"Hurry up, we're going to be late!"
Wang Zheng was at the forefront, his backpack strap slipped down to his elbow, making a slapping sound beside him as he ran.
Li Yuan followed behind him, his glasses almost slipping off his nose.
Zhou Hao brought up the rear, glancing back as he ran, as if to check if anyone was chasing them.
Today is the first day of final exams.
In the spring semester of freshman year at Peking University University's School of Mathematical Sciences, the exams are Mathematical Analysis in the morning and Higher Algebra in the afternoon.
The three of them crammed last night, studying until midnight. They agreed to study a little longer before going to sleep, but someone started it by saying, "Let's play a round," and they ended up playing until 2 a. m.
When they arrived at the Yucai Building, the three of them originally wanted to rush in, but they found that there was a small group of people blocking the way.
There were twenty or thirty students standing in the corridor, surrounding one person, while a teacher stood by, smiling and trying to mediate.
Wang Zheng stood on tiptoe to take a look, but couldn't see clearly who was surrounded.
Li Yuan squeezed through to take a peek, then abruptly turned back.
"It's Brother Che!"
Cheng Che stood in the middle of the corridor, wearing a hat but no mask, holding a pen and signing a girl's notebook.
There were a few boys standing nearby, one of whom was holding up his phone, clearly wanting to take a photo with them.
He signed one book, then took the next, moving quickly, but his smile never faded.
The proctor stood to the side and clapped his hands. "Alright, alright, those who have signed, hurry up and go into the classroom. There are still five minutes left. Come back after the exam; Cheng Che isn't going to run away."
The surrounding students chuckled, then obediently dispersed.
Cheng Che breathed a sigh of relief, turned around, saw his three adopted sons, and smiled, "You're so late."
Wang Zheng rushed up, his expression shifting from anxiety to a complex kind of admiration:
"Godfather! When did you get back? I watched the Wimbledon final! That serve, 231! You even dented the advertising boards!"
Li Yuan nodded beside him, his tone also very excited:
"We wanted to message you last night, but we didn't because we didn't want to bother you. We ended up studying until midnight, and we were so tired and excited that we couldn't concentrate at all."
Zhou Hao added, "Then we played League of Legends for a while, to balance work and rest."
Cheng Che glanced at him. "Work-life balance?"
All three of them simultaneously looked away.
Once inside the classroom, we sat down according to our student ID numbers.
When the exam papers were handed out, Cheng Che glanced at them.
Mathematical Analysis, six major problems.
The first question tested the completeness of real numbers, the second the continuity of multivariable functions, and the following questions involved series and integrals.
After reading it the first time, he had an idea in mind.
These questions were not difficult for him.
With an IQ of 90 and the ability to " Comprehension by Analogy," he didn't miss a single book he was supposed to read in the past six months, even though he hadn't attended many classes in the classroom.
He picked up his pen and began to write.
The pen tip didn't move quickly across the paper, but it never stopped.
Wang Zheng, who was next to him, was still biting his pen cap while looking at the first question, Cheng Che had already turned to the second page.
The first day of exams ended quickly.
The afternoon's advanced algebra was similar, covering matrix diagonalization, linear space isomorphism, and quadratic forms—each problem was something he was familiar with.
When they handed in their papers, Wang Zheng's face was a little green, Li Yuan adjusted his glasses with a calm expression, and Zhou Hao slumped over the table, looking completely drained.
"Dinner tonight?" Cheng Che put his pen back into his pencil case.
Wang Zheng raised his head, his expression changing from "utterly hopeless after finishing an exam" to "I'm still alive": "Eat! I have to eat!"
"Then you guys go and grab seats first, I'll go find Professor Liu."
The office building of the School of Mathematical Sciences is located next to the Science Building and has three floors.
Cheng Che knocked on Professor Liu's office door, and a voice from inside said, "Come in."
Professor Liu sat behind his desk, several papers spread out in front of him, and reading glasses perched on his nose.
Seeing Cheng Che come in, he took off his glasses, leaned back in his chair, and smiled.
"Are you done with the exam?"
"The exam is over."
Is it difficult?
"It's not difficult."
Professor Liu nodded, his expression conveying a sense of "I knew you would say that."
He pointed to the chair opposite him, gesturing for Cheng Che to sit down, then picked up his teacup and took a sip.
"You played very well at Wimbledon," he said, his tone calm, but beneath that calmness lay a genuine sense of satisfaction. "I watched the final; Alcaraz was completely outmatched by you. Grass and clay are different; it's truly remarkable that you adapted so quickly."
Cheng Che smiled and said, "It's alright. Grass is faster than clay, but the way you exert force is about the same."
Professor Liu glanced at him, shook his head, and stopped dwelling on the tennis matter.
He leaned back in his chair, then changed the subject. "You told me before that you were writing your second paper. What's the title?"
"Explicit Optimization of Effective Constants in the Baker's Method and Its Application in Specific Equations."
Professor Liu paused for a moment, his hand holding the teacup still.
He put down his teacup, sat up straight, and his expression was much more serious than before. " The Baker's Method?"
"Hmm," Cheng Che said, "Using Baker's technique for estimating the lower bound of linear forms, we've calculated the effective constants more precisely. Then we'll practice with a few classical equations to verify the method."
Professor Liu stared at him for a few seconds, then slowly exhaled.
He took off his reading glasses, placed them on the table, and spoke with a complex mix of emotions:
"When I read Baker's paper back then, I thought the method was elegant enough. The idea of optimizing the constants and then verifying it with specific equations... was very solid."
He paused for a moment, then asked, "How's the progress?"
"Not bad," Cheng Che said. "The draft is over thirty pages long, and the main derivations are all working without any major obstacles."
Professor Liu paused for a moment, then chuckled.
There was a hint of helplessness and a hint of pride in that smile.
"Okay. You can submit your manuscript yourself now. The Annals of Mathematics has a very high opinion of you. In the reviewer's feedback on your last paper on the Integer-Coefficient Polynomial Root Distribution Conjectures, there was a sentence saying, 'Looking forward to the author's follow-up work.' You can submit it directly; I don't need to be the corresponding author."
Cheng Che nodded.
Professor Liu looked at him, as if he wanted to say something, but in the end he just waved his hand. "Go on, take a good rest for a couple of days after the exam. The thesis isn't urgent, we'll talk about it after you finish the exam."
Cheng Che stood up and walked to the door, but Professor Liu called him back from behind.
Cheng Che.
He turned around.
Professor Liu sat in his chair, put his reading glasses back on, and flipped through half of the paper in his hand. He didn't look up, but a smile played on his lips.
Congratulations on your Wimbledon Champion!
Cheng Che smiled, pushed open the door, and left.