Jiang Wenyuan was praised by Shen Guofeng a little fluttering. He took out a letter of appointment from the Institute of Mathematics at the University of Copenhagen and Henriel Brown. Teacher Booth's letter to Shen Guofeng. After Shen Guofeng finished reading Teacher Booth's letter, he stared at Elder Jiang Wen for a long time before saying:

"It turns out that Professor Jiang is a world-class mathematician, and I am really fortunate to know you! It is no wonder that these mathematical problems came to Professor Jiang's hands without much effort. ”

Jiang Wenyuan said modestly: "You are too complimentary! It so happened that when I was in college, I majored in partial differential equations, so I was able to solve them. There are many branches of mathematics, including geometry alone: plane geometry, solid geometry, analytic geometry, projective geometry, differential geometry, topological geometry, Riemannian geometry, and so on. A mathematician can only be exposed to and familiar with mathematically limited subjects. As the saying goes: interlacing is like separating mountains. Even if the great math master is not involved in the math topic himself, some simple math problems may not be able to be solved. I'm kind of a blind cat and a dead mouse, and I just happened to run into it, and there is nothing remarkable about it. ”

"Professor Jiang, you have done my friend a great favor, and you will be leaving Kunming soon, so I will treat you today. I'll take you to a fun place to have fun and celebrate! ”

Shen Guofeng pulled Jiang Wenyuan out of school, called two rickshaws, and drove them to the Paramount Ballroom in the bustling downtown area of Kunming to get off. Shen Guofeng gave the car money, and he wanted to pull Professor Jiang in. Jiang Wenyuan looked at the colorful neon flashing on his head and asked suspiciously, "Mr. Shen, the good place you took me to is here?" ”

"Yes, the girls here are all as beautiful as fairies, one is beautiful and the other is beautiful. It's really a fairyland on earth. ”

"It's too expensive."

"Haha, it's not a waste at all. That's my friend's money. Do you know? He offered a big reward for the answer. He paid enough money for us to come here for a month. ”

As he spoke, Shen Guofeng took out a large stack of banknotes from his purse and stuffed it into Professor Jiang's hand and said, "This is your labor fee." ”

With money, Professor Jiang seems to have confidence. He straightened his clothes. followed Shen Guofeng into the Paramount Ballroom. I found a seat next to the dance floor and sat down.

Shen Guofeng brought a bottle of French red wine from the bar and drank with Professor Jiang.

Professor Jiang sipped his wine and took in his surroundings. The ballroom is quite large, richly decorated, and extremely luxurious. There is a group of musicians standing next to the dance floor, playing soft music. intoxicating; On the dance floor, men and women dressed in fashionable clothes held hands around their waists, dancing briskly to the beat of the music. Jiang Wenyuan hadn't felt such an atmosphere and enjoyed such a life for a long time. As a little professor, he dared to imagine such a luxurious life, and he didn't know that there was still such a place for pleasure in Kunming City

At this time, after a dance, the lights came on. The dance partners walked out of the dance floor holding hands. Each returned to his seat. Shen Guofeng stood up from his seat, beckoned to a woman in an emerald green cheongsam not far away, and slapped his palms a few times. The woman came over and sat down next to Professor Jiang. Shen Guofeng poured a glass of wine and handed it to the woman. Then he introduced to Professor Jiang:

"This is Miss Peony, the number one dancer in the Paramount Ballroom."

"This is a graceful and elegant Chinese talent, a professor at Yunnan University, and a teacher Jiang Wenyuan."

Miss Peony took out a cigarette from Kun's bag and lit it, spit out a beautiful smoke ring and said, "Oops! It turned out to be a great intellectual, long admiration, long admiration! I'm so glad I met you. ”

The voice was as crisp as silver.

Jiang Wenyuan said modestly: "What kind of great intellectual? Don't listen to Mr. Shen's nonsense, I'm just a poor teacher. I can get to know Lady Peony. Such a beautiful woman is the blessing of my life. ”…,

Jiang Wenyuan didn't dare to look at this woman, and his gaze quickly swept over her face. He only felt a light in his eyes. An angelic smile bloomed on her beautiful face, which was very cute. It is like seven fairies floating down from the heavenly river. Jiang Wenyuan only felt that his heart was surging, and he was so excited in his heart.

At this time, Peony generously stretched out her white and soft hand and gently held Jiang Wenyuan's hand and said, "Can Professor Jiang enjoy the light and dance with me?" ”

Jiang Wenyuan pushed and said, "I haven't danced for a long time, I'm afraid I can't dance well, so let Mr. Shen dance with you." ”

"What are you talking about, the peony girl tells you to jump, you jump. You haven't jumped for a long time, and you should ask the peony girl to train you. Otherwise, when you go abroad in the future, you won't be able to dance, and you will tell jokes to foreigners! ”

Shen Guofeng pushed Jiang Wenyuan onto the dance floor.

The dance music is lingering, the lighting is blurry and illusory, and there is a feeling of drunkenness and dreaming of death. Peony pressed his body closer, and his chest pressed against his blouse, and his fluffy hair gently swept over Jiang Wenyuan's face with the rhythm of the dance, making his heart ripple, as if there was a sweet and seductive breath tightly surrounding him, making him suffocate with pleasure. Jiang Wenyuan was a little uncontrollable, his steps were chaotic, he stepped on the wrong beat, and almost stepped on Peony's feet several times, which made him very embarrassed.

"Professor Jiang, don't panic, relax. Keep up with the pace. Peony gently encouraged, and her eyes were filled with incomparable tenderness. Jiang Wenyuan was intoxicated.

