The return journey is long, lined with thick green plane trees.
Lin Zhaoxi was walking in the shade of a tree with her backpack on her back. It is a long distance from the hospital to the lecture hall of the university town, and you can take a taxi or take a bus. But after tossing around in the hospital all afternoon, the time for the lecture of 0 Basics University Mathematics was already over, so she was not in a hurry and walked back slowly.
The summer wind is soft, boys and girls pass by, and those black hair flying around the skirts make people want to eat ice cream.
Lin Zhaoxi licked the corner of her mouth, turned left, and walked into a convenience store.
She stood in front of the dazzling array of freezers for a while, thinking whether to eat a strawberry-flavored Baxi or a crispy Menglong.
The sliding door opened with a ding, and Pei Zhi walked in.
Lin Zhaoxi and him looked at each other, and their first reaction was that it was a hell of a fate.
Pei Zhi was on the phone and saw her, and after nodding politely, he went straight to the water tank. With a clear goal, he took a bottle of mineral water and walked towards the cashier. After the beep of the cashier, he paid the bill and left.
That was probably a scene that was constantly replayed in Lin Zhaoxi's mind later on.
From the beginning to the end, Pei Zhi was talking on the phone. He used low and fluent English, speaking content that she could not understand at all, and because of his modest and casual attitude, there was no boasting at all.
He left the checkout counter, turned his head slightly, clamped the phone with his shoulder, freed his hands to unscrew the bottle cap, and took a big sip.
She was obviously right next to him, but he didn't intend to find someone to do it for him. Even before he left, Pei Zhi still nodded to her.
Sliding the door open and close, he left the convenience store and walked into the shade of the dense green trees.
Lin Zhaoxi looked at the boy's handsome and straight back, and watched him walk into the distance until he disappeared.
The cool air conditioner in the convenience store fell from the air outlet. Lin Zhaoxi looked away and looked at the dazzling array of cold drinks in front of her. Whether it was vc drinks or WeChat, all the girlish feelings she had or had just disappeared.
She didn't think there was any problem with Pei Zhi not stopping to hang up the phone to talk to her, she nodded her acquaintance, this is their normal distance now. Countless times in the past, she and Pei Zhi had the opportunity to pass by like this, and they all passed by like this, but it was nothing.
Lin Zhaoxi opened the freezer and replaced it with the sweetest strawberry cone to comfort herself.
—
It wasn't until she sat down in the No. 1 lecture hall and the lights dimmed that Lin Zhaoxi had a rough idea of who Pei Zhina was calling when she was on the phone.
This is the third time she saw Pei Zhi today.
The young man put on a formal smoky gray suit and white shirt with the cuffs rolled up, without a tie, looking very handsome and clear.
He seemed to have the school emblem of Sanwei University pinned to the front of his suit, and was leaning slightly, adjusting the projector with the staff in the lecture hall. He focused his eyes, and occasionally talked to the staff around him. The slides on the screen moved and stopped, and returned to the original page after a while.
—p/np and the search for the impossible
by andy howard
There are two lines of white letters on a blue background.
The speaker, Mr. Howard, is a professor of University of H, a mathematician, and a senior writer. He has conducted in-depth research on the p/np problem. The translation is Pei Zhi.
The seats under the stage were dimly lit. Lin Zhaoxi rested her hands on the seat partition. Next to her was a mobile phone that had been turned to silent mode. On the screen, the college WeChat group kept refreshing the set photos taken by the fans in the playground.
Hanamaki was wearing a jersey, and under the headlights on the set, he was shooting continuously, and his whole body was shining brightly.
Lin Zhaoxi took a last look at the phone, turned it over, and looked up.
It was six o'clock.
The academic lecture did not have any complicated opening ceremony. Pei Zhi put on the microphone, stepped onto the stage, and stood right in front of the curtain.
He bowed slightly and greeted the audience. His face was illuminated by the projector's spotlights, so his nose bridge was straight and his eyebrows were handsome.
Ning Herushui's voice flowed out: "In 2000, the Clay Institute of Mathematics announced 7 major mathematical conjectures, and offered a reward of 1 million US dollars for each difficult problem, hoping to find the answer. The peak of the summit, the solution of every problem is destined to change the development of mathematics. And the p/np problem is also among them. Today we are honored to invite Mr. Howard, a tenured professor of Mathematics Department of H University, to introduce this world-class mathematics to you problem."
Pei Zhi's introduction couldn't be more simple, and the audience applauded, and he naturally stepped aside.
There are no fangirls here.
People from all walks of life are welcome to listen to the popular science lectures. Lin Zhaoxi sat almost at the end of the hall. Looking around, she saw many gray-haired old people and young-faced students. Among them were teachers, professors, and students wearing Yongchuan High School uniforms. Everyone had paper and pens on the seat partitions, and everyone was clapping their heads up.
The potbellied Professor Howard came to the stage amidst applause. He was standing in front of the slide, and the applause gradually slowed down. He smiled and greeted everyone present, and also introduced his translator Pei Zhi in a very gracious manner.
The lecture hall was quiet again, only the light on the podium.
Professor Howard began to talk about the definition of the p/np problem. In the popular science lectures, they did not describe the complicated mathematical definition, but explained it with very simple concepts.
If p=np, it means that humans can quickly calculate the solution of any problem.
He started with the imagination of cancer treatment, and talked about a treatment that does not require chemotherapy, but can confirm the DNA of normal cells and cancer cells through DNA testing, and then produce specific proteins to effectively starve cancer cells and eliminate them from the body. Way.
This new type of treatment plan will make cancer treatment more efficient and targeted, without side effects on cancer patients, and more importantly, it will be very cheap, so that every cancer patient can afford it.
The imagination of this treatment plan first depends on an algorithm that can effectively solve the np problem, that is, p=np.
Lin Zhaoxi's simple everyday English sounds perfectly fine. With Pei Zhiwei's eloquent translation, Lin Zhaoxi can gradually see such a simple and efficient beautiful world.
She also finally understood what Lao Lin said, if such an algorithm appears, then Alzheimer's disease, which is a problem of β-precipitation-like protein precipitation, should also be cured.
A picture of cheering appeared on the slide, and all the audience began to applaud and laugh.
Only on the speech stage, Pei Zhi and Professor Howard looked at each other, showing sober and calm eyes.
The next explanation is more in-depth, from p problem, np problem to npc, from time complexity to polynomial level of time complexity, the lecture begins to extend to the real field of mathematics, Lin Zhaoxi can still understand it through Pei Zhi's translation at the beginning Some, but gradually, she felt strenuous.
Although Professor Howard has found a lot of examples to explain a lot of content, Lin Zhaoxi is very clear that she does not have the knowledge reserves to understand those professional terms. She has been away from the world of mathematics for too long, and in some respects she is not even as good as an ordinary high school student .
In the end, whether it is the speaker or the translator, their expressions are calmer and clearer.
In the end, the in-depth content was already too strenuous for her, so some bright images overlapped, and she began to lose her mind.
I always feel that there seems to be a similar picture in my memory. At that time, she and Pei Zhi were working side by side. Pei Zhi was still young, with a delicate and fair face, looking at the old man in the projection screen with a confused but yearning gaze.
Time and space reversed.
Ten years later, she was still sitting under the stage, while he was already standing on the stage.