When Lao Lin came home from get out of class, Lin Zhaoxi had already been sitting in the yard for a long time. Although I lit mosquito coils, I still got a lot of mosquito bites on my legs.
Green smoke billowed in the yard, and Lao Lin pushed his bicycle, surprised: "What's the matter? This is, bathing and burning incense to prepare to become a monk?"
"Do you know what happened to Pei's family?" Lin Zhaoxi raised her head and asked.
"What?" Lao Lin parked his bicycle, took off the supper hanging from the faucet, and brought it to the stone table in front of her.
Those were two servings of roasted cold noodles. Lin Zhaoxi broke open the disposable chopsticks and poked them.
"I got an injection when I went to the hospital today..."
"Fighting again? Your parents even took you to get an injection. You're quite qualified." Lao Lin interrupted him.
Lin Zhaoxi: "What is 'again', and why did you ask Pei Zhi to hold a parent-teacher meeting for me?"
"Can't you find something for him to do?" Lao Lin opened the lid of the grilled cold noodles, "When the hospital gets an injection, what's next?"
"I saw him talking to the oncologist."
"Oh, his mother has terminal breast cancer." Lao Lin said calmly.
Lin Zhaoxi raised her head abruptly: "You know?"
In Gao Lin Zhaoxi's memory, there is no definite information about what happened to Pei Zhi, and Lao Lin never told her.
"Yeah, I know, you are the only one who doesn't care about my apprentice."
Lin Zhaoxi recalled what she was doing during the period before and after school started, but she was speechless.
"I'm sorry," she said.
"Okay, Pei Zhi probably doesn't want you to sympathize with him too much. Boys have strange self-esteem. They would rather help you, but they may not necessarily accept your help."
"So you asked him to be my parent?"
"No, let him be your parent because..."
Lin Zhaoxi listened carefully, but saw that Lao Lin suddenly knocked on her lunch box, and took advantage of her not paying attention, and directly picked up the roasted tenderloin inside.
"I said why is there nothing in mine, it's here with you." He muttered.
"dad!"
"Because you're more fun." Lao Lin said, "Just jump up and down if you tease me."
Lin Zhaoxi stared at Lao Lin, always thinking that what Lao Lin meant was that she was more interesting, so Pei Zhi lent it to Pei Zhi when he was in a bad mood.
She stared at Lao Lin, but Lao Lin lowered his head, and the only sound in the yard was Lao Lin's snorting and eating cold noodles.
Lin Zhaoxi thought, in fact, what Lao Lin said was not wrong. For a person like Pei Zhi, making him feel that he is being helped is worse than making him feel that he is needed.
His family's problems were irreconcilable and unsolvable, and they had no other choice but to be by his side.
Lin Zhaoxi looked at Lao Lin's hair, and called softly, "Dad."
Lao Lin raised his head, and Lin Zhaoxi picked up all the crab sticks in his bowl, stuffed his mouth full, and said while chewing: "Then when you engage in that graph isomorphism, you should also find Pei Zhi, and we will find some for him." It’s okay, after all, he is a once-in-a-century genius.”
Lao Lin: "Not a hundred years."
"ah?"
"After all, so am I. We're not that far behind."
Lin Zhaoxi: "..."
—
That night, for the first time ever, Lin Zhaoxi escorted Lao Lin to study by his side.
There are still 100 days until she leaves this world.
Within these 100 days, Lao Lin not only had to complete the entire wrong argument, but also overturned his own argument, and made new discoveries based on it.
Even if she has all the research results of Lao Lin in Strawberry World, she can't just copy them down and give them to Lao Lin.
What to do, she must be by Lao Lin's side, trying out the rules of the world and finding the correct method, just like solving a problem.
Lao Lin had no objection to her following her. That night, Lin Zhaoxi moved his homework into Lao Lin's study.
However, Comrade Lao Lin expressed doubts about her professionalism: "How many pages have you read on graph theory?"
Lin Zhaoxi got up straight away, went to Lao Lin's bookshelf, took out the first edition of "Graph Theory and Its Applications", and said, "I've read it all."
"Hey, it's amazing." Comrade Lao Lin gave her a thumbs up, "What about the exercises at the end of the book?"
"I've only done half of it, and there's a lot I don't understand."
"Then dad will tell you?"
"No, you're busy with your work. If I don't know how to learn by myself, you can teach me when you are free." Lin Zhaoxi simply refused, and sat down on her small table with a book in her arms.
If you open Baidu Encyclopedia and search for graph theory, the first sentence is probably like this
— As we all know, graph theory originated from a very classic problem, the Konigsberg problem.
The word Königsberg is of course not so "well-known", but if it is replaced by its other translated name-the Seven Bridges Problem. It has become something that many students have been exposed to in elementary school Mathematical Olympiads.
Generally, it appears in the "little knowledge" column of elementary school Olympiad books. The picture shows two places a and b separated by a river. There are two small islands c and d on the river, and there are 7 bridges connecting the islands with the land. .
The problem is as follows: How does a person start from any of a, b, c, and d, pass through each bridge exactly once, and then return to the starting point
At that time, many people tried and found that there seemed to be no way to do this. But that's mathematics, and whether it's possible or not, it needs to be proven.
