Prodigy’s Playground

Chapter 87 The Promise

Mid-June.

Universities across Dragon Country entered exam week one after another. Students gradually became busy.

Jiang Ran was no exception.

His student life in the 2045 prison had also reached its end.

“I’ve noticed—you’re very sharp. You grasp things instantly.”

In front of the mottled white wall, the elderly Zhang Yang looked at Jiang Ran in genuine surprise.

“Although the proof of Goldbach’s Conjecture isn’t particularly difficult, the fact that you mastered it from beginning to end in just one hour—there’s definitely mathematical talent there.”

He sighed, regret flickering in his eyes.

“And yet, with such talent, you strayed off the path and ended up wasting your life in prison. What a pity…”

Then he gave a self-mocking smile.“But I’m hardly qualified to lecture you. We’re all the same.”

During this period, Jiang Ran’s routine had become rigidly fixed.

Including his trips to the year 2045 via the Positron Cannon.

Each time he opened his eyes, he would quietly sit in a corner and watch Sang Biao’s furious solo performance.

Then, once Sang Biao stormed off and threw the silver wire to the ground, Jiang Ran would retrieve it and toss it to the tool man in Cell No. 5—

The Killer.

Like Doraemon, the Killer seemed capable of everything. His lock-picking skills surpassed even Sang Biao’s.

After that came the same monotonous hours every day.

Jiang Ran and Zhang Yang sat on the floor discussing mathematics.

The Killer leaned silently against the bars behind them.

Hothead occasionally threw punches at the air, as if battling invisible enemies.

The deeper Jiang Ran went into the mathematics, the more he felt the overwhelming brilliance of Lu Yu.

How exactly was that brain constructed?

The elegance of the reasoning. The perfection of the derivation.

It inspired nothing but admiration.

Fortunately, the proof method was concise.

If it had been overly complex and tedious—

Jiang Ran would never have mastered it in such a short time.

“Thank you, Professor Zhang.”

Jiang Ran spoke sincerely.

They say a teacher for a day is a father for life. Jiang Ran had no intention of forming a paternal bond—but the respect and gratitude were genuine.

Whether it was the promising young Professor Zhang Yang of 2025—

Or the fallen, imprisoned Professor Zhang Yang of 2045—

In Jiang Ran’s heart, he would always remain a teacher worthy of lifelong respect.

Today—

Under Professor Zhang Yang’s supervision, Jiang Ran independently derived the complete proof of Goldbach’s Conjecture from beginning to end.

The explanation was coherent.

The logic clear.

The structure sound.

No errors.

At last—

This halfway mathematician had graduated.

He stood up.

And bowed deeply.

“Professor Zhang, thank you for your guidance. Truly.”

The bow startled Zhang Yang.

“What are you talking about?”

He laughed helplessly.

“We’ve known each other less than two hours. What ‘guidance all along’? I have no idea what you’re saying.”

“Honestly, I just listened while you reviewed it. You must have studied Goldbach’s Conjecture before prison. I was just a listener. It’s your own talent.”

Jiang Ran said nothing.

Talent?

He had none.

What he had were days and nights of patient instruction.

In the eyes of the white-haired old man before him, they had known each other barely an hour.

But to Jiang Ran—

It had been more than ten days and nights of tireless study.

“Professor Zhang, I have another question.”

Jiang Ran straightened.

“When Lu Yu published his results, how did he do it? Did he submit directly to journals?”

“Not exactly.”

Zhang Yang shook his head.

“He handed the manuscript directly to the academic director of the Dragon Country Academy of Sciences. The university helped publish it under his name.”

He paused.

“Later, Lu Yu regretted that.”

“Once the breakthrough was announced, he became a globally recognized genius overnight. It severely disrupted his life.”

“Wherever he went, people followed him. Interviews. Photos. Crowds.”

“Even during class, admirers would show up asking for autographs and pictures.”

“It affected his normal study and daily life.”

Jiang Ran nodded.

So that was how it had happened.

He had asked because he feared precisely this scenario.

After all—

This was Goldbach’s Conjecture.

A problem that had troubled humanity for centuries.

In the era of the internet, it would catapult anyone into instant global fame.

The consequences were obvious:

Either endless scrutiny and inconvenience.

Or state protection and confinement to research.

Either way, Donghai University would no longer be a peaceful campus.

And that—

Was not what Jiang Ran wanted.

He carried too many secrets:

The Positron Cannon.

Time-traveling text messages.

The year 2045.

The spacetime shuttle.

