Root of Unity (2 page)

“And she’s good at subtle,” Arthur agreed. “Shit. Well, I’m in luck then, ’cause I might have a job for you, and looks like you’re available.”

“Ha. I don’t need your charity.”

“Ain’t charity. Client knows I need an assist on this. Your rate’ll be met.”

I squinted at him, but his face was serious. “You gonna let me work it my way?”

“Not a chance in hell. You in?”

“Why not.” It wasn’t like I had anything better to do.

Arthur’s hand tightened on the edge of the bar. “Before you say yes. Happens I need more than just an extra gun.”

“I said I’d play it your way, okay? No C-4, roger.” I mock-saluted him.

“Ain’t what I meant. Russell…we ain’t never really talked about this, but…” He’d gone still and tense. “This case, client’s a friend of mine. Real important to me. It’s about her work, and…my friend, she’s a professor.” He wet his lips. “Math professor.”

“No.” The refusal slipped out through stiff lips before I realized I had heard him, and I slid off my stool and stumbled toward the door. The room was whirling a little. I kind of hoped I was just drunker than I thought, but I could do the damn differential equation; I knew I wasn’t.

“Russell, wait.” I felt Arthur catch my arm as my foot missed the ground. “Hey. You okay?”

“Get off.” I tried to shoulder his hand away; the ceiling slipped sideways again.

“You ain’t have to take this job,” Arthur said from somewhere up and to my right. “Forget it. Ain’t no problem.”

At least, that was what his words said. But his voice was tight and desperate, as if the list of people he thought could help his friend began and ended with me.

“Fine,” I ground out. “I’ll help.”

The tension went out of him where he was still touching my arm, and I hated myself. “Sweetheart, I could kiss you,” he said.

“Don’t push your luck.”

Still keeping a supporting hand on my elbow, Arthur pulled out his wallet and threw a handful of bills on the bar. “Come on, let me drive you home. I’ll tell you more on the way.”

“My car is here,” I said.

His eyes slipped back to my seventeen shot glasses lined up in neat groups on the bar. “Ex-cop here. Humor me.”

“I hate cops.”

“Me too.” Something dark flickered in Arthur’s eyes. I’d never found out why he’d left the force, and even I, Queen of Social Disgraces, had eventually clued in I shouldn’t ask about it.

“Fine,” I said. The room was still whirling a little anyway.

Arthur took another glance back toward my neatly grouped glasses as we headed toward the door. “Fibonacci series?”

I looked back at the bar. “Sequence,” I corrected. I hadn’t realized I’d been doing it.

“Like to see the world the way you do some time,” said Arthur.

Vectors stretched out around me in a thousand variations, constantly reforming, lengthening, summing in infinite combinations like I was in the middle of some fucking chess game and couldn’t help but see twenty steps ahead in all directions, and I dearly wished I’d been able to have more alcohol. “No,” I told Arthur. “You wouldn’t.”

Chapter 2

Professor Sonya Halliday,
well-known luminary in the fields of cryptography and complexity theory, greeted us the next morning at the door of her on-campus office. With its sprawling California architecture and palm tree-lined avenues, the university was one of those places that tried so hard to be warm and cheerful that it automatically made me feel rebelliously depressed.

Professor Halliday was a tall, thin African-American woman who was probably in her mid-forties but looked older. She was dressed very precisely in a straight skirt and severe blouse, with her graying hair pulled tightly back from her face. She regarded us through rimless glasses and shook my hand formally when Arthur introduced us. “Are you a private investigator, as well?” she inquired.

“No,” I answered, biting down on the “ma’am” that wanted to pop out afterward. Professor Halliday had that kind of effect. “I do retrieval.”

“I don’t know what that means,” said Halliday, in a tone that demanded I explain.

I resisted the urge to tell her to look up “retrieval” in the dictionary. “It means people hire me to find items of value for them and bring them back safely. Usually things that have been stolen from them.” Usually. Sometimes I was the one doing the stealing. I left that part out.

“Sonya,” said Arthur, his tone much more subdued than I was used to hearing from him, “you said you needed someone who understood the more technical aspects. Cas can do that. Fill her in.”

