Lin Chaoxi felt that she was also a bit strange. Before she saw the "punishment", she felt anxious and complicated.

She wanted to know about Lao Lin's past, but didn't want to find out too much about her father's past.

But now, after Lao Lin's guidance and after seeing Lao Lin's past with her own eyes, she suddenly calmed down. She was a little angry, but more calm.

First of all, she believed that Lao Lin would never plagiarize academically.

Secondly, this was something Lao Lin asked her to find, and her father was so calm about it, so she really had no reason to feel uncomfortable about it.

The only question is, what exactly caused Lao Lin to be accused of "academic plagiarism" and "expelled", and whether this incident is related to the paper on the same structure published by Professor Feng.

In addition to calling the secretariat, is it possible that Lin actually called Professor Feng Deming, who was the director of the Institute of Mathematics at the time?

Lin Chaoxi took a pen and wrote down the key information, closed the yearbook that Old Lin personally instructed her to find, and put the book back on the bookshelf.

Then she stood up, turned around twice, sorted out her thoughts, and finally walked towards the door.

When she walked out of the filing room, Lu Zhihao grabbed her and asked, "What's wrong? What happened?"

"You used this sentence pattern a lot today."

"You're just too weird!"

"I'm fine." Lin Chaoxi said absentmindedly. He walked upstairs a few steps while thinking. Suddenly he thought of something and turned back to ask Lu Zhihao, "Is your school's computer room upstairs?"

"No, it's on the first floor."

"Oh." Lin Chaoxi said, turned around and walked down.

"What are you going to check in the computer room again?" Lu Zhihao hurriedly took a few steps to catch up.

"you guess?"

"Don't be like this." Lu Zhihao began to persuade her earnestly, "I know you feel bad. You don't have to tell me, but don't hold it in."

Lin Zhaoxi: “?”

"Your father is not..."

“Oh, did you see my WeChat?”

"I accidentally... accidentally saw it. I'm sorry."

"Well, my dad graduated from Yongchuan University, but was expelled from graduate school for plagiarism." Lin Chaoxi paused, "This is the material I just found."

"I believe your father would not be such a person!"

"How come you have more confidence than me?"

"Because your father taught you very well, and I have met him, he is really smart and wise... although a little sharp-tongued." The last few words were spoken very quietly.

Lin Chaoxi smiled and wanted to say to Lu Zhihao, you were right about Lao Lin, and Lao Lin didn't teach you wrongly.

——

Lin Chaoxi followed Lu Zhihao to the computer room of Yongchuan University, and Lu Zhihao used the campus card to turn on a computer for her.

The screen lit up, and Lin Chaoxi opened the academic paper library, which showed the blue and white interface that she was very familiar with.

She had used the reference library countless times, sometimes even spending a whole day in front of it, but she had never thought of looking up Lao Lin's name.

She steadied her breath, held the mouse, clicked the search tag "author", and then entered the three words "Lin Zhaosheng".

The page jumps and the cursor moves in a circle.

The titles and abstracts of the papers poured out like a waterfall.

Agricultural economics, electric power industry, biology, physics, chemistry...

After clicking on all irrelevant subjects of thesis authors with the same name, only "Mathematics" remains.

From 1988 to 1993, only one Lin Zhaosheng published seven papers related to mathematics. The publishing unit was the Institute of Applied Mathematics of National Yung Chuan University, and most of them can be confirmed to be written by Lin himself.

From graph theory in discrete mathematics to optimization problems, from the exact graph isomorphism problem to its polynomial time algorithm, finally, Lin Chaoxi saw a review of the p/np problem written by Lao Lin.

She looked at the searched papers and was silent for a while.

There is no paper in which Lao Lin was accused of academic plagiarism, but from the research context of the existing papers, it can be seen that Lao Lin has maintained a long-term interest in issues related to graph isomorphism.

Because it was a long time ago, she didn't know how to measure the academic value of Lao Lin's papers, but "citation count" is obviously an important criterion.

"The number of citations for this paper is a bit scary. It's a pity for Uncle Lin."

Lu Zhihao's voice rang out, and the address had changed from "your father" to "Uncle Lin".

