420: Chapter 870 Secret Schemes!

"Just keep a closer watch, that's all."

Zhao Yang said calmly to Wang Hai.

Wang Hai nodded with a solemn expression. Having followed Zhao Yang for so long, he had long since figured out the temperament of this young professor.

The more dangerous the situation, the calmer Zhao Yang became—so calm that sometimes Wang Hai felt he was better suited for security work than he was himself.

Zhao Yang was fully prepared for the fact that he would be targeted while abroad.

Back when they dismantled that transnational spy network at the Aerospace Center, Shin-chan had dug up several intelligence assessment reports targeting him personally from those servers.

Those reports listed him as a "target requiring priority processing."

Therefore, from the moment he boarded the flight to Seoul, he knew that it was highly probable he had already been targeted by someone.

The person in the gray hoodie at the plaza just now, and that "customer" at the convenience store by the hotel entrance who had been reading a newspaper for forty minutes without buying anything, were both parts of this chain that had been exposed.

The lights in the lecture hall dimmed, and the projector screen lit up.

The speaker for today's presentation was the German mathematician Schultz, and the topic was a phased achievement regarding the Four Color Theorem.

Schultz was a rising star who had emerged in the European mathematical community in recent years; his doctoral thesis was on p-adic geometry, which had caused quite a stir in the circle at the time.

He stood on the podium, explaining his proof framework page by page in English with a German accent.

Zhao Yang sat in a front-row seat, his right hand resting on the armrest, his fingers tapping lightly against it.

When dealing with the Four Color Theorem, Schultz introduced a new graph theory reduction method. This method was somewhat similar in mathematical structure to a boundary compression technique he had previously used in the construction of the normal cone of a Polynomial Ideal.

His brain began to automatically deduce what would happen if he slightly modified this reduction method and substituted it into his own framework of Polynomial Ideals.

Wang Hai, sitting next to him, couldn't understand a word of what was being said on stage; his eyes were fixed on everyone entering the lecture hall.

He remained in a state of high alert at all times.

After the presentation ended, the lights came back on.

Zhao Yang stood up from his seat and was just about to walk out when he heard someone behind him calling his name in English with a German accent.

Schultz walked quickly down from the podium, wove through the crowd that was still packing up their things, and stopped in front of Zhao Yang.

He was a tall man with slightly curly hair, and there was a hint of surprise in his eyes as he looked at Zhao Yang.

He also hadn't expected that the famous Professor Zhao would actually come to see his presentation.

"Professor Zhao, please wait a moment. Just now, when I was talking about the reduction method, I noticed you seemed to be writing something on paper, and I'm very curious. Do you have any thoughts on this direction of the Four Color Theorem?"

"I have a few. Your graph theory reduction shares some common ground in structure with a boundary compression technique I previously used within the Polynomial Ideal framework. If you slightly modify your reduction method and substitute it into the polynomial framework, you might be able to derive a tighter bound."

Zhao Yang pondered for a moment before saying.

Schultz's eyes lit up.

"That's exactly what I was thinking! My reduction method still has some slack when dealing with certain boundary conditions. If it could interface with your polynomial framework, perhaps those slack points could be tightened. Are you interested in this topic? We could collaborate. I have the foundation in graph theory and combinatorial optimization, and you have the framework of Polynomial Ideals and Algebraic Geometry. If the two directions could be bridged, perhaps we could really push past the final step of the Four Color Theorem."

"I'm afraid I don't have the time for now. I have several projects in progress at the same time, and my energy doesn't really allow for starting a new direction."

Zhao Yang spread his hands and shrugged.

For him, there was too much that needed to be done, and he didn't have that much time to waste on this.

"That's alright."

Schultz wasn't disappointed; he smiled as he looked at Zhao Yang and said.

"I can organize my current work and send it to you first, and you can take a look when you have time. If you have any thoughts, we can discuss it then."

"That's no problem."

Zhao Yang agreed.

The two of them exchanged email addresses.

Leaving the lecture hall, Zhao Yang took Wang Hong and another student toward the exit of the convention center.

He no longer intended to continue listening to the subsequent reports, even though there was still one on random matrix theory on the schedule.

The speaker was an old professor from Oxford who was quite famous in the circle, but his research had little intersection with his current area of study.

Rather than wasting time here, it would be better to return to the hotel earlier.

Just as they walked to the entrance of the convention center, a group of Korean students surrounded them outside.

Some were holding up photos of Zhao Yang receiving his award at the International Congress of Mathematicians; some held markers, and some were shouting "Brother Yang" in broken Chinese.

Wang Hai immediately stepped forward to block the way in front of Zhao Yang, and another accompanying security guard sealed off the passage from the side.

"Sorry, Professor Zhao is not accepting autograph requests right now."

Wang Hai said it once in Korean and repeated it in English.

Zhao Yang did not stop.

Escorted by Wang Hai and the security personnel, he quickly passed through the crowd.

Leaving the convention center and on the way back to the hotel, Wang Hai's tone was even more solemn than it had been in the lecture hall.

"Professor Zhao, there are several times more people in the plaza today than there were two days ago. And those few suspicious ones mixed in the crowd have changed their positions and clothes; they're disguised well, but I still found clues."

"Even in the lecture hall, there were a few people watching you!"

"They're probably getting anxious too."

Zhao Yang leaned back in his seat, his gaze calm, and said indifferently.

"The International Congress of Mathematicians is almost over; there aren't many windows of opportunity left for them to make a move."

After watching Zhao Yang and his group disappear around the street corner, that Asian face in the crowd turned and walked into a narrow alley next to the convention center.

A gray van was parked in the alley, with no markings on the body.

He opened the door and climbed inside. Inside the van, several people were sitting around a folding table, on which were a few laptops and a set of encrypted communication equipment.

The leader was a white man with extremely short hair, staring at the floor plan of the hotel on the screen.

"The target's vigilance has increased. He didn't stop at all when he came out of the convention center; he used to sign autographs for fans. Also, that bodyguard was observing the surroundings the whole time in the lecture hall today. His attention wasn't on standard security; he was looking for people."

"Have we been exposed?" asked a person wearing headphones nearby.

"Probably not yet. But the people around him have already sensed something is wrong. We'd better not drag this out."

The leader was silent for a moment, then stood up and stubbed out his cigarette in a plastic cup nearby.

"Proceed with the second plan. Are the people inside the hotel ready?"

"They are in position. The compartment in the room service cart can hide a tranquilizer and a change of clothes. But after the target returned to his room just now, he didn't call for any room service. The bodyguard deregistered the key card from the hotel system and replaced it with a physical deadbolt they brought themselves. They now have their own people rotating shifts at the door 24 hours a day."