Ask yourself, does a beautiful and dazzling woman like Shangguan Rin really exist in this world?

Maybe not, maybe there is, but, Rin looks like no makeup now!

And those so-called beauties, no matter how much they sink into the fish and geese, and the country and the city, what will happen once they take off their makeup and PS......

Looking back on his life experience from childhood to adulthood, he thinks that he is not a person who does not eat the fireworks of the world, whether he has seen it with his own eyes or witnessed it in the media, thanks to the development of information technology, I am afraid that there are countless beautiful women I have seen over the years, however, now I think about it seriously, Fang Ran found that there is no woman in my memory who is more beautiful than Shangguan Rin in front of me, more charming, and even, more able to stimulate men's most primitive desires.

This is not normal, not normal at all, a voice deep inside reminds him, that he has to face up to a possibility that Rin has proposed.

But what kind of evidence is needed to prove that Rin is an alien, which is a cliché?

After thinking about it, for a second or two, Fang Ran, who has never scoffed at mentally handicapped science fiction movies and television, couldn't help but feel a chill in his heart, he couldn't help but think of those shoddy or not so shoddy Hollywood works, the evil aliens in them are either dressed in human skin or directly transformed, in short, they are all monsters that look like people on the outside and are terrifying on the inside.

So will Shangguan Rin in front of him also ......?

This kind of thought can't be easily extinguished once it appears, but no matter what, after carefully looking at it thoughtfully, Fang Ran quickly admits that he doesn't have the ability to tell if Rin is human from his appearance.

Or, isn't it a scary monster?

He couldn't see it at all.

Case......

At this time, Fang Ran had a little calculation, no matter what, if the girl in front of him was not malicious, he could ask no matter how he asked.

Conversely, what if the couch is not a human, but a monster?

Then, since he has fallen into the clutches of the devil, it doesn't matter how he asks.

"Okay. Looks like you're serious—"

"—of course."

"Then I'll be open and honest, Rin, since you call yourself an 'alien', can you first answer me a question: What is your true face?

Is it a monster, a machine, or a force field, a spirit, or something like that? ”

"W-What, do you think I look like?

With all due respect, Fang Ran, you don't seem to understand what I said just now, at least you didn't listen carefully, "No matter how you say it, it's still a little girl, and now, she is actually suspected of being a monster by the man opposite, Shangguan Rin's rare brows furrowed, and his anger was a little, but now is not the time to argue with this guy with unique thinking,

"I mean, 'We're not people of the same world,' do you hear me?

'Humans', not monsters!

Although from a biological point of view, there are always some differences, but - not monsters, but the same as the inside and the outside, keep your eyes open and see clearly, okay? ”

"Ah, don't be angry, I'm just asking......"

Is it the same on the outside and on the inside, Fang Ran was a little cold sweating.

Seriously, after getting along with Shangguan Rin for the past few days, it was the first time he saw her angry at him; The girl in front of him didn't know where the sacredness was, but Aimei's mentality was no different from that of ordinary people, so he waved his hand to apologize to Rin, and then concentrated on thinking about the core issue of the day, looking for a practical way to discern it.

If, just if, there is really an alien visitor sitting in front of you, how can you verify it?

Especially when this "alien" looks very similar to an earthling, and it is impossible to distinguish it with the naked eye......

Thinking of this, Fang Ran had a preliminary idea.

Aliens, since they can come to the earth, how can it be said that their scientific and technological level will be much more developed than the earth, then, as long as they find some technical problems from the fields he is familiar with, and see if Shangguan Rin can answer them, the problem will be solved, isn't it?

"Rin, I have an idea.

Since you claim to be 'from another world'," this statement is a bit supernatural, Fang Ran thought, the other world should not be heaven or hell, "Since you can come to Earth, then you can think that your world's technological level is much higher than the current level of Earth, right?" ”

"Well, that's true,—— yes, I thought about it too, you might as well ask about science and technology."

"Really, let me think about ......"

For a moment, Fang Ran had a little delusion, he felt as if he was facing God, asking questions like an ignorant five-year-old child, but if he wanted to say a question, it was simply easy, so he asked without thinking about it:

"Rin, can you tell me if the P/NP issue can be determined, or if P=NP is true?"

The P/NP problem, an unsolved mystery in the field of mathematics, is not well understood.

Roughly speaking, the meaning of this proposition is "If there is a problem that solves the algorithm and has a time complexity of 'polynomial', it is called problem P, and there is only a problem of verification algorithm with a time complexity of 'polynomial', which is called problem NP; can the NP problem be transformed into a problem P?" Or, if a problem can be verified in polynomial time to see if the special solution is correct, can all the solutions be obtained in polynomial time? ”

This question seems a bit obscure, but it is a principled basis for using mathematical tools to analyze and solve problems.

For example, if an NP problem can be determined to have a "polynomial-level algorithm", then it is feasible from an engineering point of view to design such an algorithm and use a computer to solve it. If, on the other hand, there is no such algorithm, which is a terrible amount of computation to solve this problem, then in principle, even if there is a fast computer, there is little hope of solving such a problem.

Ever since the P/NP problem was identified, humans have been trying to solve it, but, at least as far as we know, there has been no answer until now.

casually asked P/NP, and when the words came out, Fang Ran suddenly felt a little inexplicably excited.

This excitement probably comes from a kind of conjecture, if Shangguan Rin is really an "alien" and not a whim, then if she gives an answer, how epoch-making it will be to promote the algorithmic research and problem solving of the human world!

However, this excitement lasted for a few seconds, and it was washed away by Rin's answer:

“P/NP…… Is it an 'algorithmic determination problem'?

Unfortunately, this is a question that I, and my civilization, cannot answer, because we don't know the answer either; Although, from a positivist point of view, we tend to think that 'there is no such judgment algorithm'. ”

"Oh...... Is it. ”

This little girl, she really knows the P/NP problem!

This was Fang Ran's first thought, and then, there was a faint disappointment, although he knew that there was very little hope.