Shen Moxin’s fingers tightened on the manuscript, then loosened.
Taking a deep breath, she gently placed the yellowed paper back on the shelf, turned, and stepped lightly around the corner.
Lu Yuan was still sitting in the corner, his head lowered.
His fingers hovered over the open manuscript, tracing something aimlessly in the air.
“Could you elaborate?” The voice spoke from just ahead to his side.
Lu Yuan snapped back to reality, curling his fingers back into his palm.
When he looked up, Shen Moxin was standing a few paces away, one hand resting against the bookshelf.
Her expression was neutral, but behind her glasses, her eyes burned with an intense, sharp focus.
His heart tightened.
*I spoke out loud.* His previous mumbling had been kept extremely quiet—a habit of muttering to himself.
He hadn’t expected anyone to hear him through a row of bookshelves, let alone this assistant teacher.
Shen Moxin didn’t push him.
She stepped forward twice and stopped opposite the desk, her gaze landing on the hand-drawn decay curve on the manuscript.
“You said just now that the model ignored the interference factor of the environmental soul force field.” Her voice was steady, as if simply restating a fact.
“You also mentioned that the decay constant becomes a variable.” She tapped her fingernail gently against the tabletop.
“I’m curious.
Which kind of interference were you referring to?
And how does it change?” Lu Yuan looked at her.
Her eyes held inquiry and wonder, but no mockery whatsoever.
He had seen too many mockingly cold glances—in Maple Leaf Town, at the city gates, at the foot of the library steps.
But Shen Moxin didn’t have that look.
He paused to consider.
*An opportunity.
Or maybe trouble.* “Simply put,” Lu Yuan began, his voice steadier than usual as he reached out and pointed at the curve on the manuscript, “this record assumes that after martial soul energy is released, its rate of decay in the environment is constant.
That’s why it uses an exponential decay model to fit a fixed decay constant, α.” Shen Moxin nodded.
This was a foundational model from the textbooks.
“But there’s a flaw in this assumption.” Lu Yuan’s finger slid down the curve.
“It defaults to the assumption that environmental soul force density is uniform and stable.
But in reality…” He paused, pulled a charcoal pencil from his robe, and drew out a piece of scrap paper he had brought himself.
Shen Moxin noticed that the margins of the paper were densely packed with small characters and symbols.
Lu Yuan drew two axes on a blank spot: the horizontal axis representing time, and the vertical representing soul force intensity.
First, he quickly sketched a downward curve similar to the one on the manuscript.
“If the environmental soul force density really were constant, fitting the data like this would be fine.” As he spoke, he drew a second line alongside it—one that fluctuated up and down.
“But in a real environment, soul force density fluctuates.
For example, if nearby Spirit Master are cultivating or releasing soul skills, or even if the weather changes, it affects the density.” He marked several points along the fluctuating line.
“At these nodes, the environmental soul force density suddenly spikes or drops.
Consequently, the ‘resistance’—or ‘dilution rate’—acting on the energy released by the martial soul during its decay process will change.” The charcoal pencil returned to the first decay curve.
At several corresponding points, he paused lightly.
The smooth curve instantly took on several unnaturally steep or flat breaks.
“Look here,” Lu Yuan said, pointing at a spot on the manuscript’s curve that should have transitioned smoothly but appeared somewhat rigid.
“The recorder probably wrote it off as measurement error.
But if we introduce an interference factor, β, that varies with the environmental soul force density…” He quickly jotted down a rough formula on the paper: α’ = α ± k·β(t).
His handwriting was hurried, but the structure was crystal clear.
“Then the decay constant α is no longer a constant, but a time-dependent function, α’.
If you re-fit the data using this revised model…” His charcoal pencil made a light tracing motion.
“…these seemingly contradictory data points on the manuscript actually connect into a far more reasonable curve.
The margin of error becomes much smaller.” He set down the pencil and looked up at Shen Moxin.
Shen Moxin said nothing.
Leaning forward slightly, she stared at the scrap paper, her eyes moving back and forth between the curves, the formula, and the manuscript.
Her hand rose unconsciously to push up her glasses.
The library was quiet, save for the faint, distant rustle of turning pages.
Several breaths passed.
“A dual-variable impact model…” Shen Moxin murmured as if to herself.
She raised her head, looking at Lu Yuan with a complex gaze.
“Environmental soul force density fluctuation as a second variable, interfering with the core decay process…
This line of thought…” She didn’t finish her sentence, but Lu Yuan read her shock clearly.
The model wasn’t deeply complex, but it broke away from the traditional, rigid mindset in the Spirit Master world that treated energy decay as an “isolated system.” The vast majority of researchers—including herself—defaulted to treating energy released by a martial soul as if it decayed in a vacuum, writing off environmental influences under the broad blanket of “experimental error.” Yet the poorly dressed child before her had sketched out a framework that was not only logically self-consistent, but directly resolved several data contradictions in that old manuscript—contradictions she herself had previously found awkward, yet couldn’t quite explain.
