Reconstructing the Original
“Y-you didn't tell him?”
“Well, you said back then that you just wanted to have a casual chat...”
“Ah, I completely forgot...”
Park Ye-ji let out a quiet sigh at her advising professor's words.
No wonder. She had thought it was strange being told to go to the music school's recital hall...
“So, what did the kid say?”
“He said it's fine. He's actually glad there will be plenty of people to ask...”
“Really? Phew, that's a relief. But does he have any presentation experience?”
“Probably not.”
“Oh dear. He's going to be incredibly nervous.”
One of Ye-ji's eyebrows twitched.
That question-monster, Cheol-jun, getting nervous?
She couldn't quite picture it.
Still, with so many adults watching, maybe he might be a little nervous?
He is still a kid, after all.
“Ye-ji.”
“Yes?”
“Let's go over this one more time.”
Her advising professor tapped the printed sheet music.
“Are you absolutely sure he did this all on his own?”
“Yes. As far as I know.”
“And you were the one who provided the MCM materials?”
“Yes.”
“You didn't touch a single thing on there, right?”
“I only answered his occasional questions as they came up. He showed me that sheet music for the first time that day too.”
“...Are you absolutely sure he's that smart?”
“Yes. Incredibly so!”
“Please... I really hope so...”
“......”
“Whew... This has gotten way out of hand, hasn't it?”
Ye-ji pouted slightly, making sure he didn't see.
And whose fault is that?
If he was so anxious, he should have checked it himself first.
Cheol-jun had shown her the sheet music and said he wanted to ask someone who knew more about it, so she had printed it out and shown it to her advising professor.
She thought it would help since he knew far more than she did.
To be honest, she couldn't fully comprehend Cheol-jun's sheet music herself.
She had only intended to set up a meeting between the two, but things had spiraled out of control before she knew it.
After she left that day, her advising professor had gotten incredibly excited, taken the sheet music, and run to the distinguished professor. Then, the distinguished professor had gotten just as excited and run to the dean.
Ye-ji felt a bit bitter that she hadn't been kept in the loop at all during this process, though she wasn't surprised.
It just showed how little a graduate student slave's opinion mattered.
Anyway, because of that, she had only been given the time and place of the meeting, so she had passed it along without any other explanation.
Even though it was a bit strange, she had genuinely believed he was only meeting her advising professor.
'Seriously, that man...'
True to his reputation as the icon of poor communication, his handling of things was a total mess.
Still, at least he wasn't blaming her.
And fortunately, Cheol-jun had taken it well.
“U-um, make sure to take good care of student Cheol-jun... If this goes wrong, you and I... No, what fault do you have? Anyway, I'll be dead on the spot. You know the dean's personality, right? He even dragged the chair of the piano department here, so if... *Sigh*...”
Hearing him talk like that made her feel a bit sorry for him.
His hands were actually trembling.
He might be terrible at communicating, but compared to other math professors, he did have a somewhat human side.
“Excuse me, Professor.”
“...Huh?”
“You don't have to worry at all.”
“...What?”
“Our Cheol-jun is a genuine genius.”
She had originally planned to keep quiet to let him squirm a bit more out of spite, but...
“The dean will probably fall out of his chair in shock.”
“R-really?”
“Now, take a deep breath.”
“Whew. Whew.”
“Trust Cheol-jun.”
“Whew. No, Ye-ji, I'll trust you.”
'Suit yourself.'
Ye-ji smiled warmly and patted her professor's back.
What a timid man.
Sitting in the front row of the recital hall with his legs crossed, Kim Seong-cheol, the Distinguished Professor of the Piano Department, stared blankly at the materials handed to him by the department chair.
“Sigh, what is all this scribbling on the sheet music... Tsk.”
“U-um, they say it's Fourier series...”
“I know that.”
“......”
Kim Seong-cheol glanced at the Dean of the College of Natural Sciences sitting quite a distance away.
Next to him, the math department chair and their distinguished professor were huddled close, whispering to each other.
Looking around, he spotted a camera mounted on a tripod.
