I Just Want to Be a Quiet Top Student

Chapter 28 A variant of the Euler 7 bridge?

On the morning of July 3, the second teaching building of Tsinghua University.

The Second Church is an old building, built before 1949.

It is rumored that the Second Church often has supernatural events, commonly known as haunted.

The second teaching is never open at night. The school says it is to save water and electricity.

The highest scientific research and academic institutions like Tsinghua University are naturally advocating science. In the face of powerful scientific forces, the gods, ghosts, and snakes have only a crushed fate, and they are not allowed to become refined after the founding of the People’s Republic of China.

This season, more than half of the college students have completed the final exams, and the second teacher is vacant. This is the venue for the national preliminaries and national finals of this year’s high school math league.

At 9 o’clock this morning, the national preliminaries will be held.

There is still half an hour to start. A total of 192 players from 32 provinces and cities are on standby in 201 and 202. A total of 60 of them will qualify for the national finals.

“Actually, I am very satisfied to be able to participate in the national competition, really.” said Qi Jianhong, the youngest member of the Nanyue Provincial Number Competition Team.

Shen Qi scolded: “Qi Jianhong, you know a fart, and you can’t make it to the national finals. We are equal to a trip to Tsinghua. You think you are a member of the five hegemonies of Hubei, Hunan, Zhejiang, Beijing, and Shanghai. Signing to Qingbei?”

Qi Jianhong was not convinced: “I don’t rely on a pass, can I pass the college entrance examination to Qingbei?”

Shen Qi asked: “Do you have good grades in other subjects?”

Qi Jianhong triumphantly said: “That is, in our high school, my total score is the first in the whole grade for a long time, and I cannot lose the second place with 50 points or more. Mathematics is just my hobby, and I dominate the whole grade. It is invincible comprehensive strength.”

“You little Zhengtai is pretty awesome, but I don’t care how awesome you are in your high school, you must give me your highest level in this national preparatory test, otherwise I will beat you.” Shen Qi resolutely said To.

“You, you… so savage!” Qi Jianhong is only a few meters and five meters away, and he has no power to bind a chicken. He must not be able to beat Shen Qi, who is a few meters away.

“Actually, what can I do if I beat you? Starting from the training camp, I have repeatedly emphasized that we are a team, come from the same place, and share a common dream. I cannot beat the five of you alone, but I have a champion. Heart. And you are all spicy chicken.” After Shen Qi finished speaking, he took his stationery set and left classroom 202 without looking back.

“Shen Qi, you…you actually said that we are spicy chicken!” Qi Jianhong was ashamed and annoyed. He said to the other four teammates: “Shen Qi said we are spicy chicken, so disgusting!”

“Huh, Shen Qi is a pretense thing.”

“We are not spicy chicken, we are strong!”

“Shen Qi, Hun Dan, I must defeat you!”

“I must be higher than you in the national preparatory exam!”

“+1!”

Qi Jianhong and other five people share the same hatred, an unprecedented atmosphere of unity appeared in this team for the first time.

Six people, including Shen Qi and Qi Jianhong, were arranged in six different classrooms. It was 5 points to 9 and the invigilators began to read the competition rules: “The rules are very simple. You have 3 hours to complete the national preparatory examination papers. You must not look around during the answering process. , Please raise your hand if you have anything to do. After reading the competition rules, we will begin to issue test papers and draft papers.”

Shen Qi took the exam in Classroom 101. He got the preparatory exam papers, and first quickly scanned the three exam questions. Each question was seven points, and the paper score was 21 points.

From the provincial preliminaries to the provincial semi-finals, and then to the national preliminaries, the scores are getting lower and lower, but the difficulty is getting higher and higher.

In the first question, a pattern is drawn on the surface of the roll.

There are two small islands floating in a river. The island and the island are connected by a bridge, and the island and the river bank are connected by a bridge.

is one river, two islands and eight bridges.

Q: How can a walker walk through eight bridges at once without repeating or missing, and finally return to the starting point?

“Hey, who asked this question, did Euler allow you to do that?”

Shen Qi can see through everything at a glance. This question is a variant of “Euler Seven Bridges”. Tsinghua Eight Bridges?

The god-level master in the history of mathematics, Euler, was energetic when he was young. He liked mathematics as well as girls.

Oula fell in love with a girl in her twenties, a beautiful and gentle art teacher. He frantically pursued this art teacher and finally achieved a positive result. The two got married and gave birth to 13 children… It can be seen that Euler is not only top academic, but also has a great body.

A bright spring in 1736, Euler was waiting for his art teacher girlfriend to arrive in a park in Königsberg.

Being late is a woman’s innate attribute. Waiting and waiting, one hour has passed, and the girl who teaches art has not yet made the appointment.

Euler was bored, so he began to study mathematics. He found that there were two small islands suspended in a river in the Königsberg Park. There were seven bridges connecting the small islands and the river bank. Shuttle between the two islands.

Euler suddenly got inspiration. He proposed an idea as to whether there is a path, starting from any place, through seven bridges without omission and without repetition, and finally back to the starting point.

Later, Euler wrote this idea into a paper and submitted it to the St. Petersburg Academy of Sciences. The paper was titled “Seven Bridges of Königsberg”. Later generations also called it the “Euler Seven Bridges Problem”.

Later, Euler himself overturned this hypothesis and proved that such a path could not exist.

In order to slap himself in the face, Euler invented a new method of proof. He created a new branch of mathematics-geometric topology.

This is the pattern of top mathematicians. I am invincible. I have no opponents. My only opponent is myself. In order to defeat myself, I created a new branch of mathematics.

Two or three hundred years have passed, and Shen Qi faces a new problem, the eight bridge problem.

The original version of the Euler Seven Bridges cannot be answered. As for whether there is such a path for the Eight Bridges , we have to calculate.

Shen Qi counts up, counts left, counts right, half an hour has passed, it can’t be counted!

Whether the Eight Bridges are the same as the Seven Bridges, there is no such so-called path at all. It can pass through each bridge without omission and without repetition, and finally return to the starting point.

“The national competition is a national competition after all. Topology is very difficult to do. I can’t figure out this path, nor can I prove that it doesn’t exist.”

Shen Qi put down the pen ruler and pressed his temple vigorously.

As time passed, Shen Qi couldn’t write, he was a bit obsessive-compulsive, so he had to work out the first question and then solve the next two questions.

“Euler, Seven Bridges, Eight Bridges… By the way, why do I have to use Euler’s theory to solve variant problems based on Euler Seven Bridges, this is a trap, an endless loop!”

Shen Qi suddenly realized, I thought about it, I thought about Poincaré’s network theory!

If the two broken ends are connected exactly the same as before, then this is an allowable topological operation.

The reverse is not allowed!

That’s right, the singularity of this eight-bridge diagram is at both ends, so there is no such connection at all, and each bridge can be passed through without omission or repetition.

The answer to this question is: No! Save! in!

Shen Qifen wrote down the proof process, he only took 3 minutes to complete the proof, and the thinking process lasted 1 hour.

“Whhhhhhhh 7 points, the next question.” Shen Qi sighed and burned a lot of brain cells, so tired. But the battle has just begun. He can’t relax. He must complete all the answers within the specified time and ensure that it is absolutely correct.

Even so, Shen Qi didn’t know whether his goal could be achieved eventually. I hope that the five pig teammates can give me a sigh of relief!