Before going to bed that night, Shen Qi received a WeChat message from Xu Rui.
Xu Rui has been in the capital for almost a week and has made it to the men's 100-meter final at the National U19 Track and Field Games. Xu Rui will participate in the men's 100-meter final tomorrow evening at 6:30 pm.
Shen Qi knew that this 100-meter final was extremely important for Xu Rui, as it concerned Xu Rui's future.
"I'll be there at 6:30 PM tomorrow to witness your 100-meter victory," Shen Qi replied with a message before going to sleep.
The Math Camp continued the following day.
The instructor was Qian Fang, who mainly taught the section on Ordinary Differential Equations.
Apart from Shen Qi, the other 25 students were all listening to the lecture in the classroom.
Shen Qi was called to a small room of about 20 square meters, where he and Sun Erxiong were alone.
The room was a complete mess. White papers were scattered everywhere on the table and the floor, most of them covered with mathematical symbols or geometric figures. Various math books were strewn haphazardly in every corner, and rulers and compasses were everywhere. Bang! Shen Qi kicked a ruler as soon as he entered the room.
Even though it was broad daylight, the curtains inside the room were completely drawn, and the only electrical appliance in the room was a fluorescent light hanging from the ceiling.
A small blackboard stands in the corner, with white chalk marks on it—it's a drawing.
The painting is composed entirely of straight lines. Viewed from the perspective of a vertical blackboard, a corridor with its door wide open stretches endlessly, with black and white squares interspersed on the floor, like countless chessboards arranged in an endless sequence.
The moment Shen Qi saw the design, his gaze never left the blackboard.
The room was filled with the smell of smoke. Sun Erxiong stubbed out his Zhongnanhai cigarette and asked Shen Qi, "How do you think of the quality of this painting?"
"Teacher Sun, I don't understand art and can't give an evaluation from the perspective of painting art, but from a geometric point of view, I really like this drawing on the blackboard. As I understand it, this drawing seems to be a cut-off of the projection lines. Its composition is all straight lines, and the simplest lines outline the most complex existence," Shen Qi said.
"It seems you've studied perspective." Sun Erxiong smiled kindly. "Outstanding painters must have a deep Analytic Geometry, such as Leonardo da Vinci, Dürer, and Alberti. But conversely, could outstanding geometers also draw? Hmm, I think so. Shen Qi, can you draw?"
Shen Qi shook his head. "No, no, I can hardly be called an academic. At most, I can doodle, draw emojis or anime cat-eared girls and the like."
"Alright, sit down." Sun Erxiong invited Shen Qi to sit down, and then said, "Let me formally introduce myself. Besides being an instructor at the Math Camp, I am also a professor in the Mathematics Department at Yenching University."
"Hello, Professor Sun."
"Shen Qi, do you know why I called you over here alone?"
"Tell me about your life goals?"
"Of course I'll talk to you about life ideals and correct values." Sun Erxiong pulled out a magazine from a pile of waste paper, flipping through it as he spoke, "Shen Qi, you published a professional mathematics paper in the 'Mathematical Innovation Herald,' sponsored by Sun Yat-sen University. The title of the paper is 'Some New Solutions to Second-Order Linear Non-Homogeneous Differential Equation with Constant Coefficients.'"
"I've made a fool of myself before an expert, please excuse my amateurish attempt." Shen Qi was somewhat embarrassed. In front of the professors of the Mathematics Department of Peking University, his conventional mathematical paper on Ordinary Differential Equations was not a remarkable achievement, and was even considered rather low-level.
Sun Erxiong closed the magazine and asked, "Shen Qi, let me ask you this: are you a student at Sun Yat-sen University or Yenching University?"
Shen Qi firmly stated, "Of course I am a student of Yenching University."
"Then why did you submit your work to a magazine sponsored by Sun Yat-sen University, while being so indifferent to Yenching University?" Sun Erxiong's face darkened.