Furthermore, someone who seemed to be from the Natural Sciences support office was walking around with a camera.
Kim Seong-cheol gestured with his chin and asked,
“What's that for?”
“Well, they say they want to keep a record because it might end up as a hypothesis rather than a full proof. They want to film the entire process so they won't face unnecessary suspicion later...”
“Tsk. They always love their absolute certainty over there.”
“......”
“I mean, it's not even Bach, just a single Mozart Minuet, and they're making such a fuss... Tsk. And they expect me to believe an elementary schooler did this alone? It's obvious they fed him all the answers. Hah, seriously... What's this? A private elementary school? Did they get some kind of bribe from them?”
“Oh, surely not.”
“They said he's not even in the gifted education center, right? Yet they blew things up to this scale? The school is a Gangnam private school too. Hanyoung Elementary... Hm? Hanyoung? So, Hanyoung... Huh? Wait, his name is...”
Kim Seong-cheol, who was looking over the information of the elementary schooler presenting today, adjusted his glasses.
'Lee Cheol-jun?'
Kids' names these days all sounded like celebrities.
While it might have been common in the past, such an old-fashioned name was extremely rare among elementary schoolers today.
Moreover, the same elementary school and the same grade?
Kim Seong-cheol's face went blank.
The department chair, observing Professor Kim's reaction, tilted his head.
“Is there a problem...?”
“Uh, what? No, it's nothing.”
“Ah, there he comes. That must be the boy.”
Kim Seong-cheol quickly turned his head.
A small frame, a private elementary school uniform.
And round eyes on an incredibly cute face.
It was definitely him.
It was the child he had seen in the KakaoTalk photo back then.
'Ha...'
Kim Seong-cheol adjusted his glasses and blinked.
A tense battle of nerves had been brewing in the music school's recital hall long before the presentation began.
The Dean of the College of Natural Sciences felt immense discomfort at the whiteboard, which was placed awkwardly far away from the angled piano for the sake of visual proportion.
So he told his department chair to place it in front of the piano. When the chair had the math teaching assistants move it, Kim Seong-cheol, the Distinguished Professor of the Piano Department, gritted his teeth and had his own department chair move the whiteboard far away from the piano again.
The sound needed to reflect off the lid and spread toward the audience, but blocking it with that eyesore of a whiteboard was absolutely unacceptable to Kim Seong-cheol.
It was something he could never tolerate.
Although the Dean of the College of Natural Sciences glared at him openly, Kim Seong-cheol avoided the stinging gaze, muttering to himself, “Coming into someone else's house and acting like they own the place.”
Anyway, the whiteboard ended up in an awkward position for the mathematically sensitive crowd, but another problem arose when the boy presenting today entered.
'I thought they said he was in the fifth grade?'
'Ah, he's quite short.'
Even when the boy stretched his arm as far as he could, he could only reach the middle of the large whiteboard.
They hurriedly brought him a chair to stand on, but the boy furrowed his brow slightly and began to drag the whiteboard himself.
It had wheels, but because it was a large double-sided board, it looked a bit heavy for him.
While the math department chair quickly signaled the teaching assistants, the homeroom teacher—who had brought the boy and was standing beside the stage—rushed up.
“Cheol-jun, what's wrong?”
“Well, it's too far from the piano.”
“Ah, should I move it over there for you?”
“Yes! If it's there, it'll be easier to ask questions while playing the piano from time to time.”
“Alright, here?”
“Yes! Thank you!”
Go Chang-ho was unaware of the subtle war of nerves that had just occurred between the math and piano departments.
So he simply placed the whiteboard right in front of the piano, exactly as Cheol-jun wanted.
In an instant, quiet chuckles escaped from the math department's side, while the chair of the piano department gasped and nervously checked the distinguished professor's reaction.
Surely, a thunderous scolding would rain down... right?
'Wait... he's holding it in?'
His face was extremely displeased.
That much was certain.
It was a face that should have exploded by now, but he was clenching his teeth, trembling as he held back.
