The next day they went a little further. I saw several rows of houses in the distance, with red bricks and blue tiles.
There are several rows of houses, but they do not correspond completely to north and south, but are staggered. There were numbers written on the windows, and the windows in the back row looked into the rear windows in the row in front.
They observed it for a long time, wondering what number was written on the window.
There was a man who was very tall, neither fat nor thin, with strong shoulders, a mole on his face, wearing a peaked cap, a bit mysterious, with a round nose, and holding an envelope in his hand.
This mysterious man took the envelope from the last row to the front row and handed it in. Then change the numbers in the first row.
"Do you understand? What are you doing?" Zhan Guyue said.
"This is... maybe some kind of numbers game? The numbers on the window are pasted on old newspapers. The one holding the envelope is the postman, delivering the letter." Dong Chu said.
"Can you really explain that there are such old newspapers that are still being replaced? There are such postmen who deliver letters across a few rows of houses?" Liu Mozhi said.
"I'm explaining this to stop you from thinking wildly. Anyway, we don't know what's going on. If you can't figure it out, don't think about it. I'm tired." Dong Chu said.
They guessed that the man would not tell them the truth, so they ran to a nearby tree and squatted down. This tall man came out twice in the morning with envelopes and handed them to the house in the first row. Then the numbers on the windows of that house were changed.
Zhan Guyue said: "I said, Dong Chu, you are a serious student of mathematics. What do you think the numbers on this window mean?"
Dong Chu said: "Don't come to me this time. Mathematics studies formulas and methods. He only has a few numbers and can't find any rules. It may be a number riddle or a number game."
Zhan Guyue said: "Ms. Liu, what do you think?"
Liu Mozhi said: "From a computer point of view, no pattern has been found."
Zhan Guyue said: "These are several rows of houses. The numbers on each window change accordingly."
Dong Chu said, "I'll go down and ask."
He stopped the tall man and asked, "Excuse me, what are the numbers behind these houses?"
The man was stunned for a moment, but he didn't expect someone to ask him. He thought for a while and said: "When repairing a house, all parameters must be consistent. Put them on the windows and tell other maintenance workers. What is the length, height, and distance between the lights? some type of."
Dong Chu touched his head and came back to talk to Zhan Gu and Liu Mozhi. Then he said, "Do you believe it?"
Zhan Guyue said: "It's so suspicious. This town is really strange. Maybe it's the riddle given by Mr. Jiang?"
Dong Chu said: "What did Mr. Tang say before, the four-color theorem. This is one of the three major mathematical conjectures in the world, as well as Fermat's last theorem and Goldbach's conjecture. The content of Fermat's last theorem: When integers
> 2, the indefinite equation x^ about x, y, z
+y^
=z^
There is no positive integer solution. Goldbach's conjecture: Any integer greater than 2 can be written as the sum of three prime numbers. Does this correspond to the numbers on the house? "
Zhan Guyue said: "I don't know how it corresponds. It doesn't correspond, right? But it really feels like they are conducting research on a certain mathematical problem."
Dong Chu said: "Maybe it's some kind of neural network?"
Neural networks do not need to determine the mathematical equations of the mapping relationship between input and output in advance. They only learn a certain rule through their own training and obtain the result closest to the expected output value when the input value is given. BP neural network is a multi-layer feedforward network trained by error backpropagation. This algorithm is called BP algorithm. Its basic idea is the gradient descent method, which uses gradient search technology to make the actual output value of the network and the expected output The error mean square error of the value is the smallest.
The basic BP algorithm includes two processes: forward propagation of signals and back propagation of errors. The error output is calculated in the direction from input to output, while the weights and thresholds are adjusted in the direction from output to input. During forward propagation, the input signal acts on the output node through the hidden layer and undergoes nonlinear transformation to generate an output signal. If the actual output does not match the expected output, it enters the error back propagation process. Error backpropagation is to propagate the output error back to the input layer layer by layer through the hidden layer, and distribute the error to all units in each layer, using the error signal obtained from each layer as the basis for adjusting the weight of each unit. By adjusting the connection strength between the input node and the hidden layer node and the weights and thresholds between the hidden layer node and the output node, the error decreases along the gradient direction. After repeated learning and training, the network parameters (weights and thresholds) corresponding to the minimum error are determined. ), training will stop. At this time, the trained neural network can process the converted information with the smallest output error for similar input information.
