Zimmerman's Algorithm

2.04 Wed. Mar. 18

AFTER meeting Julia's parents, Gideon rented a room at a motel and slept for nearly twelve hours. At eight the next morning he drove back into the Zimmermans' Brooklyn neighborhood and drove up to Madison High School. It was an imposing pile of brick looming over the street. He parked in front of it for a long time, wondering what he was doing here. Whatever had happened to Julia here was ancient history—

He was supposedly looking for what had happened to him, his brother— not what had happened to Julia Zimmerman.

What he needed to know was why this woman needed a stolen supercomputer, and why the government was going to extreme lengths to stop her.

In the end, it was Julia Zimmerman—as much as the faux Secret Servicemen, as much as Lionel—who was responsible for Rafe's death. Gideon told himself that that was the reason he was here, unearthing her history. Julia was central to what was going on.

She was certainly central now to his investigation.

Gideon needed to know what drove her, to know what thoughts moved behind her enigmatic gray eyes.

He turned off the engine and entered the school armed with a crutch and his badge.

Gideon walked into an empty classroom. A green metal desk presided over ranks of tan desks. The ceiling was high, and a trio of windows let in the morning light. Lining the rear wall was a long table with a half-dozen computers. Green blackboards flanked three walls, one marked up and labeled, "Do Not Erase," it was a list of problems for calculus homework. The symbols looked somewhat familiar.

"Problem #8: Test to decide the convergence or divergence of the following infinite series.

After talking to two mathematicians already, Gideon felt he could almost understand the notation. It was very similar to the Zeta function, another infinite series of additions. Gideon tapped his finger next to the "°°," thinking of that other infinity, the one Julia used for the Evolutionary Theorems Lab, the one on the business card, "No."

"Can I help you?" came a voice from behind him.

Gideon turned and saw a thin, white-haired man carrying a stack of papers that seemed wider than he was.

"Mr. Sandier?" Gideon asked, turning around to face the man.

The man nodded as he emptied his papers onto his desk. "And you are?"

Gideon extended his hand. "Gideon Malcolm. I'm a detective with the Washington D.C. Police Department. I wanted to ask you about one of your former students."

Sandier didn't take Gideon's hand, making an attempt to appear as if he hadn't seen the gesture. "A little out of your jurisdiction, Detective Malcolm, aren't you?"

"I'm investigating the background of a crime that happened in the District."

Sandier looked at Gideon's crutch and up at his face. "Do I know you?"

"If you could give me a few minutes."

Sandier looked at the pile of papers in front of him. "Only a few minutes. I have papers to grade, and it's only . an hour before my first class."

Gideon nodded.

Sandier pulled out a red pencil and pulled the top paper from off the stack in front of him and began checking pages of handwritten equations.

"Do you remember a student named Julia Zimmerman?"

The red pencil stopped, leaving an unfinished red mark on the paper under Sandler's hand. "Yes," he said. "Some students aren't easily forgotten."

"What kind of student was she?"

Sandier looked up, "The worst kind, Mr. Malcolm. Intelligence with no respect behind it. Disruptive. Mocking. That's what kind of student she was."

"Mocking?"

Sandier returned to checking his paper. "She was mocking just by being in my class. I teach an honors class in Calculus, the highest level of mathematics offered in this district. It is a serious subject that should be treated seriously. I've taught this class for twenty-five years, and there is no place for girls like her here."

"Girls like her?"

"Questioning the authority of her instructor, making him look foolish in front of his students . . ."

"What did she do?"

Sandier lowered his pencil and looked up at Gideon. "Zimmerman was bored by school. Those types, most of them, they just stop coming to class. Occasionally they do the work, hand it in, but they're otherwise absent. Those types don't make it to my honors class. She was different. She came, every day, and held everyone responsible for her own boredom." Sandier shook his head. "She was ruthless with errors. It didn't matter whose. Anyone could be writing an equation on the board—I have the students do it with the homework problems— and sooner or later there would be a soft sigh from Zimmerman's desk, she'd shake her head and resume reading whatever it was she was really interested in . . ."

Sandier didn't admit it, but Gideon was certain that he'd been on the receiving end of that sigh.

"She was always right about it. The problems were wrong. The few times I asked her what she found wrong, she could recite the whole problem and identify at least three obvious errors without looking at any notes or the blackboard." Sandier looked back down at the paper he was grading. "She resented this class. She never took notes, paid no attention to the lectures, and spent the class period reading books that had nothing to do with what we were supposed to be studying."

