Chapter 35

True transmission is one sentence; false transmission is ten thousand volumes.

If Lin Ran hadn’t directly pointed it out, Chen Jingrun might not have realized for many years that Professor Lin had packed dense mathematical knowledge related to intercontinental missile trajectory optimization into this mathematics seminar.

He finally understood why only young students were accepted, and not professors from Xiangjiang University.

On the surface, it was said he enjoyed interacting with the young and wanted to cultivate the next generation of Xiangjiang mathematics.

In reality, students struggled just to keep up—unless they were top-tier geniuses—but in this era, when Qiu Chengtong was still in elementary school, Xiangjiang had no such mathematical genius.

The possibility that students could discern the true meaning hidden in Lin Ran’s dense material was not merely minuscule—it was impossible—but professors might understand, especially those brought back from England.

Who knew the other’s past background? Had they aided Allied logistics in designing missiles during the war?

If the other had even a similar background, this possibility would surge rapidly.

“If we treat this system of partial differential equations as the flight trajectory of a ballistic missile, it would be affected by Earth’s gravity, air resistance, and other factors—this constant is undoubtedly Earth’s gravity.”

“This is air resistance, but what do the subsequent terms represent?”

“I understand it has been simplified into a linear recursive least-squares filter, but what is the application context?”

“Here, the formula is handled via a small-parameter expansion, reducing high-dimensional complexity into lower-order equations to cut computational load.”

“These should correspond to factors like air density variation and Earth’s curvature—so it directly answers Qian’s feedback on the first-order air resistance approximation equation!”

Chen Jingrun realized that the cases mentioned in Lin Ran’s class were like ore—some concealed gold within.

Among the dozens of cases, after analyzing them one by one, he found one that contained the solution to the mathematical problem Qian Xuesen had given him.

More importantly, the professor didn’t give a single value—he gave a universal model.

With this model, the original complex equations could be simplified into a linear recursive least-squares filter, and when combined with the piecewise constant error model taught by Lin Ran, approximate solutions for such problems could be computed by hand.

In his view, the approximate solution obtained this way would be at least two decimal places more precise than the original.

What once required massive manpower and might still fail to compute—even if computed, yielding only one decimal place—could now be approximated to three decimal places by ordinary manpower.

Though he wasn’t involved in missile design and didn’t grasp the formula’s significance, he knew this equation was the top-priority problem Qian Xuesen had given him.

That alone made it critically important to contemporary China.

Even if only this one equation existed, activating Channel 3 was justified.

Because, in his view, such an elegant method was one he had never seen in the most advanced mathematical journals at the Chinese Academy of Sciences’ Institute of Mathematics.

Though the journals that reached China were already far from the cutting edge—at least two years behind.

But since arriving in Xiangjiang and entering Lin Ran’s seminar, Xiangjiang University had granted them student-level access privileges, allowing him to consult the latest journals in the mathematics department’s library.

In those journals, he had found no similar method.

Now Chen Jingrun’s dilemma was: among the 37 cases, which ones held value?

He stayed awake all night.

The next day, with dark circles under his eyes, he went to class, then at eleven p.m. stood outside No. 8, Block 3, Kowloon Tong, eating a bowl of ramen until eleven p.m.

All shops on the street were closed; a Rolls-Royce P4 roared past, slowed briefly before him, then sped away.

In those three short seconds, Chen Jingrun had practiced exactly three hundred times in Yangcheng.

When the prepared file bag was precisely tossed through the window, Chen Jingrun finally relaxed—he had completed his mission.

He didn’t know that his life’s trajectory was about to be utterly transformed—that his mission wasn’t over, but just beginning.

“Old Qian, the Science Commission needs you to attend an emergency meeting.”

“The car is waiting downstairs!”

Qian Xuesen, already asleep, heard a sharp, brief knock at the door, then his wife rose to open it and woke him by his ear.

He sat up and glanced at the Wuyi wristwatch on his nightstand—it was 2:30 a.m.

What urgent matter could this be? He wondered—could it be related to Professor Lin Ran across the river?

Qian Xuesen quickly gathered himself and stepped into the night.

When he arrived at the Science Commission building, he found the blackboard densely covered with formulas.

“Come, Director Qian, please sit quickly—first, review this material.”

Qian Xuesen took the document from the man’s hand; after reading just two lines, he could no longer contain his excitement and walked to the blackboard.

“Yes, correct.”

“This uses Monte Carlo simulation.”

“Here, manual sampling is employed—only a mechanical calculator and manual sampling are needed to simulate randomness.”

“But what is this here?”

“No, this must have meaning—if Lin Ran bundled the entire algorithm together to teach it, this cannot be meaningless.”

“No, it could also be noise—introduced to conceal the true purpose.”

“No, Xiao Zhang! Quickly go to my office, right-lower drawer, and bring me my second notebook!”

“This is reminding us we can use Monte Carlo simulation—yes, this must be Monte Carlo simulation!”

Qian Xuesen stood before the blackboard, as if holding a silent dialogue with Lin Ran in Xiangjiang; the middle-aged man beside him, seeing Qian lost in thought, did not interrupt.

Long minutes passed, and Zhang Kewen still hadn’t brought the notebook; Qian Xuesen couldn’t resist walking to the side and lighting a cigarette.

Only then did the middle-aged man step forward: “Director Qian, what exactly is this Monte Carlo simulation you mentioned?”

Qian Xuesen explained: “During WWII, scientists in the Manhattan Project needed to solve complex physical problems like neutron diffusion, but analytical solutions were unattainable—so they devised this numerical simulation method.”

“Von Neumann and Stanislaw Ulam developed the systematic Monte Carlo method, using random sampling for numerical simulation, and”

“Nicholas Metropolis first named it Monte Carlo in 1947.”

“I’ve heard of this method—it uses manual sampling combined with mechanical calculators to simulate nuclear reactions—but they never showed me its specific details.”

“So it can be used to build nuclear bombs?” The middle-aged man’s eyes lit up.