An Unexpected Windfall!

The young engineer took out his computer, searched for a moment, and pulled up the PDF of the paper.

Engineer Tian took the laptop, squinted at it, and enlarged the text a little.

"Absolute Pruning Inequality and Asymptotic Convergence Theorem for Finite-State Game Trees"

When Engineer Tian saw the title, his expression grew serious.

The others in the reception room continued chatting, and no one noticed the change in his expression.

Engineer Tian first turned to the abstract and glanced through it, then moved on to the introduction. After reading for about half a minute, he turned to the main theorem in the third section.

Then he stopped.

He set the computer on the table, pulled a pen from his briefcase, and took a sheet of notepaper from the coffee table. He quickly wrote down several lines of formulas.

When he finished, he stared at the formulas for a while, then picked up the computer again and turned to the proofs later in the paper.

The people who had come with Engineer Tian were all his longtime subordinates. Seeing him like this, they stopped chatting.

"Old Tian?" the middle-aged man with glasses called tentatively.

Engineer Tian ignored him and turned two more pages before suddenly looking up.

"Xiao Zhao, that matter you reported to me about last month, the one about the search space explosion-where are you stuck now?"

Xiao Zhao was taken aback at being called on. "Well... once the branching factor goes up, pruning efficiency drops sharply. The alpha-beta approach is basically ineffective in our state space. We've tried several heuristics, but we can't provide a provable bound, and the verification team won't accept them."

Engineer Tian nodded. "You're still using Pearl's approach?"

"Basically. The math experts told us to do it that way."

Engineer Tian pointed at the computer screen. "No wonder you couldn't get it to work. A probabilistic framework was never suitable for your scenario. The node values are too strongly correlated, so the assumption that they're independent and identically distributed doesn't hold at all."

Xiao Zhao was somewhat at a loss for how to respond.

"The approach behind the Absolute Pruning Inequality in this paper is sound. He doesn't take the probabilistic route; he uses combinatorial extremal methods. In your problem, the states are deterministic, so you shouldn't have been using probabilistic methods in the first place."

"Old Tian, do you mean... this paper could be useful for our project?" The middle-aged man with glasses leaned closer.

"It should be useful. At the very least, we can use this inequality to verify the lower bounds of our current heuristics. If the bound he proved is tight, then we'll know the ceiling for further optimization. That would save more time than feeling our way through the dark."

"I estimate it could save us at least three to six months."

"That much?"

The others in the reception room all sat up straight.

"But Engineer Tian," Xiao Zhao said after a moment's hesitation, "isn't this paper suspected of fabricating its references? Everyone out there is saying those five Soviet references were made up."

Engineer Tian put his phone down on the table and laughed.

"How can you be so sure they were made up?"

"We couldn't find them online."

"There are plenty of things you can't find online."

Engineer Tian said unhurriedly, "I went to Russia once after the Soviet Union collapsed. In the Russia Academy of Sciences Library, there were entire cabinets full of old journals gathering dust, with no one looking after them."

"But that doesn't prove this paper wasn't faked, does it?"

"Let me tell you, you can tell whether a paper is fraudulent by looking at it."

"Look at the third section of this paper. He cites three lemmas from those five Soviet references and uses them in the construction of the inequality, the convergence proof, and the construction of a counterexample, respectively. These three lemmas aren't isolated; they're linked together with the derivations in the rest of the paper, each fitting into the next."

"If he made the lemmas up, either he couldn't make up ones that worked, or he'd use each one once and be done with it. He couldn't have made up three and woven them into a complete proof while keeping them consistent with one another."

"Then there are the five names he cited. The first two were the master and disciple behind AVL trees, who worked on combinatorial structures. The last three were part of that group at Moscow State University in the seventies, specializing in extremal analysis in game theory. Put those names together and you have a lineage of schools of thought. Someone making things up couldn't invent a genealogy like that."

"Lemma 3.2 on page seven of his paper was derived from Landis's work. I remember it-that result was later used by the Soviets in a completely unrelated field called nearest-neighbor search. If a first-year student really were faking it, could he fabricate things so thoroughly that even the background of Landis's work in the sixties fit together?"

The reception room fell silent for a few seconds.

The middle-aged man with glasses gave a wry smile. "Engineer Tian, your eye for this..."

"Enough flattery. It's not about having an eye for it. Anyone with a little common sense could have figured it out. I don't know why you thought the references were fabricated."

Everyone: ...

Big shot, are you saying we have no common sense?

Sure enough, no matter how old people got, they still got scolded by their superiors.

"This paper needs to be verified." Engineer Tian had no idea what the others were thinking and promptly assigned the task.

At that point, Xiao Zhao spoke up. "Engineer Tian, as you know, we've been trying another approach lately. All dozen or so people in the group are committed to that direction, and the milestones are already scheduled a month out. We really can't spare anyone."

"Then..."

"Huaji." Another senior engineer beside Engineer Tian, who had been silent until then, suddenly spoke.

Engineer Tian turned to look at him.

"We have people at Huaji."

"Huaji has been looking to establish a presence in artificial intelligence for the past two years. We've sent quite a few engineers over to exchange ideas with them. If it's urgent, we can have the engineers there find a way."

Engineer Tian nodded. "That's the right idea. Have them verify it, and we won't have to take people off our current project."

"Then let Xiao Zhao coordinate with the contact over there."

"All right."

Engineer Tian checked his watch and stood up. "Let's go. We won't wait any longer. The president probably won't be here anytime soon."

The group gathered their things and had just stepped out of the reception room when they ran into the vice president, who was hurrying toward them down the corridor.

When the vice president saw that they were leaving, his expression changed. He hurried forward. "Engineer Tian, everyone, I'm terribly sorry. A student matter came up that the president had to deal with. He'll be here in fifteen minutes at most."

"There's no need." Engineer Tian's manner was calm. "We're just about out of time ourselves. We didn't get to discuss what we came for this time, so we'll talk another day if there's a chance."

The vice president looked apologetic. "Engineer Tian, we really failed to receive you properly this time..."

Engineer Tian smiled. "Actually, this visit gave me an unexpected windfall."

"Huh?" The vice president was taken aback. "What?"

Engineer Tian didn't explain. He simply patted him on the shoulder. "When the president gets back, tell him today's trip wasn't wasted."

With that, the group left.

The vice president stood there, completely bewildered.

What unexpected windfall?

After the president finally finished dealing with the people from the mathematics school, he came to the reception room.

The vice president immediately went up to him. "President, Engineer Tian and the others from Institute 611 have left."

"They left? Ah, what timing today. Did they say anything..."

"Before he left, Engineer Tian said this visit had given him an unexpected windfall."

The president stopped in his tracks.

"An unexpected windfall? What unexpected windfall?"

"I don't know either. He didn't say what it was."

The president frowned. "We left them sitting in the reception room for over an hour today. What unexpected windfall could he possibly have gotten? We'd be lucky if he didn't curse us out."

"Then was he being sarcastic?" the vice president asked tentatively.