The fact was, he was here, like Kendal had said, based on a Rastafarian's description of a sweatshirt. He could have e-mailed someone, gone to Georgetown, or any of a number of things—
But he had driven to Cambridge.
He sat in the car, massaging his legs with his good arm and wondering if Magness had gotten him suspended yet. Am I here just because I have to do something?
What did he have? A name, "Mike," and a scrap of paper with a symbol that could mean just about anything . . .
And the possibility that the government was covering up something about the theft of a Daedalus supercomputer.
He was fooling himself if he thought he was going to find out anything here.
But, now that he was here, it really would be pointless driving back without trying, so he spent ten minutes maneuvering himself out of the car with his crutch.
A student, carrying a backpack and huddling against a severe wind, stopped and asked, "Do you need any help, sir?"
Gideon shook his head as he made it to his feet. "I've got it under control."
The kid turned to go, and Gideon called out, "Can you tell me where the mathematics department is?"
"Building two," the kid called back over his shoulder. "There's a directory over there." He hooked a thumb toward a nearby building, where a campus map stood.
"Thanks," Gideon said as he crutched over to the map.
"Fuck," he muttered. He had parked on the far side of the campus from building two.
Gideon looked up math professors at random. On the third try he found an office occupied. The office's occupant was named Doctor Harry Cho. Dr. Cho's door was ajar on a tiny office that was crowded with bookshelves and filing cabinets. Gideon knocked on the doorframe with his cast, letting the door swing all the way open.
Dr. Cho looked up from his computer and spun around. The movement startled Gideon before he realized that the professor was seated in a wheelchair.
"Can I help you?" Cho asked. Cho's expression was one of frank, almost embarrassing, curiosity.
Gideon extended his good hand and said, "My name's Gideon Malcolm. I'm a detective with the Washington D.C. Police Department."
Cho took his hand. "I hope I haven't done anything wrong, Officer."
"No—"
"D.C?" Cho looked at the cast and the crutch and said, "You aren't that cop from that Dateline story, are you?"
Gideon sighed and nodded.
"Well, what do you know?" Cho waved behind the door. "I have a chair—"
Gideon moved to sit down. It was a relief after walking across the campus. His leg and his shoulder were both giving him grief. He sat, massaging the scar-tissue crater through his pants leg. It felt, through the material, as if the hole went straight through his calf.
"It hurts?" Cho asked.
Gideon was almost embarrassed to admit it in front of someone in a wheelchair, but he nodded. "My leg was torn up pretty good." He patted the cast. "The arm was broken by the bullet, but it'll probably recover sooner than the leg."
Cho nodded. He slapped the side of his chair. "Anyway, what brings you here? A bit out of your jurisdiction."
Gideon shook his head. "I'm here on my own. I don't even know why I mentioned I was a cop—habit, I
guess."
Cho cocked his head and stared at Gideon with an expression that made him uneasy. It was as if all his doubts were visible on his face for Cho to see. He pulled out the paper with his hand-drawn aleph on it. It was severely crumpled now. "I'm interested in two things," he said staring at his paper. "The first is someone who might have been a student here, in Mathematics, Engineering, or—"
"Why are you looking for him?"
Gideon looked up from his crumpled paper. "What?"
"You said you were here on your own. Why are you looking?" He eyed Gideon suspiciously.
It took a while before Gideon said, "If you've seen any of the news stories, you should know why."
"It's about the Daedalus?"
"It's about why my brother was killed."
"And you think an alumni was involved?" Cho asked.
"It's a long shot." Gideon shook his head. "I really don't know what I'm doing here, but I can't stop looking for a reason. Something . . ."
"I understand."
Gideon shook his head and started to stand. "No, you don't have to talk to me. I'm not a cop right now, and I shouldn't even be here—"
"No" Cho said. He wheeled up and placed a hand on Gideon's cast, easing him back into the chair. "It's all right."
When Gideon was seated, Cho rolled back and said, "I know what it's like to go through something like that, to hunt for a meaning—but I should warn you, no one outside yourself can tell you why it happened. The most they can do is tell you how."
Gideon nodded. "This man, I believe he might have hired the driver for the Daedalus."
"Part of the terrorists the Secret Service was supposed to capture?"
Gideon nodded, though he wondered—if the ambush wasn't really Secret Service, what did that mean about the people they had meant to ambush.
"So who is he?" Cho asked.
"About six feet, two hundred pounds. Mid-twenties, white, blonde, named Mike."
Cho waited for a long time before he said, "Is that it?"
Gideon nodded.
"Well good luck. You know how many people go through MIT, and you don't even have a specific department to look in." Cho exhaled, "If you had a graduation date, or a year he was here, or even a less common name."
"I know," Gideon said. "I think I must have been half nuts coming all the way from D.C. This Mike had on an MIT sweatshirt—"
"That's it?"
"All I had to go on, yes." Gideon nodded. "But that's only half the reason I'm here. This, you might actually be able to help me with."
" We'll see. . ."
Gideon handed over his paper. "I've been trying to find out what this means. A friend of mine said it looked like a mathematical symbol."
Cho looked at the page for a few moments, as if deciphering Gideon's handwriting. Eventually, he nodded. "Your friend was right. What you have here is aleph-null."
Up to now, Gideon had been convincing himself that this whole trip was a waste. Despite that, when Cho identified the name of the symbol, Gideon felt a thrill. He had found something.
It meant something . . .
"What is it?" Gideon asked, his voice was rushed and breathless.
"It's the lowest class of infinity."
Gideon sat back, frowning. That made no sense to him.
"You've never heard of it, have you?" Cho asked.
Gideon shook his head, feeling as if the answer was just as cryptic as the unexplained symbol. It sounded like some New Age bullshit to him. "I thought infinity was infinity."
Cho handed back the paper and said. "That's a logical way to look at it. It seems so intuitively obvious, that the man who discovered—or invented, depending on how you look at it—the transfinite numbers was probably the least appreciated mathematical genius of the past five hundred years."
It was still all Zen to Gideon. "What does the lowest class of infinity mean?"
Cho leaned back and steepled his fingers a moment. "To explain that I'll have to give you some very rudimentary set theory—"
Gideon didn't like where this was going. "The last mathematics I had was trig in high school."
"Don't worry, this is fairly simple." He reached into the piles of papers on his desk and started dropping things in Gideon's lap—paper clips, rubber bands, pencils . . .
"Hey."
"There," Cho said, having placed three piles in Gideon's lap.
"What are you doing?"
"Some people need help visualizing." He smiled. "Now we have here three sets. For the sake of example, these piles are infinite."