The music stopped. Jiang Wenyuan was so tired that he was sweating profusely. The peony's face also bloomed as a peach-like crimson, panting, and sweat stains were also stained on the emerald green cheongsam.

Jiang Wenyuan apologized with an embarrassed face: "I'm really sorry, I'm not dancing material, I'm like an ugly duck struggling around, and I'm tired of you." ”

"Professor Jiang, I can see that you have a talent for dancing, and you used to dance well, but you haven't danced for a long time, and you are unfamiliar, so you will come often when you have time in the future, and it will be okay to dance more."

Peony asked the waiter for a glass of soda and sipped it, comforting Jiang Wenyuan.

At this time, the dance hall played the dance music of tango. Peony invited Jiang Wenyuan to dance again. Jiang Wenyuan waved his hand and said that he was too tired. Shen Guofeng stood up and took Peony's hand, came to the dance floor, and danced. Shen Guofeng's dancing is not bad, as if he has been professionally trained. He partnered with Peony and had a very tacit understanding.

The two danced exquisitely, and their gestures were very beautiful, which made Jiang Wenyuan secretly applaud. After watching it for a while, Jiang Wenyuan was a little tired. He leaned back in his chair and slowly closed his eyes. At this time, those mathematical symbols jumped into his mind one by one like tadpoles, jumping in an orderly manner with the music, forming beautiful mathematical formulas, and constituting a very beautiful fantasy pattern in the mathematical kingdom. Professor Jiang's cerebral cortex became active. Ideas and inspiration were stimulated. He opened his eyes. Immediately, he took out a pen and paper from his pocket, and carefully calculated the formula he had just thought of.

At the end of the song, Shen Guofeng didn't know where he had gone, and Peony returned to his seat alone. Peony saw Jiang Wenyuan's serious and persistent calculating math problems, and became angry: "This is the dance hall. It's not your college class, what else is it, it's really a big storm. ”

As she spoke, she snatched Jiang Wenyuan's manuscript paper and tore it to shreds. Jiang Wenyuan was enraged by her sudden move, and all the inspiration that had just come to him was gone. He angrily pointed at Peony and wanted to scold: "You, you, why did you tear up my manuscript paper." It's something I didn't come up with with a long time, and I was ruined by you all at once. He thumped his chest with excitement.

As soon as Peony looked casual, Jiang Wenyuan gritted his teeth and stomped his feet, and really wanted to rush forward and beat her. Peony said unusually seriously: "Professor Jiang." You're here to write and draw. The owner of the ballroom thinks that we don't take good care of the guests and will fire us, so you should think about it for me. Peony turned her back and wiped the tears from the corners of her eyes with a handkerchief. A pitiful look made Jiang Wenyuan's heart soften. The clenched fist relaxed. Peony sobbed and said, "I'll compensate you." No matter how expensive your manuscript paper is, we can afford to pay for it. ”…,

"To put it mildly, that's my inspiration, my heart's work! It contains the great mathematical inventions and creations of the future. That's a priceless thing, can you lose it? Jiang Wenyuan was a little nervous, and the more he spoke, the more excited he became, and the voice scared everyone around him.

Peony looked at his serious and persistent look. He smiled and bowed back, clutched his stomach and said, "What invention?" What kind of creation? Weird and scary. Ha, ha. Ha, I'm laughing, I'm laughing! ”

Jiang Wenyuan felt that talking about science and mathematics with a dancer like Peony was simply playing the piano to a cow, and it was a waste of effort. So, he turned around and left the ballroom in a huff. Peony stepped forward and took Jiang Wenyuan's hand and said, "Professor Jiang, don't go!" Little girl is not talented, you things, I will too. ”

Peony's voice was not loud, which frightened Professor Jiang a lot. Jiang Wenyuan hurriedly turned around, stared at his eyes full of doubts, and said in a disdainful tone, "You will too!" What kind of international joke are you playing, pretending to be a mathematician! You are a dancer with excellent posture, outstanding dancing skills, and everyone loves you, but it is difficult for you to understand the most cutting-edge, profound and mysterious things in mathematics. It's really unobstructed, and it's a big joke in the world! ”

Peony said; "I really will, you bring the paper, I'll show you."

Jiang Wenyuan shook his head, sighed and said, "Forget it, I'll go back and rethink it and calculate it again." You can count that the sun will come out of the west. ”

"You don't believe me!" Peony cried aggrievedly.

At this time, Shen Guofeng came out of nowhere, returned to his seat, and saw the two arguing, so he asked what was going on. Jiang Wenyuan told the story as it was. Shen Guofeng criticized Peony and said: "You're not right. Although Professor Jiang has broken the rules of your dance hall, you can only stop his behavior and confiscate his things, but you can't destroy the guests' things. ”

Peony said immediately: "It's my fault, it's all my fault!" I'll just pay him. There's no need to bully people. ”

Jiang Wenyuan was already angry in his heart, and when he heard this, he couldn't help sneering a few times and said:

"Don't boast about Haikou, can you compensate? It's not as simple as a piece of paper or two, it's the wisdom and inspiration of a great mathematician, a priceless gift from God, which you will never understand! ”

"Can't I try it?" Peony asked in a low voice.

Shen Zhiping took out paper and pen from his leather bag and handed them to Peony. Peony slowly lit a cigarette and inhaled it slowly, spitting out beautiful smoke rings in his mouth.

Peony finished smoking a cigarette and asked the waiter to get a cup of coffee. After a few sips, Peony picked up the pen and quickly wrote on the paper.

"Let (X,d) be a non-empty complete metric space. Let T:X→X be a compression map over X, i.e., there is a non-negative real number q