Chapter 10 Library At six o'clock in the evening, the sun is not so scorching, and it feels warm and comfortable on the body. At this time, several nearby streets have not been renovated yet, and walking on the street makes people feel crowded and warm. Xu Qingzhou walked briskly and found the district library along the route he remembered. He flipped through the natural science section for a few minutes and found a copy of Gilbert Strong's "Introduction to Linear Algebra", which he was familiar with and he took it out just for nostalgia, as well as Gauss's work on calculus and geometry, "A General Study of Surfaces". Halmos's "Naive Set Theory". The first two are Chinese versions, and the latter is the original English version. His mathematics skills are quite strong, but they are limited to certain areas, such as mathematical physics equations related to quantum mechanics, linear algebra, complex functions, etc. He has not been exposed to systematic research in advanced mathematics. For him, mathematics was just a tool, not the main research direction. It was not until he encountered a large number of computational problems in his research and his computing ability was stretched to its limits and he had to ask mathematicians for help that he realized that physics is inseparable from mathematics. The study room on the first floor was packed, and Xu Qingzhou went up to the second floor with three books in his arms.
The sharing economy had not yet taken off at that time, let alone the popular shared study rooms, so there were usually not many seats left in library study rooms during holidays. Sure enough, there were fewer people on the second floor, but there weren't many seats either. Most importantly, there were two people chattering, oblivious to the people around them. The third floor is finally better. Looking for a seat near the window, Xu Qingzhou was a little surprised when he saw the figure by the window. By the window, the girl had delicate features, a straight nose, round red lips, crystal clear eyes under thick eyebrows, delicate collarbones, smooth and delicate exposed skin, and soft long hair draped over her shoulders. The breeze blew through the hall, lifting a few strands of fine hair on the girl's forehead. She lowered her head, tapped the pen lightly, and frowned slightly. Wow~ we met again. He and Song Yao are really destined to be together. As if she noticed someone was looking at her, Song Yao raised her head, and the moment she met Xu Qingzhou's gaze, a hint of surprise flashed across her eyes, but quickly disappeared. Xu Qingzhou nodded and greeted her, then sat down opposite her with a book in his arms. Was there no empty seat around? Yes, but it was better to look at a beautiful woman while reading a book than to smile at Big Brother. Song Yao was very quiet, doing a math test. She went home and changed into a white dress, looking pure and lovely, but she also had a cold and aloof temperament that kept people at a distance. Sitting opposite her, Xu Qingzhou could even smell a faint fragrance. After Song Yao graduated from college, she went abroad to study. There was no news from her since then. She didn't even attend a class reunion. Many classmates regretted that they didn't get to see the campus beauty of Song University again. Putting away his emotions, he opened the book "Naive Set Theory" in front of him and began to read it carefully. On the other side, Song Yao was stumped by the 16 fill-in-the-blank questions. She decided to relax for a while and began to secretly observe Xu Qingzhou. He was absorbed in reading. The book on the right, Introduction to Linear Algebra? The other one, an English book, I didn't recognize it. Xu Qingzhou wasn't following me, was he? But he was taking notes. Linear algebra, I heard from Lao Liao that this is a knowledge point that can only be learned in college. Is Xu Qingzhou studying it now? Song Yao's mind was full of question marks. What should she do? She was curious and wanted to ask. It can be seen that Xu Qingzhou was very serious, but she still gave up.
The evening sunlight reflected through the glass and sprinkled on the edge of the desk. The entire reading room was filled with golden light. Song Yao was still working hard on math problems. After an unknown amount of time, Xu Qingzhou felt someone poking his arm. When he looked up, he saw Song Yao looking at him and asked in a low voice: "Xu Qingzhou, can you do this question?" In her opinion, Xu Qingzhou's mathematics was average, but after seeing the books he read, she changed her mind. Xu Qingzhou took the test paper. [The function y=f(x) defined on R, if for any unequal real numbers xx, f(x)-f(x)\xx＜0 and x, y satisfy the inequality f(x-2x)+f(2y-y)≤0, the graph of the function y=f(x-1)] Function analysis questions are indeed difficult for high school students. "Lend me your draft book." "it is good." He wrote it very carefully, listing every step. Two minutes later. Xu Qingzhou handed the draft to Song Yao. 【According to the question, we know that when the function xy≥2(xy), 1, xy=0.】 After reading it, Song Yao was shocked. When did Xu Qingzhou become so good at math? She looked at Xu Qingzhou suspiciously, but found that he was already reading a book with his head down. He is so cold, even colder than her. Song Yao pursed her lips, suppressed the little resentment in her heart, and devoted herself seriously to the ocean of mathematics. Time passed by minute by minute. At ten o'clock in the evening, Xu Qingzhou closed the book and looked at Song Yao opposite him, "I'm leaving." "Well, I'm leaving too." Song Yao looked at her phone and started packing. Xu Qingzhou stood up and put the three books back to their original places, only to find that Song Yao was actually waiting for him next to him. The borrowing procedure in the library is very troublesome now. He needs to find a lot of information, and it is troublesome to borrow it back and forth. Anyway, it is only ten minutes away from here, so it is better to read it here directly. The two came out of the library. "Xu Qingzhou, the college entrance examination is coming soon, aren't you going to review?" Song Yao asked herself the question that had always puzzled her. "I'm almost familiar with the content of high school, so I'll read some extracurricular knowledge to broaden my horizons." Xu Qingzhou is familiar with the old streets around him. If he remembered correctly, the community on the left would be demolished next year, and the others would be renovated in the next few years. When I came back from my freshman year, there were holes everywhere, just like the battlefield in Syria. Song Yao suddenly found Xu Qingzhou in front of her so strange. After following him for a while, she asked, "There's one thing I don't understand. With your ability, you can definitely achieve both fame and fortune. Why do you keep suppressing your points and being an unknown person?" "There are three types of people in the world: ordinary people, geniuses, and gods. I belong to the last type. In order not to overshadow the brilliance of ordinary geniuses like you, I choose to hide myself." Song Yao was so angry that her teeth ached. What did she mean by an ordinary person? She was also very powerful, okay! She wanted to refute, but found that Xu Qingzhou's attention had already been to a rice noodle shop next door.
Yes, after thinking for several hours, Xu Qingzhou was really a little hungry. However, he thought of a more serious problem. The pockets of the clothes I just changed into are cleaner than my face. He looked at Song Yao and invited her sincerely: "Would you like to eat some rice noodles? I'll treat you." "Let me treat you. Thank you for explaining the questions to me." Song Yao shook her head. "Okay." Xu Qingzhou agreed readily and strode towards the store. "The taste of this store is very authentic. Maybe they can open a branch in a few years." He remembered that the neighborhood had been demolished, and the owner actually opened four or five chain stores. He had been to one of them, and the food was not very good. Song Yao stood there in a daze, and suddenly had the illusion that she was being tricked. (End of this chapter)