Shen Qi was still feeling wronged. "I... I'm not qualified! <Mathematical Research> is such a high-level journal, I'm not good enough to submit a paper to it." <Mathematical Research> is a mathematics journal sponsored by Yenching University, and it's one of the top journals in the domestic Mathematics Community.
"Hehe, it's okay, don't be nervous. I was just joking. Sun Yat-sen University's math strength is still somewhat behind our Yanda's." Shen Qi Sun Erxiong laughed instantly. "Of course, with your current math level, it will be quite difficult for <Mathematical Research> to accept your paper. But don't be nervous, after all, you're only 17 years old, not even 18 yet. You're so young, your future is limitless."
"Shen Qi, look, the other students are all receiving instruction from Xiao Qian, studying Differential Equation in depth, while you have already published a paper on Differential Equation in a professional mathematics journal. You don't need to attend Xiao Qian's classes anymore," Sun Erxiong said. "That's why I called you over alone, wanting to have a heart-to-heart talk with you, about life, ideals, and our understanding of mathematics."
"That's wonderful, Professor Sun. Talented people are common, but discerning mentors are rare." Shen Qi enjoys exchanging academic ideas with professionals.
"You must have gotten a perfect score on your essay, hahaha." Sun Erxiong clapped his hands and laughed, finding Shen Qi increasingly pleasing to the eye.
After laughing, Sun Erxiong asked, "Have you had breakfast?"
"I've already eaten: soy milk and fried dough sticks."
"Are you full?"
"I'm full. I ate six fried dough sticks and drank three bowls of soy milk. The discounted breakfast at Yonghe Soy Milk near the school gate is especially affordable."
"If you're full, do some math problems. It'll help digestion and improve your stomach health, which is good for the healthy growth of teenagers during puberty."
"..." Shen Qi thought to himself, "Why do all professors in the world follow the same formula?"
Sun Erxiong walked to the small blackboard, picked up the blackboard eraser to wipe away the chalk patterns on the blackboard, and then picked up a piece of chalk to make a new drawing.
Sun Erxiong's geometric construction skills are very solid. He can draw a standard circle without using a compass, and it looks standard to the naked eye.
Immediately afterwards, Sun Erxiong casually drew a few straight lines without using a ruler; he simply picked one up and drew perfectly straight lines.
Six straight lines form a hexagon, which is inscribed in the circle.
The six points inscribed in the hexagon and the circle are labeled A, B, C, D, E, and F by Sun Erxiong.
"Did you understand?" Sun Erxiong asked Shen Qi.
Shen Qi nodded and then shook his head. "I understand it in the Euclidean geometry sense, but I don't understand it in the Non-Euclidean Geometry field because Professor Sun's conditions are insufficient. I don't know what Professor Sun wants me to do?"
"Hehe, it's good that you don't understand." Sun Erxiong smiled habitually, then continued drawing.
In the blank space to the right of the circle and its inscribed hexagon, Sun Erxiong drew three new straight lines that intersect at a single point, which Sun Erxiong labeled as L.
"Based on the pattern on the left, complete the pattern on the Shen Qi for me. I don't care whether you use Euclidean geometry or Non-Euclidean Geometry, all I want is a correct answer. Can you do that, Shen Qi?" Sun Erxiong asked with a smile.
Shen Qi's eyebrows furrowed deeply. "Give me some time, Professor Sun, I'll do my best."
"It's alright, don't be nervous. Time and this room are all yours. You can use any of the drawing tools and references in this room. Okay, I have to go buy pork. By the way, Shen Qi, do you prefer celery dumplings or cabbage dumplings?" Sun Erxiong stuffed his wallet into his pocket and prepared to leave.
"Whatever." Shen Qi's eyes were fixed on the blackboard, and he answered absentmindedly with just two words.
Sun Erxiong was unhappy. "You can be casual about doing math problems, but you absolutely cannot be casual about eating dumplings!"
Shen Qi: "How about dumplings with chives and shrimp filling?"
"Absolutely! Wait here, I'll go to the market to buy the ingredients, and we'll have chive and shrimp dumplings for lunch." Sun Erxiong was delighted and left the house to buy the groceries.