Things will be very difficult at the beginning.

Every weekend, Lin Chaoxi would go to Hongjing Library. This was a fixed schedule for her and Pei Zhi. Sometimes Old Lin would be there, sometimes not.

When Old Lin was not around, Lin Chaoxi would put down his advanced mathematics studies and start messing around among the bookshelves.

The rows of bookshelves where she stood the most were those related to computers and mathematics. She would occasionally browse the shelves related to transportation, and feel dizzy looking at the large number of traffic regulations, highway construction foundations, and bridge structures.

She didn't actually know what she was looking for.

When you have an idea, you knock on the door and go in. The feeling inside is completely different from being outside. You will find that you have actually entered a pitch-dark space.

Because of the darkness, she lost the sense of comparison between big and small, and felt that she was becoming increasingly insignificant, as tiny as a speck of dust; and this space was so vast and boundless, like the universe.

If it was her before, she would have given up on the idea after thinking about it, and would not really take action. But at least she has a chance to do it again. If she still doesn't dare to try because of the fear of failure, she would be like a fool.

She didn't know much, but she knew that although the existing knowledge in this world was vast, most of it was hidden in libraries and compiled into books by knowledgeable people.

When you cast your net, you should always be able to catch something.

Therefore, she would flip through every book on the bookshelf, look at the table of contents and preface, and she would mark down the bibliography and information that she thought was useful.

This was a stupid idea. Generally speaking, even the Hongjing Library had a very large collection of books, and when there was too much information, it would be difficult to sort it out. So for a while, she felt like she was caught in a spider web, and she always felt that everything she saw was useful, but she had no ability to classify and sort it out.

She thinks each one of them is useful, but she has no ability to tell whether they are really useful.

When she was most troubled, she felt that the "………………" following the book catalogs were like sticky spider webs.

She must have been very anxious during that time, so much so that Lao Lin couldn't help asking her, "What's wrong with you recently? Is calculus so difficult?"

Lin Chaoxi pretended that nothing had happened: "It's okay. I didn't find it that difficult after I learned it."

"Why is it that there are so many seniors who confessed to Pei Zhi?"

Lin Zhaoxi: “…”

Wearing an apron, Lao Lin patted her shoulder with a spatula and said earnestly, "Dad can't help you with this."

The more relaxed and humorous Lao Lin appeared, and the more indifferent he seemed to everything, the more anxious Lin Chaoxi felt.

"I need some guidance," she said.

"What kind of guidance?"

Lin Chaoxi really wanted to say, "I want to know how I can save you," but if it were Old Lin, he might have said, "No need to save you," and the reason for not saving you might be something particularly meaningless like "life and death are both life experiences."

So she lowered her head and thought about it, and decided to change the question.

“Have you ever had a moment in your life when you felt completely lost?”

"I don't understand your question."

"It's like when you were in elementary school, you were determined to solve a very, very difficult math problem, similar to the Millennium Puzzle, and then you realized you had no direction and were just daydreaming."

"The Millennium Problem has actually accumulated a lot of research from previous generations, so it's not completely directionless. At most, it just takes some time to explore."

"Have you ever not been faced with a huge problem, and felt completely at a loss as to what to do?"

"Yes, I have."

"When?"

"When I found out I had a daughter."

Lao Lin was very calm.

The weather was warm, and they sat under the flower stand. The grass in the yard was lush, but Lin Chaoxi's nose was sore: "Don't be so sentimental all of a sudden!"

"real."

After Lao Lin finished speaking, he went into the kitchen to cook, muttering, "And it keeps getting bigger the more I feed it."

——

Lin Chaoxi later thought that Old Lin probably didn't lie.

To him, the daughter who suddenly appeared out of nowhere was probably more difficult to deal with than those math problems.

She was so troublesome, ate so much, and not only did she need his education, she also always needed his help. Whether it was chasing boys or studying, or even what to eat every day, she couldn't leave him.

