On the other side of Kyoto Yanjing, the family is eating happily, and the family of three is happy.

The man suddenly received a phone call, it was the old father. The man listened for a moment and then nodded his head, as if he had agreed to something.

"Who's calling, what's the matter?" Seeing the man hang up the phone, the woman frowned and asked. When eating, the most annoying person called.

The man said, "Good thing, my dad called me and told me something." This weekend, let Duoduo go to live with him for two days, and by the way, let someone make up for her math scores, which is still free. ”

The woman said, "It's no problem to live with me in the past." But it's a little inappropriate to make up classes, right?,Who is Dad looking for? This course is not something that anyone can make up, in case you miss the teaching, you will make a mistake when you go back to the high school entrance examination. ”

The man gave the woman a reassuring look, "Then you can put your heart in your stomach." My younger brother is the younger brother who came here last time, and he studied mathematics at Yenching University, so it must be no problem to tutor Duoduo's junior high school homework. ”

"Not necessarily." The woman quite disagrees with her husband's opinion, "If you learn well and take the exam well, it doesn't necessarily teach well." ”

"Okay, okay, okay." A man is not in a strong position at home, so he doesn't quarrel with his wife at this time, "You have a rest this week anyway, accompany Duoduo to go to my parents' place to see how my brother's counseling is." ”

"If it doesn't work, just say it tactfully to your parents. If you can do it, let Duoduo learn from it. This outside tutorial class is not cheap! ”

"You're not going! I haven't seen your brother in a long time. ”

"I'm on the night shift, so I don't have time." The man said, "Just now my dad said that my brother's personality has changed a lot, and he is much more cheerful. If I didn't have time, I would like to check it out. ”

···

After having lunch at his uncle's house, Ji Zhen said goodbye and made an appointment to come next weekend to tutor his little niece by the way.

For the next two days, Ji Zhen accompanied Xu Linfei during the day. didn't do anything earth-shattering, just pressed the road, watched movies, and ate.

But such a warm moment made the two very intoxicated.

On the third day, Ji Zhen sent Xu Linfei north to Changchun's plane.

"Chasing the Murderer in the White Night" has started filming!

It's winter now, and I just happened to shoot the scene in Changchun first.

Before the tutoring began, Xu Linfei also left. There were not many courses in college, and they were not too difficult, so Ji Zhen put his focus on the proof of Poincaré's conjecture.

With the money borrowed from Xu Linfei, he rented a house, and then bought four large blackboards.

After the preparations were done, Ji Zhen began to recall the memories in his mind and began to work.

While reminiscing, write the highlights on the board.

"It's hard, it's too hard." About two hours later, Ji Zhen put away his memories and looked at the four blackboards in the room, his face couldn't help but be a lot more solemn.

Ji Zhen in his previous life was not a major after all, and he had never really understood the top-level mathematics major.

So I thought it would be easy. But now it seems that it was a big mistake.

If it's just a full verification from memory, it's really not that difficult. But that didn't work, they didn't eat the mathematical knowledge thoroughly, and other math majors revealed their stuff when they asked.

And if you want to understand this proof process thoroughly, it is not easy for Ji Zhen at this time.

"Although I studied mathematics at Yenching University, I only had an undergraduate degree after all, and the depth and breadth of my mathematical knowledge were still very shallow. There is still a long way to go to fully understand the process of verifying the Poincaré conjecture, one of the seven major problems in mathematics! ”

Mathematics is only two words, but it contains a lot of things. On the contrary, the scope of coverage is extremely wide.

The large branches alone include more than 20 branches, including mathematical logic and mathematical foundations, number theory, algebra, algebraic geometry, geometry, topology, mathematical analysis, non-standard analysis, function theory, ordinary differential equations, partial differential equations, dynamical systems, integral equations, functional analysis, computational mathematics, probability theory, mathematical statistics, applied statistical mathematics, operations research, combinatorics mathematics, fuzzy mathematics, quantum mathematics, etc.

Not to mention that there are many smaller branches of mathematics within these large branches.

In the verification of Poincaré's conjecture, many kinds of mathematical ideas and methods intersect with each other, and there is no certain mathematical foundation, which is by no means something that can be understood in a short time.

"It seems that it will be a while before the next boundary crossing is crossed. First of all, use the technique of derivation to thoroughly understand the proof process of this Poincaré conjecture and the mathematical knowledge revealed in it. ”

Breaking boundaries is a matter of moments, and the art of derivation certainly has a time limit. The current season is really only one hour.

And within that hour, Ji Zhen's thoughts will run very fast, all kinds of inspirations will come one after another, thinking about the questions clearly and concisely, and it is no longer a problem to remember and draw inferences.

It's as clear, fast and easy as a math professor doing elementary school addition and subtraction.

"A deduction technique is only an hour, and if you want to fully absorb and digest the mathematical knowledge contained in it, you need to perform about three deduction techniques."

"Well, in that case, then my top priority is to increase my mathematical knowledge base."

The art of derivation is not made out of nothing, but from simple to complex, from basic to professional, and from present to the future.

The same is true of mathematics, only when there is a wealth of mathematical knowledge in the mind, can it be smoothly sorted out and digested.

Derivation is a process, not a result. It is the process of transforming what is not understood in the mind into understanding.

In the art of derivation, it is impossible to derive partial differential equations from addition and subtraction alone. However, if you have all the math knowledge of junior high school, high school, and college in your head. Although this knowledge may not be understood at all, it can be deduced.

Just like building a house, dirt can't become a house on its own. But when you burn the clay into bricks, then architects design it and builders build it, and you can turn it into a house.

And derivation is the process of turning dirt into a house. Now Ji Zhen wants to increase the soil in his mind, otherwise, this 'house' will not be completed.

At this time, Ji Zhen doesn't need to understand these 'soil', when his 'house' is in hand, he understands the whole 'house', and he also understands all aspects of the 'house'.

This is the effect of the art of derivation, weird and powerful!

After readjusting his plan, Ji Zhen began to act. Like his roommates, he made a home in the library.

The library not only has paper books, but also an electronic reading room, where you can consult foreign mathematics journals and better enrich your mathematical knowledge.

Of course, don't forget to tutor your little niece.