Lin Chaoxi was unable to respond. In fact, “It’s such a pity” and “It’s such a shame”, she has been thinking this way since she was old enough to understand.

Now that I have suddenly witnessed Lao Lin's true academic ability, this feeling is even more real and strong.

It was so strong that countless images emerged in her mind: Lao Lin took her to sit at the table, held her hand and walked on the road, and Lao Lin told her in a dreamy tone what a wonderful subject mathematics was.

His love is so true and pure, would he really be forced to give up mathematics because of her appearance or the so-called academic plagiarism?

Would someone like Lao Lin give up?

Once, when she showed Lao Lin the test questions for the modeling competition that Pei Zhi wrote on the blackboard, Lao Lin seemed to be very familiar with Professor Zeng and Pei Zhi's research field.

Later, he knew all about p/np issues.

Now, there is the paper that Lao Lin was accused of plagiarizing and the paper that Professor Feng published on Arvix; the reason why Professor Zeng strongly opposed this paper; and the "academic circle" that she had never been involved in...

All the clues made Lin Chaoxi have a mysterious belief - Lao Lin might have given up mathematics for some reason, but maybe he never gave up?

She reorganized her thoughts again, downloaded the seven papers first, then opened arvix and found Professor Feng Deming's graph isomorphism paper.

The paper was written entirely in English, and she read it carefully from beginning to end. There were many professional terms that she was not familiar with and the proof process was completely incomprehensible to her, but she looked up a few words and read the summary several times, and roughly understood that this paper's argument for the graph isomorphism problem was an NPC problem.

It was lunch time, and Lin Chaoxi was immersed in finding the problem. When she looked up again, she and Lu Zhihao were the only ones left in the computer room.

"What's going on? You have to hurry up. The graduation ceremony is still an hour away. Why don't we stop checking and go to your school first? Pei Zhi is waiting."

Lu Zhihao kept talking a lot, looking anxious. Lin Zhaoxi pressed the Enter key and said to him, "You go first."

"Ah?" The boy was stunned: "Isn't this your graduation ceremony?"

"Yes." Lin Chaoxi said as he began to look for more connections between graph isomorphism and the p/np problem.

There were so many related academic papers that she was at a loss as to where to start.

"What are you talking about?" Lu Zhihao said, "Hurry up, we can check these things anytime, don't delay the graduation ceremony."

"It doesn't matter." Lin Zhaoxi narrowed his eyes and tapped the mouse unconsciously, thinking about where the key to the problem lay.

Just then, she saw an academic news.

——A quasi-polynomial-level algorithm emerged for the graph isomorphism problem, and a major breakthrough was made in the p/np problem, which is the most important achievement in computer theory in the past 10 years.

Lin Chaoxi touched the mobile phone on the computer desk, and even the screen was lit up.

She looked at Pei Zhi's name on the WeChat conversation interface. Besides Lao Lin, there was definitely another person in the world who could answer his questions immediately.

However, she pursed her lips and finally turned off the screen.

Since all the questions come from Lao Lin, they should be answered by Lao Lin.

She packed up everything and sent it to her own email, then closed her browser and turned off her computer.

"You go to our school by yourself. I have something to do." She patted Lu Zhihao on the shoulder and said.

"Where are you going?" Lu Zhihao shuddered.

"I'm going to have dinner with my dad." Lin Chaoxi interrupted and sent a WeChat message to Lao Lin - "May I have the honor of inviting you to have lunch with me at noon today and ask you some academic questions?"

Lu Zhihao: "Then shall we go together to see Pei Zhi off?"

Lin Chaoxi paused, thought for a moment and said, "It's just lunch, how can it take so long?"

——

There is a noodle shop next to the Municipal Hospital. It is always crowded at noon, and it takes a lot of effort to grab two window seats.

When Lao Lin arrived, the noodles and side dishes had already arrived, except for one serving of golden and crispy deep-fried pork chops.

Outside the window, the sycamore trees cast dark green shadows. Lao Lin held a large cardboard box, put it on the ground, and sat down.

"You've grown up and know how to respect your father." As he spoke, he took out his chopsticks and picked up the golden pork chop.

