On August 15, Shen Qi plans to go abroad, when he will fly from China to New York and from New York to Princeton, New Jersey, to begin his overseas education career.

Now is Shen Qi's countdown to going abroad, and he is inseparable from Ou Ye.

In the 154-day countdown to going abroad, Shen Qi and Ou Ye had an in-depth discussion on the problem of when the equation x^2-ay^2=B has an integer solution.

This is a classic problem, and the person who has studied the Diophantine equation the most deeply and the most accomplished is Fermat.

The hypothesis of Fermat's theorem is written in a literature written by Diophantus, because there are so few blank spaces in the book, and Fermat is a very naughty eunuch, and the proof is not completed.

Formulate hypotheses, prove hypotheses, continue to make hypotheses, and wait for posterity to prove them.

For thousands of years, mathematicians have been obsessed with this number game.

While teaching at Princeton, Wiles spent ten years writing a paper in which he proved Fermat's Great Theorem and completed Fermat's Eunuch Treatise.

The numbers game is not over, and the Goldbach conjecture and the Riemann conjecture have puzzled number theorists for many years.

These two centuries-spanning superpuzzles are studied in ---very simple prime numbers, natural numbers that are only divisible by 1 and itself.

The ultimate proof of the ξ function model may start with the simplest Diophantine equation.

Once the ξ function model is fully proved, it is possible that Goldbach's conjecture and Riemann's hypothesis can be cracked at the same time.

"It's definitely a great cause that shakes the past and the present. Shen Qi said to Ou Ye, "This work is entrusted to you, this is the historical mission of number theory researchers. ”

"It's so hard. Ou Ye removed the rubber band from his wrist and skillfully tied the ponytail.

"Rise to the top. Shen Qi patted his left shoulder with his right hand.

Ou Ye obediently tilted his head and leaned on Shen Qi's shoulder: "I want to accomplish this great cause with you." ”

That's when the movie begins.

Oh yes, it's a movie theater, one of the top three places that lovers frequent.

The heroine on the big screen is very brave, she is armed with a submachine gun, suddenly and frantically strafing, and destroys an amazing number of zombies without losing blood.

The only trouble is the zombie boss, which cannot be destroyed by conventional weapons.

The zombie boss showed his might, digging out a heart with one claw and biting off a head in one bite.

The teammates of the goddess of war heroine were all hung up, and there were no corpses to die.

"Hahaha. Shen Qi laughed, he hugged Ou Ye and untied the rubber band of Ou Ye's ponytail.

Ouye's ponytail was scattered, and his black, straight, long hair was released.

Ou Ye's hair rubbed against Shen Qi's cheeks, a little itchy, but her hair smelled good.

The fragrance of hair, body fragrance and the faint smell of Chinese medicine are mixed together, which is the unique smell of Ou Ye, which can only be smelled and enjoyed within close proximity.

There are lovers embracing each other, and horror films also see the tonality of romance films.

"You're not afraid of my long hair covering my face?" Ou Ye asked softly with his lips against Shen Qi's earlobe.

"What are your own women afraid of, you are not a ghost. Shen Qi said, and added: "I'm not afraid of ghosts, I like female ghosts." ”

"Nasty!" Ou Ye opened his mouth to bite Shen Qi's earlobe, neither light nor heavy. The strength of the lower mouth was light, and he didn't feel it. The strength is heavy, and I am afraid of biting him.

In the 152-day countdown to going abroad, Shen Qi and Ou Ye stayed in the library all day, learning their own and feeding each other when they were tired of studying.

The next few days, too.

Ou Ye, who was back in a state of study, made Zhou Yu'an feel great pressure.

It's the second semester of my sophomore year, and I'm almost halfway through my undergraduate years, and I can't catch up if I don't work hard to catch up.

Zhou Yu'an, who slept only 5 hours a day, frantically studied integrable systems and differential geometry, setting himself a main direction of attack to fight against Ouye, who specialized in number theory.

There are 145 days to go abroad, and today is the weekend.

Shen Qi fulfilled his promise and took Ou Ye to Beidaihe for a vacation. Traveling together is a compulsory course between lovers, as long as the heart is connected and love is with each other, it is the same wherever you travel.

Ou Ye never mentioned the Swiss free travel anymore, she picked up her little fist and pounded Shen Qi's chest: "Beidaihe, Beidaihe, Beidaihe! I have been here more than five times with my parents." ”

"This is my first trip to Beidaihe, and it's beautiful. Shen Qi sat on the beach, staring up at the night sky.

There are a few tourists on the beach at night, and Shen Qi and Ou Ye are one of the couples.

"I used to call people Xiao Tiantian, but now I call them Mrs. Sister-in-law, hehe, man. Ou Ye looked down and muttered, his fingers drawing circles on the sand.

"This analogy is not appropriate, you will always be my Zixia, unique. Shen Qi continued to observe the sky at night, tonight it was cloudy, windy, and the moon appeared and disappeared.

Suddenly, Shen Qi grabbed a handful of fine sand and threw it into the air, staring at the air very intently.

The sand fluttered in the wind and was blown away.

Shen Qi focuses on the trajectory and velocity of the sand in the air.

During the first atomic bomb detonation test, Dr. Fermi threw a handful of shredded paper into the air, and he accurately calculated the yield of the atomic bomb based on the trajectory of the shredded paper in the shock wave through visual observation and mental arithmetic.

Tonight's Beidaihe Beach, cloudy and windy weather, Shen Qi is doing something similar to Fermi, he is calculating the wind speed and direction.

Ou Ye was still drawing circles, Shen Qi smoothed out the circles drawn by Ou Ye on the beach, and wrote a simple formula in the same position: y(x)+δy(x)

"There is no mathematical significance in drawing circles repeatedly, Ou Ye, can you draw a mathematical curve of y(x)+δy(x)?" asked Shen Qi.

"Super easy. "Ouye immediately drew a crescent moon on the beach, which was a Lagrange variational curve.

At this moment, the wind blew away, and the moon appeared, a new moon, exactly like the curve of the crescent moon painted by Ouye.

Shen Qi's calculations were quite accurate, and the time error of the moon's appearance was less than 1 second.

The beautiful scenery of a good day, the beauty of the heavens, the beauty can not be disappointed.

Shen Qi hugged Ou Ye and pointed to the night sky: "Look, how amazing, you just finished drawing the Lagrange crescent curve on the beach, and a real crescent moon appeared in the night sky, I believe, this is the power of love." ”

The waves crash on the beach, the bright moonlight shines, and the real moonlight shines on the y(x)+δy(x) on the beach, and the crescent moon curve corresponding to y(x)+δy(x).

This situation suddenly became romantic, and the IQ of a woman in love decreased, and Ou Ye's little face blushed.

"The moon testifies, Ouye, that I will always love you and take care of you. Shen Qi's forehead was against Ou Ye's forehead, and the tip of his nose touched the tip of his nose: "If I break my promise, I will never be able to draw the correct mathematical curve." ”

"Don't lie to me. Ou Ye's face was red to the base of his neck, and his eyes were misty.

Under the moonlight, Shen Qi kissed Ou Ye.

The kiss was long and lasted for a few minutes.

At the end of the kiss between lovers, the moon in the night sky hid into the clouds.

"You...... It was deliberate, and the time was calculated. Ou Ye Jiao gasped, and the first kiss made her body burn like a fire.

Ou Ye liked this feeling, and his heart felt like it was about to jump out. Intentionally, intentionally, intentionally or unintentionally, it doesn't matter.