Lin Zhaoxi remembered that when she was not good at mathematics in high school, she was very afraid of encountering function problems.
At that time, Lao Lin was still in a coma in a car accident, and she dozed off every day in class. I feel that the so-called domain a or the corresponding law f are too abstract and difficult to understand. Sometimes she looked at the question, but she didn't even know what the question was asking.
She feels very much now.
What she has experienced all the time is like a huge function problem. Lao Lin's car accident may be the "f(2)=" she asked for, but she doesn't know what the analytical formula of f(x) is.
And now, Pei Zhi also seems to be the key variable in this function problem.
She comes from reality and is very clear about the behavior of functions and the geometric images it draws. Rather, she knows what everyone is going through right now at a certain point in time.
All she wanted to do was to change that pattern.
But almost at the moment when Pei Zhi walked into the iron gate, she suddenly realized that she couldn't solve "this problem", and she couldn't change anything.
This idea is very philosophical, and it involves the real existence of the two worlds. Lin Zhaoxi realized this, put away her rushing thoughts, and looked forward.
The ticket hall of Yongchuan Railway Station.
Lao Lin took the ticket from the conductor.
On the face of the ticket there is—
k796
"17:42" and "Yongchuan→Anning", she looked up at the huge clock hanging on the wall, and they would start their return journey in about half an hour.
If he can get home smoothly, does it mean that the specific time and place of Lao Lin's car accident have been changed
The atmosphere at the train station was lively, Lin Zhaoxi bought two boxes of braised beef noodles.
She and Lao Lin stood in the standing rest and dining area, tore apart the seasoning, poured hot water, forked it with a fork, and waited nervously for the noodles to be served.
The clock passed by every minute and every second, and she looked at the clock from time to time.
Passengers poured into the waiting hall and formed a long queue, the d198 ticket check prompt turned green, and she lifted the instant noodle cover.
Two-thirds of the noodles were eaten, and the passengers were almost gone, so d198 stopped checking tickets.
On the display screen at the ticket gate, k796 jumped to one place.
Lin Zhaoxi began to snort and drink the noodle soup, and Lao Lin came back from the toilet, took a few mouthfuls, and then put down his fork.
"Are you full?" Lin Zhaoxi turned her head and was shocked to see half of the instant noodles left in his bowl.
"I'm afraid you won't have enough to eat, so Dad wants to save a bite for you." Lao Lin said lovingly.
"Did you secretly buy roast chicken?" Lin Zhaoxi looked around sharply, and sure enough, Lao Lin was holding a bag wrapped in oil paper.
Lin Zhaoxi hurriedly reached out to grab it, and Lao Lin lifted the bag.
Just then, the phone rang.
At first there was a buzzing vibration, and then Lao Lin's usual piano bell sounded. Lin Zhaoxi tiptoed to snatch the oil paper bag and stopped suddenly.
The air was sucked out instantly, and there was no sound in the surroundings.
Lao Lin took out his mobile phone, Lin Zhaoxi watched him get on the phone, and heard him pause, and then said—
"Professor Zeng, hello."
It was as if a stone had been smashed into the river, causing ripples, and the noise suddenly poured in.
"Passengers on train k796, please pay attention, the train is about to start ticket checking."
The loud and surging sound of the broadcast sounded right above their heads, almost overwhelming Lao Lin's voice on the phone.
Lin Zhaoxi barely discerned the general content of the whole phone call from Lao Lin's lips.
"Yes, I've come to Yongchuan, and I'm at the train station now."
"It's almost there, and it's still being revised."
Finally, after a three-second pause for thinking, Lao Lin shifted his gaze to her and said—"Okay, then I'll go over now."
Lin Zhaoxi grabbed the oil paper bag in a ridiculous posture and looked at Lao Lin nervously.
"Why, eat yours, not steal you." After answering the phone, Lao Lin looked a little relaxed.
"Who is Professor Zeng, Dad?" she asked tentatively.
"The old man who gave you a speech at the elementary school Mathematics Olympiad Summer Camp." Lao Lin walked out of the waiting room with a look of "you know what you are asking".
Lin Zhaoxi's heart sank again, and she took two quick steps to keep up, only to hear voices rumbling in her ears: "Where are you going, the ticket check is about to begin."
"Sanwei University, they want me to go there, and we will take a later train back."
She grabbed Lao Lin, and somehow blurted out: "Don't go, let's go home quickly?"
"What's the matter, are you suddenly falling in love with your family?" Lao Lin still looked relaxed, but stopped, listening to her reasons seriously.
How should I say it
Said "I'm afraid that you will encounter accidents in Yongchuan", or "Let's go home and stay well this week and don't go out"
But Professor Zeng's sudden phone call was obviously related to Lao Lin's thesis. How could she tell Lao Lin not to go
The ticket check prompt turns green, and the gate starts to release people.
Lin Zhaoxi looked back at the turbulent flow of people preparing to leave Yongchuan in the waiting room, and knew that the huge function problem she encountered had a limited value range for solving the problem.
She looked at Lao Lin and felt a powerful force pushing them into the established track, but in the end she could only say: "Let's go."
