teaching results will be better.

In addition, it can also be placed on students' desks, which is also more convenient for them to solve their doubts.

However, this is a big guy after all, and the workload is not something that can be completed by one person, so after Cheng Nuo arranged the outline, he distributed the easy part to the mathematical talents of the Academy of Sciences and the Mathematics Department of Peking University.

Everyone gathered firewood and the flame was high, and it is expected that the first draft will be completed by the middle of the year.

After a single means, Cheng Nuo faintly became a leading figure in the domestic mathematics community.

As the days went on slowly, the American "Mathematical Yearbook" sent several telegrams in a row, the content of which was basically the same, that is, inviting Cheng Nuo to give a lecture in the past.

In fact, it is no wonder that mathematicians in North America have always wanted to hold the World Congress of Mathematicians in their own countries, but Europeans do not take them seriously, and their applications have been rejected many times.

In order to bring the World Congress of Mathematicians to the world, Fields, the founder of the Fields Medal in Mathematics, traveled for decades to move the conference to Toronto, that is, the 7th World Congress of Mathematicians, which was also the first time that it was held outside of Europe.

Therefore, even if Cheng Nuo is a yellow person, in order to enhance the influence of the North American mathematical community, they have to pinch their noses and insist on inviting him over.

Besides, Cheng Nuo was born in Harvard, and he was more happy that his school had talents, so some small problems were easily solved for him.

Replying to peer questions is a necessary process, but Peking University is about to usher in a new semester, so Cheng Nuo doesn't want to leave the United States now, so he can only answer them in the form of letters.

As more and more homogeneous problems came and went, Cheng Nuo simply sorted out a set of difficult problems, and published a paper in the Annals of Mathematics to further improve the class domain theory.

On the day of school, Cheng Nuo, dressed in a robe, tidied up his collar at the door, pushed the door and entered the classroom.

But when I opened the door, I was dumbfounded, seven or eight rows of tables were all full, and there were even a few standing in the empty space in the back row.

"No, I remember that there are only twelve students in the whole grade of mathematics at Peking University, when will Cai Gong recruit new people?"

If you look closely, how can there be female students, isn't it co-educational?

When they saw the teacher come in, the students immediately fell silent and stood up to salute.

"Hello Professor Tom~"

Cheng Nuo was helpless, and after returning the salute, he carefully wrote a line on the blackboard.

"Welcome to the math paradise."

In particular, the word paradise is bold and enlarged.