Halliday turned to look down her nose at him, and the look was all wrong; even I could see that. Arthur had called them good friends, but Halliday was regarding him like he was a bug on a clean tablecloth. “Doubtful,” she said, turning to walk around her desk. She sat down in her office chair and started pulling up files on her computer. I tried to catch Arthur’s eye, but he was steadfastly not looking at me.

“Sonya,” he tried again instead, “I just want to help you, okay?”

She concentrated on her monitor. “I told you to leave me alone.”

“You called
me,”
he pleaded.

“In a moment of weakness. I believe I was very clear I do not want any help from you.”

“Arthur?” I said.

He made a “back off” motion at me with one hand. “You need help. You told me I wouldn’t understand, well, I brought someone who will. Just talk to us. Please.”

“What is your area of specialization?” said Halliday.

She hadn’t looked up, and it took me a second to realize she was talking to me. I wasn’t great at reading people’s tones, but it had never been more obvious someone was trying to set me up to fail.

Oh, fuck you.

I plopped down in one of the chairs across from Halliday’s desk, sprawling in an inelegant slouch. “You know. I do a little of everything.”

“I do not mean to be rude,” said Halliday, “but Arthur does not grasp the level of depth and complexity in my field—”

“Liar,” I said. “You do mean to be rude. Go on, say what you’re thinking.”

She finally turned to regard me, folding her hands on the desk in front of her. “Miss…Miss Russell,” she said, the title only slightly questioning, “I know personally everyone in the same line of research as myself. You must understand how specialized areas of higher math are. Even doctorates in the same general area would require a great deal of study to understand what—”

“I read all the papers you’ve published to date last night,” I said.

She closed her mouth.

“The Internet is a wonderful invention, isn’t it?” I said, deliberately misunderstanding her surprise. “Nice work on the new encryption algorithm using prime roots of unity to approximate randomness. That’s a clever trick.”

Halliday’s voice tightened. “An elementary understanding of—”

“For God’s sake, Sonya,” said Arthur from behind me, low and rough. “You told me you needed someone who understood your work. Let us help you.”

And just like that, Professor Halliday crumpled. Not in a dramatic way—somehow I doubted she did anything dramatically—but her head bowed and her shoulders hunched and she took off her severe rimless specs to press shaking fingers to her face.

Arthur swooped around the desk and put a supportive arm over her thin shoulders. “That’s okay. It’s okay. Just tell us what’s going on.”

Her voice came croakily through her hands. “I think I understand now. What you said about getting in over your head, how easy it was—how you didn’t see what was happening until it was too late.”

Arthur stiffened beside her.

I perked up. “Wait,
Arthur
did something wrong?” Arthur and Halliday both froze, and the room got intensely uncomfortable in a way I tended to find perversely entertaining. “Do tell; I want to hear this.”

“Don’t,” said Arthur, so quietly I almost couldn’t hear the word, his eyes fastened on nothing. He didn’t sound angry—he sounded like he was in pain.

The tension in the room suddenly got a lot less entertaining.

Shit. Way to go, Cas.
I leaned forward and tried to go back to businesslike. “Professor. Arthur told me you had some work stolen. Why don’t you start there.”

Halliday glanced back up at Arthur, who squeezed her shoulders in support and nodded her on. She leaned into him almost imperceptibly. “Not—not some work. All of it.” She’d reached up and was gripping one of Arthur’s hands so tightly the tendons stood out in her wrist. “All my current research. All my notebooks, at home and here at the office—gone.”

Arthur sucked in a breath.

“Okay,” I said. “I take it the police weren’t able to help?”

“I didn’t—” She looked back up at Arthur, and then at me, hesitating.

“I trust Cas with my life,” he said, surprising me.

“I need you to mean that.”

“I promise,” said Arthur. “You can trust her.” Some sort of fuzzy tingly feeling crinkled in my chest at his quiet confidence; I tried not to let it show.

Halliday’s eyes flicked to me, to Arthur, and back. “I might be in—I’m in some trouble. Maybe—a lot of trouble. Arthur…I’m sorry. I’m so sorry.”

“It’s okay,” Arthur said again, almost too firmly. “We’re here to help you. Just tell us what happened.”

She closed her eyes for a long moment, then opened them and focused on me. “I found an efficient integer factorization algorithm.”