"She didn't do the work?"

"She had a five-subject, college-ruled notebook. In the first week of class she filled that book with every study question in the textbook. Whenever I'd assign homework after that, she'd find the page in that notebook, tear it out, and hand it in after class. She was arrogant, aloof, and I had to get special permission to test her out of my class."

Gideon stood there, looking at the ranks of desks, picturing a young Julia Zimmerman feeling trapped in a class that was far beneath her ability. Again, he wondered what he was doing here. Still, he asked, "What kind of books did she read?"

"What?" Sandier asked.

"The books she read in class, the ones that had nothing to do with what you were studying."

"It was a long time ago, I don't remember the titles."

Gideon was certain he was lying. However, he didn't press the point because he wasn't sure what he was trying to discover here. "What kind of person was she? Did she have a lot of friends?"

"Friends? Not from this class. She intimidated people, they kept their distance."

And in return she savaged anyone who made a mistake. A little revenge for being so isolated. Gideon wondered why she came to the class at all. Sandier was right. A lot of kids like that—smart enough to be bored with their classes—he knew ones like them, often ended up fading out of class entirely.

What was your home like, Julia?

What was your life like?

A black Lincoln Town Car idled two blocks away from Madison High School. Two men waited inside the vehicle. Both wore charcoal-gray business suits. The driver wore a crimson tie, the passenger's was

black. They were splitting a bag of McDonald's takeout between them.

The driver sipped a cup of coffee while the passenger peered through a thin pair of binoculars at the Nissan parked in front of the high school.

"What's he doing here, Nev?"

Nev rummaged in the bag between their seats, his hand emerging with a single french fry. He ate it without moving the binoculars. "It isn't our job to figure that out."

"This wasn't on the list of the Doctor's probable contacts."

Nev loosened his tie, letting his collar open on a deep bruise that graced his neck. "We're assigned to this guy because he might come across something no one else has."

A lone black figure, leaning on a single crutch, hobbled out of the main entrance of the high school. Nev lowered his binoculars and said, "There he is."

As he watched Gideon Malcolm move toward his car, he reached for a cell phone and dialed a long string of numbers. He held it up while it rang a few times. When he heard someone answer, he said, "Hello, Mom? Me and Sammy are still with Uncle here. We're at another store and we still don't have the cake mix you wanted." Nev looked up at the high school. "I wanted to know if we should stay with Uncle, or if we should keep looking here."

A male voice on the other end said, "You stay with Uncle, I'll send one of your brothers to look at that store."

Nev nodded and hung up. He gestured toward Gideon, who was just getting into his car. "Mom says we stay with Uncle."

The driver, whose name wasn't Sammy, nodded and pulled out into the street a few moments after Gideon did.

Gideon tracked Ruth Zimmerman to a studio apartment in Greenwich Village. Driving through Manhattan was a nightmare, and every other car seemed to be a taxi bent on killing him. He didn't reach the village until nearly eleven and it was halfway to noon'before he found the street she was supposed to live on.

Gideon wasn't a New Yorker, but he had thought he could navigate in Manhattan well enough. After all, the whole island was laid out in a grid. Unfortunately, someone forgot to mention that fact to the Village, which had some of the most twisted and confusing streets he'd seen this side of Boston.

Gideon found the building after about a half hour of searching. It was a set of apartments above a gay bookstore, a coffee shop, and an Asian store with a large bronze Buddha sitting in the window. The apartments above were hidden by plastic sheets and scaffolding. Gideon couldn't tell if they were restoring the building or tearing it apart. He spent the remaining half hour before noon looking for a parking spot within a reasonable distance of the place.

He didn't know if he had any chance of catching her at home during the day, but he had already decided that he had the time to wait for her if she was at work or school. The worst part of it was the two-block walk back to the building after he parked his car. His leg had been feeling better, a bit stronger, so he'd left the crutch. Halfway there he realized that was a mistake, but he was too stubborn to go back and get it. Instead, he stopped at the coffee shop on the ground floor of Ruth Zimmerman's building, sat down, and ordered an expresso.

Gideon sat at a table with the coffee and tried to get a handle on what was going on.

What he had was a maladjusted teenager who grew up to be a mathematical genius. Resistant to authority. Prone to work alone, with her own priorities and her own agenda. Not someone Gideon would've pegged for government work. Julia Zimmerman seemed way too independent minded.

As he sat there, he thought about Kendal. He frowned at his coffee.

