"Next, we will enter the free discussion segment. If you have any thoughts, you may raise them and interact with Elder Su."
The crowd was eager to participate, and over a dozen hands shot up high into the air.
"Teacher Su, I’d like to ask a question."
The microphone was passed to the middle of the seating area, where a boy who looked like a STEM major stood up.
"Regarding the concept of ’Subtraction’ you advocate, I can understand it as a warning against being kidnapped by our desires, which is great. But in your speech just now, you expanded this idea to the societal level, suggesting we slow down technological development. The reality is that many problems can only be solved by cutting-edge technology. Applying Subtraction here—isn’t that an anti-intellectual and anti-science viewpoint? Isn’t it a rejection of progress? Did you arrive here today in a horse-drawn carriage?"
A low murmur of laughter rippled through the audience.
Yu Xian heard a nearby teacher softly tut. He wondered if the teacher felt the student’s teasing was too aggressive and unbecoming of JCU’s grace.
The host’s smile stiffened slightly. Just as they were about to smooth things over, Su Mingyuan raised a hand to indicate it was fine.
"Good question. As expected, JCU has no shortage of people who think deeply and dare to speak up," he smiled and continued. "I’m not a fossil, nor do I deny that science and technology have brought many conveniences to our lives."
Changing the subject, he looked at the boy who had asked the question. "However, there is a term called ’diminishing marginal returns.’ I don’t know if you’ve heard of it, but it’s a fundamental concept in economics."
Yu Xian paused, not expecting the older man to approach the topic from this angle. He knew the meaning of the term; it referred to how, as resources were continuously poured into a certain endeavor, the resulting increase in effectiveness would steadily decline.
"Let me give an example that might not be perfect. I saw many students taking photos just now. Many smartphone cameras today have a ’RAW Image’ mode, which you young people surely know about. What are the benefits of RAW mode? It retains more information and provides greater room for post-processing." Su Mingyuan paused, his gaze sweeping across the audience. "But when you send this photo to your parents or post it to your Friends Circle, do you send the original RAW file?"
Some people in the audience shook their heads, while others softly answered, "No."
"Right, you wouldn’t. Because it’s too large. A single photo can easily take up over a hundred megabytes, or even several hundred. It’s slow to transmit, takes up storage, and is simply unnecessary."
On stage, Su Mingyuan spread his hands. "We compress it into a JPEG, instantly reducing a photo to just a few megabytes—a mere fraction of its original size."
His shadow stretched long by the stage lights, Su Mingyuan turned back to the boy and spoke slowly. "So, I ask you: when you send this compressed photo to your mother, will the joy she feels be diminished just because the image lost 95% of its data?"
"...No, not really."
"Exactly. That’s because the core information—your smiling face and your safety—is perfectly preserved. The 95% that gets compressed away is the part with extremely low marginal utility; it’s a redundancy with a very low ’signal-to-noise ratio.’ This feature isn’t everyone’s default option, either.
"The development of society and science is the same. Resources are not infinite. Take today’s event, for example. The staff worked very hard, piling on the lighting, audio, live streaming, and stage setup. The results are indeed better. But as you can see, for this little bit of ’premium feel,’ who knows how many extra staff members were required on site? How many more days did the students have to work, and how many all-nighters did they pull? How high are the marginal returns of all that?"
Leaning against the doorframe of the side entrance, Yu Xian watched the scene unfold from afar. The boy who had asked the question slowly lowered his hand.
Yu Xian shrugged. Mr. Su had hit the nail right on the head—wasn’t he exactly one of those extra staff members?
"Learning to apply ’lossy compression’ isn’t so much anti-intellectual as it is optimization. The same goes for Pareto optimization in economics."
Thunderous applause erupted. The students and faculty of JCU did not skimp on their praise for Elder Su.
Over the next half hour, a few more people asked questions, including a teacher from JCU. Elder Su answered them one by one in a convincing manner, and the questioners sincerely thanked him for his teachings.
The event eventually drew to a close amidst lingering sighs of reluctance.
"Perfect! Absolutely perfect! It really blew up!"
Just as the crowd began to disperse, Shi Zuozhou hurried over, his face flushed with excitement like a general who had just won a major battle. "The live stream made it to the trending list, and the video’s view count is the highest the JCU Student Union has seen all year!"