Zhan Guyue said: "So, what are the numbers contained in the information he handed over? Are they weights and thresholds?"
Dong Chu said: "Maybe so."
They bypassed the bungalows and continued walking along the stone road. I walked to a store and saw several people studying models.
Each one resembles a small house, with different roofs. They removed the roof, filled it with sand, and put the sand into a measuring vessel to see what the volume was. There is a table made of stone next to it, and the others are ordinary wooden tables.
Dong Chu said: "When I think about it, it seems that I encountered these models when building a three-dimensional mathematical model."
Zhan Guyue said: "Calculate the volume, the volume of irregular shapes. Do you think this uses integral calculation, right?"
For a given positive real-valued function, the definite integral on a real number interval can be understood as the area value of the curved trapezoid surrounded by curves, straight lines and axes on the coordinate plane, a certain real value.
Dong Chu said: "Yes, they use sand to calculate the volume of the house, which is more flexible. I would like to use the method of modeling first and then calculating."
Liu Mozhi said: "I am reminded of the story of Edison and Upton."
Once, Edison gave his assistant Upton a waste glass bulb with holes and asked him to calculate the volume of the bulb. Upton took the light bulb and looked at it. He felt that the light bulb should be pear-shaped. He picked up a ruler and measured the light bulb up and down. He drew a sketch according to the light bulb, and then listed a lot of dense calculations. He calculated very seriously and several hours passed. Later, he discovered that Edison's method was simple and accurate, which was to pour water into the light bulb. The volume of the water in the light bulb was the same as the volume of the light bulb. Then pour the water into the measuring cylinder, and the volume of the light bulb was measured. volume.
Zhan Guyue said: "We also saw that the people in these towns didn't know what they were doing. Strange lakes, mountain peaks, houses, buildings, flat land, and models."
Dong Chu said: "I have been thinking that maybe it is a reality show. They do their thing, and then the people who are invited have to find the answer to the mystery."
Zhan Guyue said: "It's not a reality show, I didn't even see a camera."
Dong Chu looked around at the walls, pointed the camera at the middle, and pointed to others. "There are them in the corners, it's obvious."
Liu Mozhi said: "This is a store, and it is normal to have cameras monitoring it."
Liu Mozhi said: "Did Mr. Jiang make arrangements for the people in the town? A kind of performance art?"
Dong Chu asked, "Is it to lure Mr. Tang out?"
Liu Mozhi said: "Are these robots? They do the same thing all the time."
Dong Chu asked: "Is it possible that someone secretly gave the riddle and offered a reward, so whoever can solve it first will get the reward."
Zhan Guyue said: "Let me sum it up. There are several situations: 1. Reality show, 2. Performance art, 3. Performance art to attract others, 4. Robots, 5. Rewards for solving puzzles."
Liu Mozhi said: "Ah, I think about it more today than I did last year."
Dong Chu said: "If it's a reality show, we have to find cameras. There should be cameras everywhere. If it's performance art, then we have to ask them. They should really like mathematics. If it's a reward for solving the problem, It’s a mystery, he wouldn’t tell us if we asked him.”
Liu Mozhi said: "How many possibilities should we rule out first? Go to every place and check if there are cameras. Ask them why they do this. Are they really interested in mathematics? I don't think so."
Zhan Guyue said: "Why doesn't it look like it?"
Liu Mozhi said: "I feel it intuitively. The first feeling. Then I think about why."
Liu Mozhi looked around. The shops sold food, daily necessities, clothes, etc. Then she said: "Everywhere I went, I didn't see many books, or anyone taking a blackboard or paper to deduce mathematical formulas on it."
"Are all the math enthusiasts you see like this?"
Liu Mozhi said: "Maybe at least there is a computer for calculation."
