Chapter 36
Chapter 36
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Translator: Ace
Chapter: 36
Chapter Title: Unbreakable Logic
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Kim Ji-yoon didn't wait for the students' murmurs to die down.
She pulled a piece of chalk from the holder on the desk and wrote four large words boldly in the center of the board.
"This semester, we'll proceed strictly in this order. I'm not interested in pretty solutions. A proof can crumble even if it's short, or be a pointless detour even if it's long. The key is logic that never breaks!"
Ji-yoon wrote 'Logic' in huge letters.
"When you think of math, numbers probably come to mind first, but the most important thing in mathematics is a proof built on perfect logic. The other three steps I wrote are the process for constructing that flawless logic. Shall we test it out real quick?"
Professor Kim Ji-yoon clicked her mouse, and a problem appeared on the board.
A student in the middle raised his hand confidently.
"Uh... Kim Jung-hwan? Go ahead."
"The blue-eyed person immediately realizes their eye color and leaves the village."
Since everyone knows everyone else's eye colors, if there are no blue-eyed people among those they know, then it must be themselves.
Most nodded, thinking along similar lines. But Ji-yoon shook her head.
"Wrong. Can anyone refute that?"
Seo-ha raised his hand.
"There's a flaw in that answer."
"If there's only one blue-eyed person, they hear the traveler and think, 'Ah, that's me!' and leave right away. But if there are two or more, it's different. They look at each other and think, 'That person will leave.' They wait.
"On the first night, no one leaves. So on the second day, they realize they were thinking the same thing and leave. With three, it's the third night; four, the fourth... and so on."
Honey practically dripped from Ji-yoon's eyes as she looked at Seo-ha.
"Perfect. For logic not to break, you must consider every possible case without omission. The key is no holes in the logic. In math, a proof fills those gaps.
"If it wavers even slightly, it's not complete logic."
Tension rippled through the students.
"Of course, the opposite can happen too. Overfilling those holes doesn't make a good proof either."
Ji-yoon clicked her mouse, and a new passage appeared.
"This is an actual report from a past theft case. Let's trim out the parts unnecessary for the proof."
Seo-ha was thrilled.
Professor Kim's class was so enjoyable he felt like dancing.
Seo-ha's lifelong teacher had always been books.
From the moment he learned to read at age two, there hadn't been a single day without a book in his hands.
Under the lamplight, he was always alone.
Seo-ha posed questions to himself while reading and found answers on his own. Questions without answers went on his 'Unsolved' list, to be revisited and resolved later no matter what.
He always imposed a process on himself while reading. When encountering a new concept, he first wrote down the definition. Then he rigorously self-verified if it was right or wrong.
When Professor Kim Ji-yoon wrote 'Definition - Theorem - Proof - Critique,' Seo-ha's heart raced. It was the exact process he'd followed instinctively since childhood, as naturally as breathing.
So, Seo-ha's strength in logic was inevitable.
The students read the report with serious eyes.
Was it because the writing style differed from what they usually read? They pondered deeply but struggled to grasp what to keep and what to cut.
"Isn't the power outage important? That's why the CCTV stopped..."
"The woman using her phone is a clue, so we can't delete that."
"The shop owner's opening time is an alibi, so it's necessary."
Whispers rose here and there.
Soo-jung furrowed her brow, headache brewing as she mulled over each sentence.
The densely packed incident summary was suffocating, tangled with miscellaneous facts: time of the crime, shop owner's opening time, eyewitness accounts from nearby cafe staff, CCTV outage due to power failure, safe description, even a former employee...
But Seo-ha didn't hesitate for a second.
He quickly scanned the text with his eyes and shot up his hand.
"Professor, most of the clues listed in this report are unrelated to the conclusion."
Seo-ha stepped forward and began crossing out sentences one by one.
The students gasped softly at his bold moves. Facts they'd thought might be clues vanished. In the end, only three lines remained.
"Excellent!"
Ji-yoon stood up with a smile.
"See how the core becomes clear once you remove the unnecessary facts? The culprit was that employee.
"Proofs in math are the same. You don't need to use every condition given in the problem. In fact, non-essential conditions cloud your vision, so eliminate them quickly. The goal is airtight logic!"
"Now, everyone, give Yoo Seo-ha a round of applause!"
Clap clap clap!
Seo-ha's face flushed red.
Then Ji-yoon approached and whispered in his ear.