The department chair blinked.
For that fiery distinguished professor, who had been sharpening his knives waiting for any excuse to blow up, to tolerate such an outrage...
Even the department chair himself found it hard to bear.
How dare they put such an eyesore in front of the sacred piano...
“Hello! I am Lee Cheol-jun from Grade 5, Class 5 of Hanyoung Elementary School!”
At the boy's greeting, the department chair quickly turned his attention back to the stage.
“Um, I didn't really come to give a presentation, but rather to ask a few questions.”
They had given him a microphone, but he only used it for the greeting and was now just holding it in his hand without bringing it to his mouth.
The homeroom teacher, who had just committed that massive outrage, went back up to the stage and held the microphone near the boy's mouth.
“So, what it is...”
The boy hesitated, then picked up a dry-erase marker and began scribbling on the whiteboard.
But after writing a little, he stopped.
He tilted his head.
Then he walked toward the projector screen.
He tried to bring the marker to the sheet music projected on the screen.
“Cheol-jun, not there!”
At his teacher's words, the boy flinched and blinked his round eyes.
“Ah, I can't draw on this?”
He stared at the whiteboard with a contemplative look.
“It's a hassle to draw the whole sheet music...”
The piano department chair scowled deeply.
What insolence!
Mathematical formulas weren't a hassle, but drawing a simple Mozart Minuet was?
Believing the distinguished professor would feel the same way, the department chair quickly turned to look at him.
But!
'Huh?'
He was tolerating this too?
Moreover, the piano department chair's eyes widened even further as he felt like the distinguished professor was actually wearing a faint smile.
“So, over there, did you set the progression regularity index as R and divide the total number of measures by the number of repetitions? And used that to determine the pattern regularity?”
“Yes. If you look here, it comes out to 0.75. Personally, I thought that was a bit high.”
“Ho, what did you expect it to be?”
“Around 0.4.”
“Did you design the note distribution chart yourself? As a bar graph?”
“Well, a probability distribution works too, but since this piece is simple...”
“Exactly! A geometric approach is intuitive and fast. So, according to that graph, the original piece's entropy would have been higher?”
“Yes. The note durations were too uniform. If you look at H here, it's 0.88, but in reality, I felt it should be set to around 1.4.”
“How did you calculate the unexpectedness of the average leap?”
“Since the standard deviation is 0.9, the outlier threshold is 3.55 semitones, but since a leap of 9 semitones was used, this part significantly exceeds...”
Kim Seong-cheol, the distinguished professor of the piano department, stared at the tiny, cramped handwriting with a deep scowl.
No matter how much he looked, he couldn't make heads or tails of it.
He wanted to ask questions too, but he couldn't even begin to guess what the two of them were talking about.
Honestly, he felt like his insides were burning.
To think his first meeting with Cheol-jun would happen so abruptly in such an awkward setting.
He couldn't even pretend to know what was going on, which was incredibly frustrating in its own right.
He couldn't recognize what was written on the whiteboard, nor could he understand a single word they were saying. Yet, his hovering nearby was a desperate struggle to ease his frustration even a little. But listening only made him feel more lost.
As if reading Kim Seong-cheol's mind, the department chair stepped in and began to quietly translate for him.
Since the department chair had studied some mathematics while preparing for the MCM a few times, he could roughly grasp the conversation.
“Well, the part they are discussing now is about how the melody pattern is too regular and the rhythm is too uniform. He's saying he deconstructed, calculated, and analyzed it using those formulas.”
“......”
“And finding the outliers in the melodic leaps refers to explaining the parts that far exceed the standard average leap of the notes.”
“......”
“And that last formula is for back-calculating based on the analysis so far, to find the pure Wolfgang's Minuet untouched by Leopold's hand... Uh, but even I don't quite understand that part...”
Kim Seong-cheol found the Dean of the College of Natural Sciences, who was crouching next to Cheol-jun and chatting with him, incredibly obnoxious.
He wanted to smack that balding head of his.
