Ding-dong-ding—
Class had ended.
Seoha packed his textbooks and writing utensils into his bag. His head was throbbing and he was running a fever; his condition was not good.
‘I need to resolve this quickly…’
The problem he had been grappling with since last night swirled in his head. It was a variation of Goldbach’s conjecture. A new approach had occurred to him, but he had yet to complete it.
Seoha calculated time in his head.
One day is 1,440 minutes. Time used so far: 521 minutes.
Subtract sleeping time—the family had a set lights-out time—of 480 minutes, and the net available time was 289 minutes.
‘This is enough. It’s almost five hours.’
Seoha left the classroom with quick steps.
The important thing was not to waste time.
Seoha exited the school main gate at exactly 3:19:58. To the crosswalk: 1 minute 12 seconds. Arrival at 3:21:08.
The signal was scheduled to change at 3:21:10.
Seoha had known this pattern for three years. He had naturally grasped it by commuting to and from school at the same time every day.
The traffic light cycle was 120 seconds. Green: 40. Red: 80.
During lunch time, there was special signal adjustment prioritizing pedestrians.
There had been a day when, to figure out this condition, he spent the entire day off measuring time and watching the signals. Thanks to that, knowing the perfect timing had been worth the effort.
If he took one step now, the signal would change right away.
It should have been certain, but…
The signal did not change.
‘What’s going on? Was a new rule added? Or is the traffic light broken?’
But everyone waiting for the signal except him had calm faces.
‘Where did I go wrong?’
His head turned blank. The pattern that had been perfect for two years had broken.
Seoha’s breathing grew rough. He began to sweat. Seoha started checking the time while looking at his watch.
The signal changed after 11 seconds.
How many cycles had passed from 8 a.m. until now?
From 8:00 to 15:21:21 is 7 hours 21 minutes 21 seconds.
Converted to seconds: 26,481 seconds.
Divide?
Seoha’s steps slowed.
220.675
A decimal.
‘0.675.’
27/40. Coprime. It could not be reduced further.
‘Strange? Such a complicated fraction shouldn’t come out of this.’
Something was wrong. This shouldn’t happen.
While feeling confusion, his body swayed.
“Huh?”
Seoha’s body stopped forcibly.
Someone had grabbed his bag from behind and pulled him.
“Hooooonk—”
Instantly, a truck blared its horn loudly and passed before his eyes.
It had been dangerous. He had really almost died.
Attempting to convey his gratitude, he turned around, but…
“Seoha. Are you okay?”
His mother’s face, full of worry. Whether she had run, sweat beaded on her forehead. Seoeun also had an uneasy expression as if she were about to cry.
“Mom?”
His burning head cooled down coldly.
‘What on earth was I doing?’
“Why are you here…?”
Seoha blankly looked around.
The place where he had been standing was in front of the school crosswalk. But what he saw before his eyes was the main road near his house. He had no memory at all of how he had gotten here.
“I was coming home from shopping with Seoeun! I spotted you, but no matter how much I called, you didn’t answer….”
In fact, that wasn’t all.
Even from afar, Miyeong had clearly seen her son’s face deathly pale. Worried he might be sick somewhere, she had held him in her arms and run with all her might.
“Oppa, carry me!”
Before she knew it, Seoeun, who had gotten down from her mother’s arms, stretched both arms toward Seoha. Seoha lightly lifted his younger sister.
A familiar weight and warm scent.
Seoeun wrapped both arms around her brother’s neck.
Seoha’s heart began to calm down little by little. The numbers swirling in his head disappeared, and the calculations that had incessantly failed to stop no longer tormented him.
“Oppa, are you okay? Your face is pale.”
Seoeun touched Seoha’s cheek with her small hand.
“Of course I’m okay. I’m just a little tired today.”
Not wanting to worry his family, Seoha forced a smile and answered.
“Let’s hurry home and rest. Mom will make something delicious.”
On the way home, a cool wind blew.
Trickle, trickle, trickle.