I stared at her, the implications crashing through my brain. “You
what?”

“I was only thinking of the math!” She raised a hand as if to excuse or defend herself. “Truthfully, I never let myself believe I would actually solve it. Dwelling on the consequences of a pipe dream—it felt so arrogant, and now…”

“How efficient is it?” I asked. “Even if we’re talking polynomial time, if there’s a large enough constant in there—”

“It’s fast enough,” she said. “I think. The programming part isn’t my area. But it’s fast enough.”

“Shit,” I said, though I couldn’t help the word coming out half-admiring. “Wow.” And then the purpose of our meeting came thundering back. “Wait, someone
stole it from you?
Why the hell are you calling us instead of the police or the FBI or, I don’t know,
anyone?
I’m usually in favor of going outside the law, but when it comes to
wrecking the entire global economy—”

“I know!” cried Halliday. “I know I should have. I tried talking to a friend of mine who works for the NSA—just hypothetically, as if I were considering working on a problem like this, and he told me—” She took a breath, swallowed. “The amount of oversight they wanted if I began work on the problem, the care he told me to take if I was getting close…if they found out I—”

“Yeah,” I said. “Yeah, okay. I get it.” Arthur’s face was a study in confusion; I turned to him and tried to explain. “Pretend you built a nuclear bomb for fun and someone stole it. I don’t know if there’s a law on the books for this, but if they decided they wanted Professor Halliday to go down, they could probably find one. Hell, cryptographic algorithms used to be classified as munitions under U.S. law—a few years ago you could go to jail for sending someone three lines of Perl script. They take this shit seriously.”

“I should have gone to the authorities,” Halliday said. “It was selfish. I was—I confess I was frightened. I have a handful of friends who consult with the NSA, mathematicians, and I could have, I
should
have talked to them right away. And now…now I fear it might be too late.”

“Why do you say that?” said Arthur.

Still gripping his hand with one of hers, Halliday reached down with the other and unlocked a drawer in her desk. She drew out a blue file folder and handed it up to him. “I found this in my office the next day.”

He opened the folder, and his expression twitched, the muscles in his face tightening. He passed the folder to me.

It had one sheet of paper inside. Plain white paper, with plain black lettering printed on it:

“Huh,” I said. “I suppose it could be worse.”

“How?” said Halliday incredulously, some of her control slipping.

“Whoever stole your proof isn’t planning on destroying the world, only being selfish with it—probably getting rich. Unless they feel threatened, apparently. This gives us some time.”

“Time for what?” Halliday demanded. “Whether or not we find who stole it, whether or not we get it back—the information is out there now!”

“
Stop panicking,”
I said. “Or at least go somewhere else to do it after you give us the rest of the information.” I snapped the file folder closed. “We’ll keep this. Now, who else knows anything about the proof?”

“No one,” she said, steadying her voice with an obvious effort. “It was my pet project. My Fermat’s Last Theorem. I was embarrassed even to tell anyone else I was working on it; it seemed too fantastic.”

“You didn’t have any collaborators?”

“No, not on this. Or—only Rita. I talked to her about it sometimes, but I swore her to secrecy. And she didn’t know I had finished.”

“Who’s Rita?” I said.

“You talking about Dr. Martinez?” asked Arthur. “Your doctoral advisor?”

Halliday nodded. “Collaborator now, and we’re very close friends. But she couldn’t be involved.”

“I don’t know,” I said. “Sounds like motive to me, stealing a colleague’s secret proof to publish yourself.”

Halliday snorted. “I would sooner believe Rita capable of murder.”

Arthur and I exchanged a look over her head, but Halliday’s gaze had unfocused into the distance, and she missed it.

“How did the robbery happen?” Arthur prompted gently, after a moment.

“Wednesday I came home and—there was no sign someone had broken in, nothing,” Halliday answered. “But all of my notebooks were gone. Just gone.”

“What about your computer?” I asked.

She shook her head. “I work in longhand. I was only just now going back through the proof to rewrite it for publication—so many years, so many dead ends and notes, and…they took it all. I went back to my office immediately and found my work here cleaned out, too. Even though none of it was relevant to the factorization problem, they still took everything. And the next morning I found the note.”