He had been secretly looking forward to hearing Cheol-jun play the piano, but to find out so suddenly that it was all because of mathematics made his stomach churn.
And to make matters worse, the boy was having such a warm conversation with that eyesore of a man in a language he couldn't even comprehend...
“I mean, so when is he actually going to play the piano?”
The complaint slipped out of his mouth a bit louder than intended.
'Ah...'
The math geeks, who had been listening intently to the conversation between Cheol-jun and the Dean of Natural Sciences, turned their heads simultaneously to look at Kim Seong-cheol.
Their gazes felt as if they were all sighing inwardly.
Cheol-jun also stared blankly at Kim Seong-cheol.
Then, he smiled brightly.
“I'll play it for you right now.”
“Ah, r-really?”
So that was the face.
The smiling expression Hyeong-man had bragged about, saying it made him melt instantly.
Seeing it in person, it was definitely worth bragging about.
It was truly pure and adorable.
Kim Seong-cheol forced an awkward smile onto his face and nodded.
Cheol-jun sat on the piano bench.
The math geeks took a step back, and Kim Seong-cheol quickly winked at his department chair.
The piano department chair rushed over and pushed the whiteboard far away.
“I'll begin. This piece is called the Minuet.”
A bright, cheerful piano melody echoed through the hall.
In truth, it was a very easy piece.
A simple tune that anyone could play as soon as they finished the basics of piano.
His posture wasn't very good either.
Kim Seong-cheol furrowed his brow slightly.
His finger shape and posture left much to be desired, but strangely, his rhythm was absolutely flawless.
He also knew how to control the dynamics quite well.
For someone who had only taken after-school piano classes for a month, he certainly had talent.
Or perhaps his piano teacher was exceptionally good at teaching.
Regardless, the performance of Mozart's Minuet—a piece he hadn't heard in so long he could barely remember—was quite decent.
When the performance ended, everyone applauded.
Cheol-jun stood up from the bench, bowed, and sat back down.
“And the piece I am about to play now is the one I back-calculated and estimated to be Wolfgang's original Minuet.”
Kim Seong-cheol raised an eyebrow and stared at Cheol-jun's fingers resting on the piano keys.
It felt like he was intentionally narrowing his hand span.
'Hmm, is he conscious of a five-year-old's finger span?'
Hearing whispering next to him, Kim Seong-cheol scowled deeply.
Those math people had absolutely no interest in the piano performance and were busy talking among themselves about formulas.
“He put the R-value here as an estimate, and the H-value is also an estimate. This is too vague to even use as a hypothesis. There are too many assumptions with weak evidence.”
“Still, it's incredible that he even got that far. If you isolate just that part, it's at the level of a math senior.”
“But he used too many variables. It seems the kid didn't know that the concept of preserving outliers to reconstruct the original piece can't be used in a formal proof at all.”
“Quantifying and restoring uniform intervals is a highly innovative method. The back-calculation logic is detailed enough to be applied elsewhere in the future.”
“Ahem!”
Kim Seong-cheol cleared his throat loudly on purpose.
The math professors, the department chair, and the dean stopped talking and glanced at Kim Seong-cheol.
“Well, the performer is waiting.”
“Ah, right, right.”
“Our apologies, Professor Kim.”
“Don't apologize to me, apologize to the performer.”
“Hahaha. Quite right. Well, student Cheol-jun? Shall we begin the performance?”
Cheol-jun, who had turned his head to scan the adults, grinned.
“Yes! I'll play the original piece again so you can compare, and then I'll immediately follow it with the piece I estimated through back-calculation!”
The performance began immediately.
The original piece they had just heard flowed out first.
And then, the piece of the five-year-old Mozart before it was edited, reconstructed through back-calculation formulas, followed right after.
It felt slightly different from the original.
It was clumsy in some places, yet something about it tugged at the heart.
The professors from the College of Natural Sciences tilted their heads,
the piano department chair stood dazed with his mouth half-open,
and when Cheol-jun's finger pressed the final key,
Kim Seong-cheol stared blankly, his mouth agape.
His lips were trembling slightly.