Packing the sample books and the sign-in QR code into a box, Yu Xian looked at Shi Zuozhou’s hyperactive expression. He really wanted to ask him, "Mr. Su told everyone to practice Subtraction, but you didn’t take a single word of it to heart, did you?"
Not having the heart to rain on his parade, he swallowed his words instead. Right. Unnecessary truths were also a form of redundancy. Time for Subtraction.
Most of the people in the auditorium had left. Only the Student Union members remained, dismantling the display boards and packing up supplies.
Carrying the cardboard box from the sign-in desk, Yu Xian prepared to move it to the backstage storage room. As he passed the side of the stage, his footsteps faltered.
Su Mingyuan was standing there holding a thermos, seemingly talking to someone. Standing opposite him were, surprisingly, two girls with double buns.
The girl with the cartoonish double buns appeared slightly reserved, nodding frequently as she listened to Elder Su speak. The girl with the classic double buns was much more uninhibited. Standing beside Su Mingyuan, she seemed to be complaining to the old man about something.
Given the distance and the PITTER-PATTER of the rain against the windows, Yu Xian couldn’t hear what they were saying. Retracting his gaze, he carried the box toward the storage room.
By the time he finished tidying up and came out, he happened to run into Su Mingyuan and the two bun-haired girls at the lobby’s side door. A black commercial van was parked outside, its electric door slowly sliding open.
Perhaps noticing the "Staff" badge hanging around Yu Xian’s neck, Elder Su paused for a moment. He didn’t say anything, merely giving a slight nod. Yu Xian subconsciously nodded back in response.
By the time he registered the interaction, Su Mingyuan had already bid farewell to the two girls and bent down to get into the car. The vehicle drove off into the curtain of rain, leaving behind a trail of red taillights.
Just as Yu Xian was about to look for Shi Zuozhou to see if there was any more work to be done, a figure stepped sideways, blocking his path.
"Brother Cos, hold on a second."
It was the girl with the classic double buns. Despite her somewhat demure outfit, her smile carried a hint of mischief. Beside her, the girl with the cartoonish double buns—the Uncertainty Robot—looked like she wanted nothing more than to bury her face in the collar of her hoodie, one hand secretly tugging at her companion’s sleeve.
"Can I help you?" Yu Xian felt that this scene was somewhat familiar, as if it had happened somewhere before.
"Ahem. It’s nothing major. I just thought it was fate that we met here. Since we’re all fellow ACG enthusiasts, how about we add each other on WeChat? We could cosplay together at anime conventions in the future."
Yu Xian’s brow twitched. "Who’s your fellow ACG enthusiast?"
He opened his mouth, wanting to explain that the meaning of his nickname was "cosine," not "cosplay."
"Hey! What a coincidence!"
Before he could speak, an enthusiastically loud voice suddenly chimed in from behind. Shi Zuozhou had popped up out of nowhere, still seemingly immersed in the excitement of the event’s success.
"So you two juniors are also fellow enthusiasts! I knew it! Looking at your outfits, you’re cosplaying... Wait, don’t tell me, let me guess! Is it Kagura? Or are you cosplaying Akatsuki Hatori? Did I get it right?!"
Not even giving Yu Xian a chance to open his mouth, Shi Zuozhou whipped out his own phone, pulled up Yu Xian’s profile, and shoved the screen right in front of the girl with the classic double buns. "Add him! You absolutely have to add him! Even though I’m his roommate, this is my first time finding out he has this hobby too! Here, this is his contact card."
"..." Yu Xian was utterly shell-shocked. Seeing Shi Zuozhou’s smug expression that practically screamed, *I’m setting you up, bro,* he felt a deep wave of powerlessness.
The girl with the classic double buns was clearly satisfied with this outcome. Her smile grew even brighter, and she even added Shi Zuozhou as a friend while she was at it.
The phone in his pocket buzzed. Yu Xian sighed inwardly and pulled it out in resignation. A new friend request popped up on the screen. His finger paused. He looked at the name on the friend request, then looked up at the girl with the classic double buns in front of him.
"You are this... AAA Divine Calculation Immortal (Seclusion Edition)?"