Although Lao Lin did not say anything, he asked students near the window to draw the curtains during a weekend math cram school. The classroom was newly equipped with projection equipment, which made it look like it had entered a new era.

The curtain dropped and then lit up, and everyone was surprised to find that Lao Lin was actually going to show them a movie.

"Teacher Lin, don't we have class today? Do we want to watch a movie?" the students asked excitedly.

"You can take classes while watching movies. This is an educational class that touches the soul directly." Lao Lin fiddled with the equipment and a line of words appeared on the screen.

"Wow, the teacher is so fashionable!"

“Keep up with the times and keep pace with the times.”

Lao Lin retreated to the back of the classroom and sat down. In the dim light, he leaned against the blackboard, folded his arms, and looked up at the screen.

The curtain suddenly turned black, leaving only a swinging metronome. Lin Chaoxi knew that the movie had begun.

At first, she didn't know what the film was about until a soft and shy narration began.

——Perhaps the best analogy I can use to describe the experience of doing mathematical research is that of entering a dark house. Because when you enter a dark room where you can't see your hand in front of you, you will stumble into the furniture, and gradually you will know the location of each piece of furniture, and after about six months, you will finally find the switch and turn on the light. The light suddenly illuminates everything, and you can clearly see where you are.

That's a long narrative.

But the surroundings became quiet. After the curtains were drawn, there was only a little light in the classroom. Every child looked up and watched the story being told on the projection screen.

It all started with a joke by mathematician Fermat more than three hundred or nearly four hundred years ago.

When Fermat was reading Arithmetic, he wrote a lot of notes in the margins of the book, just like what happened to the books in the Sanwei University Library. On the margin of page 8, he wrote a very short note that became the most difficult mathematical problem in the world.

Simply put, after observation, he believed that, except for the Pythagoras theorem, that is, x^2+y^2=z^2, there is no integer solution n such that x^n+y^n=z^n.

He even left a note in a very naughty way, saying, "I am sure I have discovered a wonderful proof of this, but unfortunately the space here is too small to write it down."

Later, when Mr. Andrew Wells, the protagonist of the documentary they are watching now, actually proved this simple conjecture, people realized that the words left by Mr. Fermat might be a complete prank, because the level of mathematical development at that time was not enough for him to find such a "beautiful" solution.

The subsequent narration is a bit complicated. Of course, the documentary director has tried his best to make the proof process simple and easy to understand, so he only takes the framework approach to outline the arduous process of Mr. Andrew Wells proving Fermat's Last Theorem. However, those mathematical terms that are far beyond their understanding can still easily confuse people.

There were whispers in the classroom.

Many people are asking "what is this" or "what is that"...

They didn't know what those things were, but they knew very well that behind this seemingly structure was a complex problem that was far more complicated than they had imagined.

But as the arduous argumentation process continued and the mathematician finally stood in front of the blackboard and explained his entire proof process to the audience of more than 200 mathematicians, their small classroom became completely silent again.

It was June 23, 1993 at the University of Cambridge. The mathematician kept writing calculation formulas on the blackboard. Half an hour later, he put down the chalk and finally said, "I have proved it, I think I can stop."

I can stop now.

This is the end of the problem that has plagued us for centuries.

All that was left on the screen was a photo and the background sound of thunderous applause.

Although there were some twists and turns in the argument later, the classroom was extremely quiet at that time. Only the light from the projector, the flying dust, and the tiny dots of light remained.

Looking at the mathematician with a brilliant smile in front of the blackboard, Lin Chaoxi suddenly thought that this was probably the moment every mathematician dreams of.

As a boy, Mr. Andrew Wells stumbled upon Fermat's Last Theorem while doing a puzzle in the library. For the next 30 years, his dream was to solve it, and he did.

Lin Chaoxi couldn't help but wonder, in Old Lin's mind, did he also have a problem that he dreamed of solving? If so, what was it?

She turned around and looked at the person in front of the blackboard. She realized that she had never known this.