The sound of stream water flowing in a small creek.
Nearby, various wildflowers shyly poked their heads out.
“Oppa, what are the names of those flowers?”
“Daisies and hydrangeas.”
Five years old, an age where everything in the world is curious.
Seoeun poured out questions without rest, but there was no stoppage in the answers of Seoha, who had memorized the entire encyclopedia.
‘Ah! It’s peaceful. Exactly the usual appearance of our family.’
Only then did he feel his heart becoming free.
* * *
Saturday, 10 a.m.
Seoha entrusted his body to bus 705 and headed toward downtown Daejeon.
Gazing at the scenery passing by outside the window, he recalled what had happened to him a few days ago.
The blank in memory, the moment when he had almost jumped in front of the truck at the crosswalk.
And the collapse of the traffic light pattern that had triggered all of it.
‘I really could have died.’
Seoha had no intention of underestimating what had happened then. The fact that there might be something seriously wrong with him was unsettling. More precisely, he didn’t want to see his family saddened because of it.
‘Let’s find the cause.’
Analyzing the phenomenon from given conditions, establishing a hypothesis, and proving it.
Seoha decided to approach his own problem with the logical thinking of a mathematician.
The bus arrived at the city center and spilled out people.
As Seoha had investigated in advance, he immediately made his way to the large bookstore boasting the largest scale in the country.
Upon entering the bookstore, numerous people were sitting freely reading books.
Passing the essay, novel, and workbook corners, Seoha’s feet faltered.
Countless medical books were densely displayed.
Modern Psychiatry, Introduction to Clinical Psychology, Neuropsychiatry, Adolescent Mental Health…
Slowly scanning the titles, he finally found the book containing the information he sought.
「Understanding and Treating Obsessive-Compulsive Disorder」
Shhk, shhk.
Obsession, Compulsion—various symptoms were listed, but there was no explanation that exactly fit his case.
Shhk, shhk.
The hand that had been quickly turning pages stopped.
Seoha’s hand trembled.
Arithmomania and mathematical thinking disorder.
—Arithmomania is characterized by an obsessive fixation on numbers and calculations. Patients constantly calculate in their heads or assign meaning to specific numbers and become excessively fixated on mathematical patterns.
Main symptoms.
—Obsessive calculation of time, distance, quantity, etc.
—Excessive fixation on specific numbers or patterns.
—Uncontrollable urge to solve math problems.
—Extreme anxiety when calculations are wrong.
—Significant decline in daily life functioning.
Each time he read an item, he imagined himself fitting into it.
Goldbach’s conjecture that had not left his head all night long.
Was it normal to research traffic light patterns for several years? Was it normal to panic when the pattern broke?
Was dividing the day into minutes and seconds an ordinary thing?
‘Since when did these symptoms appear?’
Seoha sat in a quiet corner chair and looked for more materials.
“This man was in a bad way.”
Kurt Gödel.
The greatest logician of the twentieth century.
He had revolutionized the mathematics world with the incompleteness theorems, but in his later years he suffered from severe obsessive-compulsive disorder and paranoia. Believing his food was exposed to poison, he ate only food prepared by his wife, and during the six months his wife was hospitalized, he ate nothing and eventually starved to death.
“Tsk, tsk.”
‘He’s much worse than me, right? No matter what, how could a human….’
But reading the next paragraph, Seoha’s relief disappeared.
‘Gödel’s early symptoms were minor. In his twenties, his symptoms were dismissed as merely a fixation on mathematical accuracy. But untreated and neglected obsessive-compulsive disorder….’
‘Ah… Damn it.’
‘No, I’m different. Because I’ve already recognized the problem.’
Seoha examined other mathematicians’ cases.
Georg Cantor.
Founder of set theory. In 1904, when his theory was refuted at a conference, his obsessive-compulsive disorder developed into bipolar disorder. He was eventually confined to a mental hospital and ended his life.
Isaac Newton.
Suffered from bipolar disorder his entire life.