Thus, graph theory was born.
In 1736, Euler submitted his thesis "The Seven Bridges of Königsberg" to the St. Petersburg Academy of Sciences. The island and the river bank are abstracted as vertices, and the bridge becomes the edge connecting the vertices, which proves that it is impossible to walk through 7 bridges without repeating.
While completing the solution, Euler created a new branch of mathematics—graph theory and geometric topology.
This is mathematics, you never know what kind of future will be hidden behind solving a seemingly meaningless problem.
Lin Zhaoxi finished reading another chapter, feeling emotional in her heart.
In fact, she knows very well that she can't help much in the deeper part of this field. But to her, her fate seemed involuntarily entangled with the question.
Knowing a little more, understanding a little deeper, may be able to help Lao Lin at a certain moment.
Comrade Lao Lin at the desk was still buried in his head, quietly doing his own calculations.
Tonight's study...
Lin Zhaoxi didn't help Lao Lin, not only that, but Comrade Lao Lin also read her exercise book and took the time to give her a proof.
They chatted for a while about the Seven Bridges problem, and Lao Lin said that it was just right, his elementary school Mathematical Olympiad class was about to cover this content, and asked her to explain it to the children on weekends.
So Lin Zhaoxi somehow began to think about how to take this class.
In the middle of the night, Lin Zhaoxi was lying on the bed, looking at the mosquito net.
In the dark, she desperately made herself think again about the problems in Lao Lin's proof and the few lines of drafts where he made a new breakthrough. She couldn't copy what was in her mind, she could only do it like ants moving a mountain.
Forcibly understand, and keep yourself from forgetting.
Before falling asleep, she crossed off the first day of 100 days on her mental timetable.
—
Anning Experimental High School is the best school in the entire Anning city. They have heavy schoolwork every day. They must arrive at school at 7:00 in the morning, and study at night until 9:00 pm.
Lao Lin is more open-minded, so she can do her own study in the evening as she pleases, and teacher Mei, the class teacher, also makes an exception because she is going to participate in the math competition training.
Therefore, she became the most special person in the class.
Lin Zhaoxi and Lu Zhihao were sitting in the classroom of the Olympiad training class held by the school. The time was 6:00 pm.
Just like in junior high school, she and Comrade Lu were not related because they were not in the same class. Not only that, Lu Zhihao, Pei Zhi, Hanajuan, Chen Chengcheng and Comrade Zhang Liang are all in Class 2.
And Hanamaki is already a well-known artist, with busy announcements, she will no longer participate in the competition.
"I heard you fought again yesterday?" Seeing her sitting down, Lu Zhihao raised his head and asked.
"What do you mean..." Lin Zhaoxi turned out the exercise book, but Pei Zhi hadn't come yet. Lu Zhihao, a high school student, is tall and burly. Sitting next to her is a bit crowded, which is not used to her.
"The group of gangsters in class 8 all said they wanted to fuck you, why are you acting like nothing happened?"
Lin Zhaoxi really didn't take it seriously: "We are a prestigious school, the little bastards will fuck me if they say they want to fuck me, what's the face of the school?"
"Anyway, I just heard that you shouldn't cause trouble. Our school really has hooligans who like to bully others. Be careful when you walk and cover yourself with sacks."
"No." Lin Zhaoxi was quite sure, and by the way, briefly talked about the handling of yesterday's incident with Lu Zhihao.
"Did Pei Zhilai help you clean up the mess?" Lu Zhihao's first sentence was this.
"Your adjective is very inappropriate, change it quickly." Lin Zhaoxi criticized.
"That shouldn't be a big deal." Old Comrade Lu changed the subject, as if the word "Pei Zhi" was the best guarantee, "However, have you ever thought that although those few people can guarantee that they will bully others, if Where are they looking for someone else?"
"..." Lin Zhaoxi, "What you said makes sense, but we can only do so much."
"Okay, I'm just reminding you. And I think, with Pei Zhi around, you should have frightened them too. It's probably embarrassing to speak harshly."
"Hmm..." Lin Zhaoxi opened the competition book and exercise book.
Gao Lin Zhaoxi is really serious, the questions are done neatly, and there are even questions that draw inferences from one example, and sometimes when the mood is good, he will come up with questions by himself. These are the habits she developed in the training team.
Lin Zhaoxi looked at it for a while, and the teacher walked into the classroom, and the class was about to start.
The students in the front and back rows of them also sat down separately.
Only then did Lin Zhaoxi realize that Pei Zhi hadn't come yet.
"Isn't Brother Pei coming?" She looked around, but there seemed to be no such information in her memory.
"It's too late, our competition questions must be too easy for him." Lu Zhihao looked at him strangely.
"oh."
The bell rang, and the teacher stepped onto the podium and wrote a line on the blackboard: "Hi students, what we are going to study today is Lecture 3 of the Olympiad in High School—Graph Theory Problems."
Lin Zhaoxi looked at the chalk writing on the blackboard, but what Pei Zhi had said on the phone at that time came to mind - when she was sick, she asked me not to touch mathematics again, and I agreed. After she passed away, the promises I had made to her had brought me tremendous psychological pressure and made me miserable.