Lin Chaoxi was quick-witted and quick-handed. He stuck it with the tip of chopsticks and wrestled with Lao Lin.

"Zhang Xiufen, Li Anan, Chen Ziran, Liu Liu, who among them is selected?" She called out four names in one breath, observing Lao Lin's reaction.

It was a list of staff members in the secretariat of the Institute of Applied Mathematics at Yongchuan University in her little notebook. In parentheses, she chose the one whose name looked female.

"What?"

"It can't be Wang Qiang and Li Zhigao, right?!"

"Who is this talking to? Is my Alzheimer's getting worse?"

Lao Lin's expression didn't seem fake.

"Oh, it's okay." Lin Chaoxi silently eliminated her initial guess in her heart. Her mother should not be among these people. "Then you are not allowed to eat!" she said.

"Comrade Lin Chaoxi." Old Lin suddenly spoke in a low and earnest voice.

"Ah?" Lin Chaoxi's heart skipped a beat.

"You may have forgotten one thing. Even if you don't treat your old father to a golden steak, I have the money to buy it myself."

Lin Zhaoxi: “…”

Lao Lin raised his hand and signaled the waiter to come over.

Lin Chaoxi let go of his chopsticks and asked again while Old Lin was happily picking up the steak: "Proving that graph isomorphism is an NPC problem, how important is it in solving the P/NP problem?"

Lao Lin was stunned for a rare moment, but recovered after a second: "Wow, you have been very thoughtful lately."

"How do you know?"

"Your ability to analyze problems is one-third of that of your father." Old Lin only took two bites of the steak, and his mouth was full of oil. "I won't ask you what those names mean. Just tell me, how did you connect the matter of your father being fired to the p/np issue?"

"Because graph isomorphism is relevant to this problem..."

"Classmate Lin Chaoxi." Old Lin chewed on a large steak and shook his chopsticks. "The graduation thesis that my father was suspected of plagiarizing is called "Theoretical and Methodological Research on Graph Isomorphism Verification". This is first of all a graph theory problem. This thesis cannot be found on the Internet. How did you connect it with p/np? Is there something missing here?"

"..." Lin Zhaoxi was speechless. She coughed lightly and said, "Then I will start to confess."

"please."

"After the modeling competition, I went to the mathematics department office and saw Professor Zeng and another teacher discussing a problem very seriously. I heard a conversation about something like there was a problem with the proof framework. They later asked me to copy a document, but Pei Zhi directly intercepted it without letting me see the content, and also reminded me of the problems in the 'academic circle'."

"Search for Snail." Lao Lin nodded, "We still need some."

"Later, I heard that there was a feud between our university and the Department of Mathematics at Yongchuan University. Professor Zeng recently opposed Professor Feng's paper proving that graph isomorphism belongs to the NPC problem, so I put these issues together."

Lin Chaoxi finished speaking and sat up straight: "Teacher Lin, I have finished answering, now please answer."

"Is that so?" Lao Lin smacked his lips. "It's actually very simple. If the exact graph isomorphism problem is proven to be an NPC problem, and someone finds a polynomial time algorithm for it, then p=np."

Lao Lin was chewing on a large pork chop and speaking in his usual nonchalant tone. There was a lot of noise around them, and the customers in the noodle shop were still shouting "check out", but Lin Chaoxi felt that the surroundings suddenly became quiet.

"This means the solution to that problem. It also means that human civilization will experience a new, unprecedented, explosive development," Lao Lin said slowly.

Lin Chaoxi could smell the aroma of hot food from the noodle shop. Everything seemed to be normal, but she couldn't help but feel deeply shocked in her heart.

She reluctantly placed her chopsticks on the bowl and heard the very faint sound of the porcelain being hit, and her own voice: "Is this why you study graph isomorphism?"

"Those who are interested in the p/np problem and try to climb to the top are never just Professor Zeng, Professor Feng, or Pei Zhi." Lin Zhaoxi looked at her father and suddenly felt that she was really stupid. "You have always been one of them, right?"

Lao Lin laughed: "Ah, you finally found it."