Shen Moxin took a deep breath.
“This interference factor, β—how do you determine its mathematical form?
And the coupling coefficient, k—does it depend on the type of martial soul?” Her questions were sharp, targeting the core of the model.
Lu Yuan breathed a quiet sigh of relief inside.
She was seriously considering the theory, not rushing to dismiss it.
“The exact form of β requires reverse-engineering from actual measurements of environmental soul force fluctuations; right now, it can only be a hypothesis,” he said, choosing his words carefully.
“As for k…
it definitely relates to the characteristics of the martial soul.
For instance, fire-attribute energy will decay at different rates in humid environments versus dry ones.
But determining that coefficient would require a large number of controlled experiments.” He was telling the truth, and he was pointing out the difficulty.
The model was merely a crude framework.
Shen Moxin understood.
The light in her eyes grew brighter—an excitement born of meeting an equal and glimpsing an entirely new path.
A research bottleneck that had plagued her for a long time seemed to have been cracked open by these few sentences.
She couldn’t help asking further, “If we follow your line of reasoning, then many traditional evaluations of soul skill power, soul force consumption calculations, and even energy impact models during soul ring absorption would all need to…” Before she could finish— A heavy set of footsteps echoed from the entrance of the reading area, approaching from a distance.
Both of them looked up simultaneously.
The stern-faced, middle-aged administrator walked over, holding a register in his hands.
He first swept his gaze over Lu Yuan, his brow furrowing out of habit, before looking at Shen Moxin.
His tone was stiff.
“Assistant Shen, your time is up.” He pointed to an unobtrusive hourglass on the wall; the fine sand inside had just finished draining.
“Half an hour, not a minute more.” Only then did Shen Moxin realize how much time had passed.
She glanced at the open manuscript in front of Lu Yuan and the scrap paper filled with formulas, a surge of intense reluctance rising in her heart.
But she knew the rules.
“Alright, I understand,” she nodded, beginning to gather the stack of materials she had brought.
The administrator didn’t leave immediately.
His eyes circled back to Lu Yuan, the corners of his mouth turning downward as he lowered his voice.
“Also, the Director asked me to remind you—bringing unauthorized personnel into the inner area for consultation is against the regulations.
We’ll let it slide this time, but don’t let it happen again.” When he said “inner area,” he put extra emphasis on the words.
Only then did Lu Yuan notice a small sign posted at the entrance of this bookshelf area that read: *Research Materials Area: Assistant Teachers and Above Only.* Shen Moxin’s movements paused.
She looked up at the administrator with an expressionless face, but her voice was steady and clear.
“He came in with me, and the materials consulted were within allowed parameters.
The responsibility is mine; I will explain it to the Director.” The administrator choked on his words, clearly unprepared for Shen Moxin taking the blame so directly.
He twitched the corner of his mouth, turned, and walked away.
In the small corner, the atmosphere felt somewhat tense.
Shen Moxin quickly jotted down the titles of a few manuscripts she might need in her leather notebook.
Then she looked at Lu Yuan, her speaking speed picking up.
“You need to leave.
Go through the side door, not the main entrance.” Lu Yuan didn’t waste words.
He immediately stood up, carefully closed the manuscript, and returned it to its original spot.
He hesitated over the scrap paper covered in formulas, then crumpled it up and stuffed it into his tunic.
He stowed the charcoal pencil.
His movements were nimble and efficient.
Watching him, Shen Moxin could no longer hold back the question in her mind.
Just as he turned to leave, she suddenly spoke, her voice soft yet carrying unprecedented gravity: “Wait.” Lu Yuan stopped and turned around.
Shen Moxin looked at him, her eyes behind her glasses as sharp as blades.
“These ideas…
about the model, about the soul force field,” she asked word by word, “who taught them to you?” Lu Yuan remained silent.
Sunlight shifted onto the side of his face.
His lips pressed together.
Just as he was about to speak— “Assistant Shen!” The administrator who had just left returned, standing a few rows of bookshelves away.
His voice was even harsher than before.
“The Director wants to see you right now.
Immediately.” Shen Moxin’s expression changed slightly.
Lu Yuan glanced at her, said nothing, and simply gave a subtle nod.
Turning on his heel, he walked briskly down the shadows between the bookshelves toward the side door.
His figure quickly vanished.
Shen Moxin stood in place, her fingers tightly gripping the edge of her notebook.
The Director summoning her so suddenly, and sending the administrator to urge her twice…
it was likely more than a simple “reminder.” She withdrew her gaze and looked at the spot where Lu Yuan had been sitting.
The tabletop was empty.
Yet that crude dual-variable model—and those calm, un-childlike eyes—were already deeply burned into her mind.
Closing her notebook, she turned and walked toward the administrator.
Her steps were steady.
Inside, however, her heart was like a deep pool into which a stone had been cast; ripples spread outward in circles, impossible to calm.