Washed his hands dozens of times a day and even had hallucinations.
Leonhard Euler.
The teacher of all mathematicians. In 1771, blindness after cataract surgery.
However, he could not stop calculating obsessively. Immersed in calculating Uranus’s orbit until just before death.
The eulogy left by Count Condorcet, his closest friend, at the funeral was: “Death has finally stopped Euler’s calculations.”
Here and there, patients everywhere.
Numerous mathematicians had disorders, to greater or lesser extents.
Seoha moved to another section and studied the diagnosis and treatment methods for this in detail.
* * *
“Hahaha!”
Coming to the bookstore had been the right answer.
Treatment was easier than he thought.
Over 90% of patients were cured; the earlier the diagnosis, the better.
‘In Gödel or Cantor’s times, the concept that such symptoms were an illness didn’t even exist.’
He was different from them.
Hopeful numbers made his heart light.
‘Long live modern medicine!’
On the way home, Seoha intentionally did not measure time. On a normal day he would have known the exact arrival time, but today it had nothing to do with him.
‘I can just wait. What’s the big deal.’
He felt like a wise man.
When the signal changed, Seoha naturally crossed the road. It was neither difficult nor tormenting.
‘I can control it sufficiently.’
Many great mathematicians had been imprisoned in the jail of numbers for their entire lives and could never escape, but Seoha vowed that he would never become like that.
He arrived in front of the house but did not look at his watch. He simply opened the front door.
“Mom!”
What was important about how long it took?
Normally he would have habitually checked the time he got off the bus and the time he arrived home to calculate his walking speed, but such things were no longer important to him.
“I’m home!”
“Welcome! You should eat!”
It was dinner time.
Seoha quickly washed his hands and feet and helped set the table.
“Our Seoha always places his spoons so neatly, doesn’t he?”
“Yes, yes! He was like that since he was little.”
Feeling good at his parents’ praise.
Seoha stared blankly at the spoons he had placed. The tips of the spoons aligned exactly with the edges of the square dining table.
A perfect right angle.
An uneasy feeling crept over him.
“Take the sausages.”
Receiving the plate, Seoha unconsciously removed one with the tongs.
“Why are you doing that? Don’t you like sausages?”
At Cheolho’s question, Seoha was at a loss for words.
“Ah, honey! Seoha usually puts only seven on his plate. Maybe because Seoeun doesn’t eat well.”
No. That wasn’t it.
He simply disliked the number eight.
Was that all?
Why had he insisted on seven?
7 is a Mersenne prime that can be expressed as 2^p−1. At the same time, it is also a safe prime where (7−1)/2=3 becomes a prime number. The regular heptagon is the first regular polygon that cannot be constructed using only compass and straightedge.
Seoha disliked easily expressible numbers like the perfect number 6 (1+2+3=6) or the perfect cube 8 (2³=8).
7 is simply 7 and cannot be cleanly expressed by any other combination.
“Aaaaaah!”
Seoha despaired.
“What’s wrong?”
Miyeong asked, seeing her son clutching his head.
“Ah… it’s nothing. I just remembered I forgot my homework.”
Seoha quickly ate his meal and went to his room.
Closing the door and leaning his back against it, he let out a deep sigh.
‘Completely ruined. Different, my ass….’
Then a strange thought suddenly flashed through his head.
Seoha unconsciously opened the closet door.
Checkered clothes filling the closet.
‘No… it can’t be.’
Hurriedly, he took out a ruler from the drawer and held it against the checkered pattern.
1 : 1.618
It was the golden ratio.
All the clothes he had liked until now were exactly the same.
The obsession with numbers that had formed since early childhood was rooted far deeper than Seoha had thought.
“Aaaack! They said the cure rate was ninety percent! They said it was easy!”
Seoha covered himself with a blanket and screamed.
‘Could I be the remaining ten percent?’
He had only looked at the positive side because he was feeling good, but this was a figure that mathematically could never be ignored.