"Seo-ha, I told you to drop by my lab anytime. Why haven't you? I had to come all the way here to see you."
"Eek!"
Seo-ha flinched, his body hair standing on end.
The logic games continued after that.
One student presented an argument; others tried to dismantle it.
And Seo-ha was the devil of that game.
Every student's logic shattered against him. No one could crack his.
"Wow... I've never seen anyone like you."
Soo-jung stuck out her tongue in disbelief.
Once the basics of logic were laid, Ji-yoon had the students apply it to math.
Seo-ha's mind spun.
The problem on the board looked like a standard function proof.
But approaching it her way revealed a whole new side.
For Seo-ha, learning had always been solitary.
Of course, he found even that process plenty enjoyable.
But Ji-yoon was the first true teacher he'd ever met who could guide him.
Seo-ha was moved by this direct instruction, a first in his life.
Ji-yoon smiled warmly, watching him.
After starting elementary school, Seo-eun grew into a spirited girl. Bathed in her family's love, she had no trace of timidity in her actions.
"Teacher! I know!"
Whenever the teacher asked a question, Seo-eun's hand shot up first.
One Saturday afternoon,
Seo-eun lay sprawled on the floor mat, legs kicking alternately like she was dancing, lost in some fun game.
Mi-young peeked over and saw her drawing with crayons.
She had Yoo Seo-ha's old sketchbook open, scribbling wobbly words like 'Triangle' and 'Square' as she immersed herself in study—or so she thought it was shape play.
"The sum of interior angles in a square is 360 degrees. Half of that makes a triangle, so 180. Then a pentagon is three triangles, so 540 degrees?"
Mi-young thought, 'She's weirdly picked up that habit from her brother.'
"Mom! I'm home!"
A familiar voice from the front door.
Her now much larger son shrugged off his big bag and entered. Seo-eun, sprawled on the mat, jumped in surprise, eyes wide.
"Oppa!"
Seo-eun sprang up, ran over, and clung to Seo-ha's waist with arms wide.
Seo-ha scooped her up effortlessly with both hands. Seo-eun giggled wildly, flailing her limbs in the air.
"Seo-eun, playing with shapes?"
"Yeah! A hexagon is four triangles!"
Seo-ha laughed and hugged his sister tight.
"Come eat."
Mi-young took his bag and pried Seo-eun off.
Cheol-ho, who had been watching TV in the room, came out to greet Seo-ha warmly.
'Ah, home!'
Coming home from the tense school felt like a breath of fresh air.
Seo-ha wolfed down two bowls of his mother's soybean paste stew and took Seo-eun for a neighborhood stroll.
As evening fell, he sat at his familiar desk.
"Attempt 178."
Mathematicians obsessing over tough problems is as natural as bees seeking flowers.
But anyone who cared for Seo-ha would surely stop him if they saw this. Clinging to a hard problem is far too dangerous.
Paul Wolfskehl devoted his life to proving Fermat's Last Theorem but failed. He died without letting go, willing his entire estate to whoever solved it.
Louis de Branges is infamous as a scholar haunted by the Riemann Hypothesis. He obsessed for over 30 years, failed, and faded from academia amid pressure and despair.
The Four Color Theorem had stumped and defeated countless mathematicians before.
It wasn't even elegant anymore, just a solved problem.
There was no reason for a promising boy like him to fixate on it.
Scratch scratch.
But giving up wasn't an option for Seo-ha from the start. This was the first 'unsolved' problem he'd ever faced in his life.
He'd spent so long on it that he knew every dead end and blockage.
So instinctively, he avoided every wall.
The deeper the research, the taller the obstacles.
That was Seo-ha's dilemma.
But on the 178th try, something felt different. His sharp mathematical intuition screamed it wasn't.
'Huh? Do I really have to avoid this path? Maybe I can handle it later with another approach.'
Sudden insight flooded him.
He recalled Ji-yoon's class.
'You don't need to use every given condition. Eliminate non-essential ones quickly.'
He already knew it, but her words shattered the inertia of avoidance, revealing another path.
Scratch scratch.
Seo-ha's pencil ventured down the new road.
His hand flew nonstop over equations filling the page. In the heavy, still air of the room, he pressed on silently.
Scratch scratch.
The answer wasn't visible yet.
But it was worlds apart from before. Back then, it was wandering endless plains. Now, he was trekking toward an oasis somewhere in the desert.
The massive wall that had blocked him for years finally began to crack before his eyes.