If he publicly announced a proof of Goldbach’s Conjecture, he would be trapped under countless eyes.

The Positron Cannon would become unusable.

Every subsequent plan would grind to a halt.

So—

How to publish this world-shaking achievement required careful thought.

“The Dragon Country Academy of Sciences…”

Jiang Ran murmured.

“At least there, things would be handled properly. It’s the top research institution in Dragon Country.”

His eyes blinked.

Suddenly—

“Professor Zhang! Your teacher—isn’t he the president of the Academy? I remember you were Academician Gao Yan’s last disciple!”

At the mention of the past, the elderly Zhang Yang smiled faintly.

“Let’s not bring that up. I’ve disgraced my teacher.”

But Jiang Ran had already found the optimal plan.

He had never intended to gain fame or wealth from Goldbach’s Conjecture.

All he wanted—

Was a recommendation letter to Donghai University.

He didn’t care about authorship.

He didn’t care about credit.

He just needed the letter.

So instead of publicly publishing the proof—

Why not send it directly to Academician Gao Yan?

Let the Academy handle it.

He didn’t need recognition.

He didn’t need his name attached.

Let the Dragon Country Academy of Sciences take it entirely.

As for what happened afterward—

He neither cared nor intended to interfere.

His only small request—

That Gao Yan, along with two other academicians, write him a joint recommendation letter.

Recommending a mathematician who solved Goldbach’s Conjecture to Donghai University—

Was entirely reasonable.

Entirely justified.

Entirely compliant.

At that moment—

A faint tremor passed through the ceiling and floor.

Distant thunderous shouting followed.

Jiang Ran was familiar with this sound.

The hood had been removed.

The crowd was roaring for the beheading of the enemy of humanity.

Which meant—

In about two minutes—

The blade would fall.

And Jiang Ran—

Would return to 2025.

“It’s time to say goodbye, Professor Zhang.”

Zhang Yang blinked.

“Where are you going? After Sang Biao?”

“No.”

Jiang Ran shook his head.

“I’m going back.”

The Killer clenched his fist nearby, eyes fixed on him.

“Back?”

Zhang Yang was still confused.

“Back where? To your cell?”

Jiang Ran smiled but did not answer.

He helped the elderly man to his feet and brushed dust from his clothes.

“Professor Zhang, thank you for teaching me so patiently. I will find a way to repay you.”

That made Zhang Yang laugh outright.

“Repay me? It was nothing.”

“And we’re prisoners. Nothing changes. One day at a time.”

“I will repay you.”

Jiang Ran’s voice was firm.

The best way to repay him—

Was to prevent him from ever researching quantum tunneling twenty years earlier.

In previous loops, Zhang Yang had said it was deep involvement in quantum tunneling research that led to his imprisonment.

If Jiang Ran could stop that—

Perhaps this prison cell would stand empty.

Or perhaps someone else would occupy it.

But the brilliant, gentle Zhang Yang of youth—

Would not age into this white-haired prisoner.

“Goodbye.”

Jiang Ran clasped the old man’s withered hand.

“I hope we never meet here again.”

Buzz.

Buzz.

Buzz.

The world twisted.

Vertigo.

Darkness.

Rotation without end.

Two seconds later—

The discomfort vanished.

Jiang Ran opened his eyes beside the transformer distribution box.

Right on time.

“Next step—find Academician Gao Yan’s email.”

Laptop connected to Wi-Fi.

Search.

The Academy’s official public inbox was easy to find.

But it received endless submissions from self-proclaimed “folk scientists.”

Perpetual motion machines.

Refutations of Fermat’s Last Theorem.

Daily “proofs” of Goldbach’s Conjecture.

Those emails would never be read.

They were auto-replied and redirected to academic journals.

That process would take months.

Jiang Ran did not have months.

And public journals would reintroduce the fame problem.

He needed discretion.

Gao Yan’s private email would be ideal.

But as president of the Academy—

It was not publicly available.

As his last disciple, Zhang Yang would know it.

But in this worldline, Jiang Ran’s relationship with him…

He coughed.

Better not.

After stabbing someone with a pencil in a previous loop, asking for their mentor’s private email would be absurd.

Fortunately—

After persistent searching—

He found the assistant email for one of Gao Yan’s research projects.

Good enough.

If no reply came in a few days, he would consider alternatives.

He copied the address.

Pasted it.

Attached the compiled manuscript proving Goldbach’s Conjecture.

Included his information, intent, and contact details.

And clicked send.

“Off you go.”