"Oh? It's Jun! Professor Hu opened them, and when he saw the door, he was stunned for a moment, and then warmly greeted Junxin into the compartment.

"Hello Hua, good Professor Hu!" Junxin put the plate on the table and said hello.

"Xiaojun, how are you, I haven't seen you for a long time, sit down!" Hua Lao looked very happy when he saw Junxin, and beckoned him to sit down.

Jun Xin thanked him, then sat down and asked, "When did you come back?" Why haven't I heard from you all this time? ”

"Hehe, I've been back before!" Hua Lao replied with a smile, "I was in Shanghai before, at the invitation of Mr. Su Buqing, I gave a lecture at Fudan University, and then went to my hometown. As a result, he was arrested by the University of Science and Technology of China, and he didn't come back until the day before yesterday. ”

Junxin suddenly, no wonder there have been rumors that Hua Lao is going to return to China, but although there are rumors, he has never seen it, Junxin thought it was a miscommunication, but now it seems that those news are really not groundless.

"About the paper, I'm tired of you getting old!" Junxin said very gratefully.

Hua Lao smiled and waved his hand and said, "It's nothing, I was going to go to the United States for an academic visit, and your business was just incidental." ”

Having said that, if it weren't for Junxin, Hua Lao would not have gone to the United States in such a hurry. So Junxin is still very grateful to Hua Lao, but Hua Lao said so, and Junxin did not show it verbally, but remembered it in his heart.

"You got old and went to the United States, did you gain anything?" Junxin asked curiously.

Hua Lao put down the chopsticks in his hand and said with reminiscence: "Returning to the Institute for Advanced Study in Princeton made me feel a lot of emotion. Needless to say, the reception of the school, with several familiar professors chatting and discussing new development issues, made me feel the passion of the work in the forties. It's like going back to the era of communicating and working with Professor Einstein and Mr. Yang Zhenning. It's a really memorable feeling. ”

Jun Xin naturally knows about Hua Lao's life well, knowing that he studied mathematics under the guidance of Hardy in England, and gave up the title of doctorate in order to learn more. Later, he went to the United States and stayed at Princeton for four years, forming an indissoluble bond with Princeton. In those four years, the Princeton masters were like a cloud, and the rest of the people were left alone, and Mr. Einstein's work at the Institute for Advanced Study in Princeton alone was enough to explain everything.

"Have you seen Elder Chen? How is he now? I even communicated with him some time ago! Junxin asked with concern.

"When I met Brother Chen, he was better than my body!" Hua Lao said with a smile, "He is a little purer than me in academics, which makes me ashamed." When chatting with him in the United States, the two of us also talked about you by the way, and Brother Chen spoke highly of you. ”

"That's the wrong love of the seniors." Junxin waved his hand and said.

"You don't have to be modest!" Hua Lao approvingly, "But anyway, you are going to the United States, it is indeed a better place to go to Princeton to study mathematics, and it would be good for you to go and see Brother Chen when you have time, he is also very interested in meeting and chatting with you!" ”

"Mr. Chen has reached the pinnacle in the field of differential geometry, and it is my honor to have his guidance!" Junxin said expectantly.

"What are your plans for when you return home?" Professor Hu on the side asked.

"Hehe, I guess I won't go back to school to teach!" Hua Lao said a little sadly, "In the future, I estimate that I will have to run around the country to promote my optimization method and overall planning method, I hope to get everyone's attention!" ”

"The truth of science has always been that the few lead the majority, and the majority always represents error and backwardness!" Professor Hu said with emotion, from Hua Lao's words, he actually heard a trace of martyrdom, which made him a little sad.

"But at least the general trend is always forward!" Junxin added. He understood Hua Lao's determination. After all, Hua Lao is old, and his heart is not good. When Mr. Hua went to Japan to give a lecture in 1985, he jokingly told his disciple Mr. Chen Jingrun that maybe he would be hospitalized with Mr. Chen for recuperation after returning to China. But as a result, Hua Lao never came back as soon as he went...

"Don't talk about it." After all, Hua Lao went through ups and downs, and quickly adjusted his mentality, and asked, "Xiaojun, you have already decided that you are going to Princeton University as an exchange student, right?" ”

"Yes! I'm going to leave at the end of July, fly first to England and then to Canada, where I'll stay for a while to attend the International Union of Crystallography, and then I'll fly directly from Canada to New York, and from there it's a quick trip to Princeton. When he received the notice of the exchange student, Junxin had already planned his route, and now that Hua Lao asked, Junxin was naturally able to say it immediately.

"When Brother Chen received your letter, he mentioned that you explained the problem of quasicrystals to him in the letter, and Brother Chen also specially found your article published in "Advances in Mathematics", I deduced it with him in mathematics, and came to a completely correct conclusion, after reading your paper published in "Nature", Brother Chen was amazed by your wonderful idea, and even wrote a letter to Professor Penrose of Trinity College, Cambridge University, England, when I returned to China, Professor Penrose's reply had not yet arrived. So if you want to know the content of the letter, you have to go to Brother Chen yourself. ”

"There's no rush on this matter, just wait until we get to the United States." Junxin is not in a hurry about this.

"What have you been working on lately?" Hua Lao asked with obvious interest.

Jun Xin thought for a moment and replied: "I got some inspiration from the grand unification theory in science fiction novels some time ago, and I am currently studying a more interesting theory in the grand unification theory. In general, my current research focus is on mathematical physics, and the first paper has been sent out and the second article is being prepared. ”

"There are a lot of math problems and physics problems that can be figured out, if you are interested in this, go and study it, and if there is anything you need my help with, just say it." Hua Lao said gently. As a person who has worked with Einstein and Oppenheimer, he naturally has a far more understanding of the connection between mathematics and physics, so he does not think that Junxin changed his major.

"There's really one thing I want to ask you to be old!" Junxin is also not polite, after getting acquainted with Hua Lao, Junxin admires Hua Lao's moral integrity very much, so he doesn't think this is Hua Lao's polite words.

"What's the matter?"

"Well, that's right, when I was teaching at the University of Science and Technology of China, I was interested in the twin prime conjecture problem, I used Hardy's method to analyze its sufficient conditions, but it was just an estimation method, so I wanted to study it further, I wanted to use the sieve method to deal with it, I thought of an idea, but because of the lack of understanding of the sieve method, I wanted to meet Mr. Chen Jingrun, and wanted to understand his proof ideas in detail."

"Can't I take you there?" Professor Hu asked dissatisfiedly.

"Of course not!" Junxin shook his head and said, "I've been busy with other things lately, and I've just forgotten about it." Now that I think about it, I don't bother the two masters, and by the way, I ask Hua Lao to do me a favor! ”

Although Hua Lao is no longer engaged in front-line research, he is still very interested in the field he is familiar with, and immediately agreed, and the time was set for three days later.