Xueba starts with change

Chapter 322 Enlightenment of NP complete problem?
Seeing this, Chen Zhou smiled and shook his head.

He felt that Zhao Qiqi and Zhu Mingli had completely reached the realm of letting themselves go.

As for Li Li, he didn't let himself go.

One is that his personality is relatively reserved, and the other is that he doesn't have the conditions to let himself go, okay?

Ever since he was with Li Jing, he has been under Li Jing's supervision...

Turning his gaze back to the computer web page, Chen Zhou paused as he slid the mouse wheel.

It's not because of the content in front of him, but because he suddenly remembered, why is the profile picture he saw on Zhu Mingli's phone so familiar?

"Professor Zhang again?"

Chen Zhou couldn't help being a little bit dumbfounded, he still remembered what happened on the campus internet before.

But I didn't expect that Professor Zhang Zhongyuan would like to mix the campus network so much.

Is it possible to get along with the students to prove that I have always been my young self?

Not necessarily?At least that head doesn't look like...

"Design a pentagon that fills a plane without leaving gaps. How many such pentagons are there?"

This is the problem of "plane dense tiling", and it is also a difficult problem that has always plagued the mathematical community.

There are many applications of dense paving theory, such as how to maximize the use of space and save costs when stacking objects in the simplest way.

In crystallography, how to optimize the crystal structure also belongs to the application category of tessellation theory.

However, since each interior angle of a regular pentagon is 108 degrees, rather than a factor of 360 degrees, the plane cannot be tessellated, and the problem can only be challenged with deformed pentagons.

One of the 11 major events in the mathematics world is that mathematicians finally found the 15th pentagon.

This is also one of the two things that Chen Zhou is interested in.

Chen Zhou looked at the 15 patterns covered with pentagons on the webpage with great interest.

The pentagon problem is an area of ​​geometry of interest to most scientists because it is the only shape that is not fully understood.

And this 15th pentagon is also the first newly discovered pentagon that meets the conditions in 30 years.

Chen Zhou thought for a moment, then slid the mouse to see the next event of interest.

Now he is purely interested, and does not plan to buy into the field of geometry immediately.

As for another thing that Chen Zhou is interested in, it is the progress of the graph isomorphism problem.

This has always been a special problem in complexity theory.

To put it simply, it is a regular pentagon or a five-pointed star, whether it belongs to isomorphism, that is, the problem of one-to-one correspondence between points.

In the description of this matter, it is about the related papers submitted by Professor Babai of the University of Chicago in the 2014 seminar.

His work was intended to show that solving the problem requires only slightly longer quasipolynomial time than polynomial time.

His results are also recognized by most mathematicians, who believe that this will be a huge progress in this field.

At the same time, it will have implications for the million-dollar "P/NP problem".

That's right, it is the "P/NP problem", one of the seven millennium problems.

It is the same as the famous "Hilbert's 1900 questions" proposed by Hilbert at the International Congress of Mathematicians in 23.

These are the seven world-class mathematical problems announced by the Clay Mathematics Institute in the United States on May 5th, the millennium.

The prize for each puzzle is $100 million!

The seven millennium problems are NP complete problem (P/NP problem), Hodge conjecture, Poincaré conjecture, Riemann conjecture, Yang-Mills gauge field existence and mass interval hypothesis (gauge field theory), NS equation solution The existence and smoothness of and the BSD conjecture (Beh and Swinnerton-Dell conjecture).

So far, only the Poincaré conjecture has been solved by the Russian mathematician Perelman.

"Is there any enlightenment for NP-complete problems?"

In comparison, among the 11 major events, this one interests Chen Zhou the most.

After all, it is research related to the millennium problem.

Although for many people, perhaps the last of the 11 major events, that is, the case of Chen Zhou, is more eye-catching.

Regarding NP-complete problems, give a simple example.

One night, you went to a party.You're feeling awkward because the party is too big, and you're wondering if anyone you know is in the whole ballroom.

Just then, the host of the party proposes to you that you must know the lady who is eating ice cream near the dessert plate.

In almost no time, you can glance there and see that the host of the party is correct.

However, without such a hint, you'd have to look around the ballroom, checking everyone one by one, to see if anyone you knew was there.

It's actually like a thing if a person told you that 13717421 can be written as the product of two smaller numbers.

You will definitely hesitate and wonder if he is right.

However, if he tells you that 12717421 can be decomposed into 3607 times 3803, then you can quickly get the answer and verify that it is correct.

This is a simple example of an NP-complete problem.

As for the conjecture of NP-complete problems, it means that since all complete polynomial non-deterministic problems can be converted into a class of logical operation problems called satisfiability problems.

All possible answers to this type of question can be calculated in polynomial time. Is there a deterministic algorithm for this type of problem that can directly calculate or search for the correct answer in polynomial time?
It sounds simple, but verifying it is another matter entirely.

NP-complete problems are also one of the most prominent problems in logic and computer science.

Even with the rapid development of computer science, there is still no answer to this question.

Gently shaking his head, Chen Zhou threw out the messy thoughts in his mind, no matter whether it can really enlighten the NP-complete problem, he must take a look at the paper of Professor Babai.

It just so happened that he also started learning computer science today.

After returning the computer to Li Li, Chen Zhou found that Zhu Mingli hadn't come back yet, so he couldn't help but be a bit dumbfounded. What kind of secret could this be? He would rather keep it secret than run away?

"Brother Chen, that, can I ask you a question?" Li Li took the computer and said hesitantly.

Chen Zhou glanced at Li Li, then patted him on the shoulder, and said with a smile: "You just say what you have, boy? Why are you hesitating?"

Zhao Qiqi also came up and said: "That's right, Brother Chen is not an outsider, what's the matter, the two LI, are you still unfamiliar?"

Li Li smiled shyly: "No, it's not..."

Chen Zhou looked at Li Li and wanted to say something, but in the end he didn't say anything, he just asked, "What's the problem?"

Li Li took out his notebook, turned to the content he wrote today, and pointed to the formula above: "It's about the distribution deconstruction method. I've studied this part for a long time, but I still can't understand it."

Chen Zhou took a look, and a smile appeared on the corner of his mouth.

(End of this chapter)