—
Sanmi University, the old campus.
There are a large area of dense evergreen street trees on the campus, which is gloomy and gloomy in winter nights.
Lin Zhaoxi and Lao Lin stood outside the building of the Department of Mathematics and met Professor Zeng.
In the night, the old man's hair was gray and he looked very energetic.
"Your daughter is already this old?" Professor Zeng took out a steamed bun from his coat pocket and asked, "Are you hungry, can I have a steamed bun?"
Along the way, the strings in Lin Zhaoxi's mind were tense, and she felt cold in her bones, so she took the steamed buns and said bluntly, "Thank you."
After a while, Professor Zeng looked back at the steamed bun and said to Lao Lin, "It's really your daughter."
"Okay." Lao Lin was straightforward, took the steamed bun back from her hand, and broke it in half.
"Put away your supper." He handed back half of the steamed bun to Professor Zeng, and took a bite of the other half.
They walked into the building and looked familiar, but Lao Lin was so casual with most people.
The conversation between Lao Lin and Professor Zeng was neither salty nor dull, and Lin Zhaoxi followed behind them.
When she was approaching the door of the office, the people waiting inside made her stop. Inside was a professor from the School of Mathematics of Sanwei University. There were two faces she had seen in real life when she was in college.
Only then did Lin Zhaoxi realize that Lao Lin was invited to participate in the peer review before the paper was published.
For unknown reasons, Lao Lin sent the paper to Professor Zeng for reading, and Professor Zeng invited Lao Lin to explain it in person.
In the winter night, her heart beat heavily, nervous and excited.
In this case, of course she couldn't follow in.
"I'll wait for you outside." She said to Lao Lin.
"Find a warm place."
"kindness."
—
Office of the Dean of Mathematics.
The yellowed shutters were drawn, Lin Zhaoxi turned around and returned to the office door.
Through the gaps in the broken leaves of the shutters, she could see that there were only two chandeliers lit in the office, and a stack of printed papers was placed on the table, but no one looked through them.
The room in the office was filled with smoke, and there was a whole blackboard wall, and Lao Lin stood in front of the blackboard.
In the winter night, there is a cold wind blowing through the leaves, making a very thin rustling sound.
Lin Zhaoxi gripped the strap of her schoolbag tightly.
On the seat, Professor Zeng raised his head.
He looked at Lao Lin with a serious and serious expression, as if saying—"Let's get started."
—
Lin Zhaoxi put her schoolbag on the ground, leaning against the wall of the office.
It was cold at night, and the hallway was like an ice cellar.
When she sat down, she shivered, flicked through her schoolbag, and kept thinking about what would happen next, not yet free from the panic of being forced by fate to the established track.
From her schoolbag, she found some manuscript paper with Pei Zhi and Lao Lin's handwriting, a picture theory book she carried with her, and her pencil case.
The winter night was silent, and when she raised her head, she could see a bright moon hanging over the city, bright and clear.
Sitting down with her schoolbag on her buttocks, she opened the book.
—
The only sound in the office is the sound of flipping through papers and smoking, which is very light and slow.
The smoke is bigger.
Lin Zhaoxi spent much more time than usual on a practice question after finishing the book. Her hands were stiff with cold, but her mood seemed to calm down a little.
She looked into the office again.
Most of the chalk writing appeared on the blackboard, but the atmosphere was stagnant. It seemed that someone was asking a question. The question was very tricky and sharp, and everyone looked at the questioner.
Lin Zhaoxi looked at Lao Lin.
Her father is no longer young, with white chalk dust on his fingers, and even his cuffs are gray.
His eyes are calm, but full of firm spirit.
After listening to the question, he didn't speak, and replaced by chalk words that appeared on the blackboard.
One line, two three, three lines...
Everyone frowned for a while, and then showed some relaxed expressions, as if they realized that this was a perfect solution.
Professor Zeng took a drag on his cigarette, narrowed his eyes, and seemed to say—"Continue."
—
Lin Zhaoxi sat down again, and turned the next page of the book.
The hour hand made a circle, and then another circle.
The ashtray on the table was full of cigarette butts, and a new one was pressed out.
The blackboard has been wiped several times, and any unevenness is about to be filled.
Lin Zhaoxi was still looking at the topic on her lap—
(2): Write out the adjacency matrix of g.
She thought about it and continued writing.
—
Someone once said that most of the most important achievements of mathematicians were made before they were 40 years old.
Mathematicians after 40 are useless.
Today's Lao Lin happened to be stuck at this threshold.
In the office, one problem after another was thrown and then resolved.
Many mathematicians walk alone in the dark all their lives, how many of them are lucky enough to experience the moment when the light pierces the darkness
The landscape lights on the campus are completely extinguished, and the cedar trees are swaying in the cold wind.
Lin Zhaoxi put down her pen, rubbed her palms together, and took a deep breath.
At this moment, there was a light "click" sound in the space.
Lin Zhaoxi turned her head abruptly, and the lights seeped into the corridor through the crack of the door like water.
The door is open.