AT&T went up suddenly, and it went up again and again, every day.

On Monday, AT&T closed at 22.

Tuesday, 24.5.

Wednesday, 27.

On Thursday, AT&T miraculously broke through the 30 mark and closed at 31.

The New York Stock Exchange is open five hours a day, six days a week. Friday's newspaper reported Thursday's closing price, and Li Kangping felt that AT&T would continue to rise today.

With a happy mood, Li Kangping entered the classroom, where he would be tested by calculus.

The final test paper of calculus was distributed to every student, Li Kangping quickly browsed the test paper, this paper has a total of three questions, and he did not write how many points each question has, it may be that all three questions are all right to get A, do two questions right to get B, do one right question to get C, all wrong is over.

The first question, find a limit, simple.

The second question, making a Green's formula, is equally simple.

No matter how good the traverser is, he can't avoid these things, you have to take the exam, and you have to score the points.

Third, if f(s) is any continuous function, prove that g exists such that ∫K(s,t)g(t)ds=f(s).

This is an over-the-top question, which is Hilbert-Schnitt's theorem, which belongs to the content of integral equations.

Li Kangping skipped calculus class several times, and when he didn't skip class, Li Kangping swore to God that the calculus teacher did not explain the integral equations, and the calculus textbooks did not write the integral equations.

Integral equations are a new branch in the field of mathematics, and Hilbert's fanatical promotion of integral equations around the world has made this thing appear on the final exam papers of American college students before it has time to be printed in mathematics textbooks of American universities.

The calculus teacher made it clear that he didn't want to give an A to a student who skipped class!

Fortunately, my math is okay, otherwise I would have to plant on this integral equation, which means B.

B, on the other hand, is a disgrace.

Li Kangping worked hard to write, and after some convergence and solving eigenvalues, he proved Hilbert-Smith's theorem.

After submitting the calculus test paper, Li Kangping completed the academic tasks of this semester, and there is still more than a week before the Christmas holiday, and it is impossible to go back to China for a vacation, the boat journey is too long, and it will take several months to travel back and forth between China and the United States. Most Chinese students in the United States come to the United States to stay for a few years and do not return home without getting a degree.

Since he met Allen, Li Kangping and Allen have eaten six meals, of which Li Kangping paid for three meals and AA three meals.

At this time, Li Kangping did not have much cash on hand, and it happened that Allen received a bachelor's degree in science from Columbia University, and he should celebrate, so Allen took the initiative to invite Li Kangping to dinner, in a Jewish-owned restaurant in East Harlem.

There were no pork dishes on the menu of this kosher restaurant, so Li Kangping looked at the menu and asked, "Allen, have you received the admission qualifications and scholarships for the graduate school?" ”

Alan said with mixed feelings: "All my classes are A's, and there is no doubt that I can be admitted to the hospital, but the scholarship is ...... Wait, I don't know. ”

It's really sad for a student to worry about tuition.

Filet is the most expensive part of the cow, Li Kangping couldn't bear to order Fili, he ordered a cheap beef rib.

Jews are intelligent and good at business, and there are a large number of Jews active in the academic and business circles of the United States.

As the two ate and talked, Li could sense the Jews' concern about the spread of anti-Semitic sentiment in the United States.

"In fact, many Jews in the United States have become secularized, but in the eyes of some people, we Jews will always be a threat." Alan was so helpless that he bordered on numbness, saying, "Luckily, at least in academia, we have freedom. ”

Li Kangping asked, "Where did your ancestors come from?" ”

Allen said: "Germany. ”

"Germany is the center of physics, and the Germans understand this and emphasize it repeatedly."

"Who's to say it isn't."

"Looks like I'm going to have to start learning German, Alan, together?"

"I speak German."

"Well, of course you can speak German, or you can teach me German, a dollar an hour."

"Although I also want to make this money, I really don't have time. Columbia College has a German program where you can register for a German class in the next semester. ”

"Okay, I'll sign up for German classes next semester."

Li Kangping behaved like an old slave this semester, and in order to get credits as soon as possible, he enrolled in three courses that he was good at. Next semester, you should learn something new.

"Hi Robert!" Alan suddenly waved his hand and greeted a teenager who had just entered the store.

The teenager walked over and he responded, "Hi, Alan. ”

Li Kangping looked at the young man.

The appearance of a teenager, he is not tall, he has a pair of talking eyes, his eyes are very beautiful, full of aura.

This young man is strange, and he is not an ordinary boy at first glance.

Li Kangping said, "Robert, take a chair and sit down." ”

Robert asked suspiciously, "I'm sorry, who are you?" ”

Li Kangping smiled and stretched out his hand: "I'm KP Lee, Allen's classmate and friend." ”

Robert shook hands politely: "Mr. Lee, it's a pleasure to meet you, I'm J. Robert Oppenheimer." ”

Li Kangping smiled and asked: "Your first name was also J, so are you two relatives of the same family?" ”

"I'm kind of a distant relative to Robert." Allen said.

The two-person dinner turned into a three-person interaction, and the young J. Robert Oppenheimer was happy to socialize with his college brother from a prestigious university.

Like Allen, Oppenheimer, 16, is a descendant of German-Jewish immigrants who was born in New York and often goes to his hometown in Germany during the holidays to play and speaks German fluently.

"This restaurant is called Oppenheimer's Restaurant, so this restaurant is owned by your family?" Li Kangping asked Oppenheimer.

Oppenheimer nodded and said, "Yes." ”

Well, Master Robert, a high school student, used his winter vacation to visit the store to see how the business was doing.

Business in the shop was good, and Master Robert was satisfied.

The young Oppenheimer was not simple, he not only spoke German, but also knew Greek and French, and all A's in mathematics, chemistry, physics, history, and English literature.

"Horseback riding? Hike? Glide? Sailing boat? Robert, your interests are too broad. ”

Li Kangping was amazed that Oppenheimer not only had excellent academic performance as a teenager, but also was very good at playing. Some talented teenagers are tired of playing ordinary games, and they are afraid that they will try more exciting projects.

After eating and leaving Oppenheimer's restaurant, Li Kangping bought some Christmas cards.

Professor Compton, Washington University in St. Luth, Merry Christmas.

Mr. Michelson, University of Chicago, Merry Christmas

Professor Woodgate, University, Merry Christmas.

Professor Rosberg, this school, teachers and students, let's send him a greeting card.

After these professors have made arrangements, the next step is to arrange the connections of the New York Chinese Alumni Association.

Mr. Zhou, Brother Debang, Brother Yue Lin, and the rest of the brothers, each of them will send a card.

There was also a Mr. Strauss, Li Kangping did not have much contact with this gentleman, he thought about it, acted according to the rules, and sent a greeting card to Mr. Strauss.

Allen, Jennifer, these two friends are also one person and one card.

Now that the cards are all arranged, let's arrange the Christmas presents.

Christmas gifts are not given by everyone, and friends whose friendship rises to a certain level will receive a Christmas gift from Li Kangping.

Mr. Zhou's taste is high, and he can't give ordinary gifts. Li Kangping spent $21.5 to buy a gentleman's hat that is said to be the most tasteful in New York at a tailor shop, and prepared to give it to Mr. Zhou.

"This tie is good, for Alan."

"This style of tie is really good, give me one for myself."

It is difficult for a person's consumption habits to change in a short period of time, and Li Kangping really can't be extremely frugal.

There was only a little cash left in hand, and AT&T, which had risen to 36, strengthened Li Kangping's courage.