Kendal had found out about Zimmerman independently. He said she was working for a group called the International Unification Front. That was almost as hard to believe as Zimmerman working for the NSA.

I should be spending my time investigating the IUF, not Zimmerman. Why am I here?

It was his fault Kendal was shot, and it seemed more and more that all this was an exercise in avoiding responsibility for his brother.

"No, something is rotten here," Gideon whispered. He knew, and Kendal knew. Right after Kendal was shot, his last words were about a setup. . .

"Blackmail. Theft. Setup. Bait."

What had he been saying?

What’s the sequence of events here? Zimmerman's working for the NSA doing God-knows-what with

higher mathematics and computers. Around New Year's she bolts, apparently granting her services to the IUF. After that, Colonel Ramon and company swipe a Daedalus. Michael Gribaldi hires the late Davy Jones to boost a truck to transport the stolen computer. Davy tells Lionel about the score, and Lionel rats him out. Ramon and his people are captured with the Daedalus in tow, and the Feds bury the capture so they can set up an ambush at the meeting place. Somehow Davy gets called off the job while Gideon and Rafe walk into a covert antiterrorist military unit that's pretending to be Secret Service.

Lionel, Davy, and Kendal all wind up dead, Congress tries to hide the investigation from the media, and the grand jury decides not to ask any difficult questions.

"Wonder if I missed anything," Gideon muttered as he frowned at his coffee.

With it all laid out in his head like that, it brought one major question to light. Who tipped off Davy—and presumably the IUF—that the Daedalus pickup was going to be an ambush?

"Fuck," Gideon said to himself. He was out of his depth here.

There were two types of cops in the world. The first one was the type who got their badge, and did their best to do absolutely nothing for the next twenty years. God forbid they bust someone and have to go appear in court. The second one was obsessed with the bad guys, taking down any scum that's responsible for the evil that he sees on the street every day. The first type are the ones who end up becoming corrupt; the second type are the ones that stress out and go nuts.

Gideon knew what type he was. Couldn't run away. Couldn't ignore it. No matter how outclassed he might be. And while Doctor Zimmerman seemed to be the linchpin to what happened, he couldn't leave her alone.

The coffee was empty. He set it down and left to see if Ruth Zimmerman was home.

As he walked into the apartment's entryway, a black Lincoln Town Car drove by the street outside.

At the end of a narrow hallway stood a large door. It was covered with sheet metal and painted black. Layers of old paint gave the door its own rough topography. The apartment number, "2," was stenciled on the door in yellow paint. Gideon stood in front of Ruth's door to catch his breath after climbing two flights of stairs.

Next to the door, set in the wall, was a little thumb-turn device that operated the doorbell. Gideon turned it, and felt the resistance of an old clockwork mechanism as the bell rang. For a while there was no answer, then a trap door fell away from a peephole that was drilled in the metal door. Gideon could see a single green eye look at him.

"What? Who're you?"

"My name's Gideon Malcolm, I'm a—"

"What do you want?"

"—detective with the Washington D.C. Police Department."

"Really?" Gideon saw the eye scan him up and down through the hole. "Let me see some ID."

Gideon took out his shield and opened the case in front of the peephole. "Left, so I can read."

He shifted it to the left.

"My left, your right."

He shifted it back.

'That isn't an NYPD badge."

"I said I was from Washington D.C."

"Yeah, what're you doing here?"

"I want to ask you some questions about your sister."

"Been there, done that." The door on the peephole shut the eye out.

"Shit," Gideon muttered to himself. He bent over and rang the bell again, twisting the thing several times in a row. "Ruth Zimmerman," he called to the door, "I need to talk to you."

After a moment, the peephole opened and Ruth said, "Go away. Can't you take a hint? Get a warrant."

"I'm not working with the Feds. I'm here on my own."

"Are you trying to impress me?"

"I'm trying to find out why my brother was killed."

There was a bit of a pause. Then Ruth asked, "What was your name again?"

"Gideon Malcolm."

The peephole door shut again. Gideon sighed and was about to lean on the doorbell again when the door opened a couple of inches. It slid to the side and stopped short on a chain.

"Come over where I can see you," Ruth said.

Gideon stepped over into the sliver of light that the open door let into the hallway. While Ruth looked him over, he took the opportunity to size her up.

She hadn't inherited her sister's height. She was about a head shorter than Gideon. She had curly hair that was cut short, and Gideon could see traces of paint on it. In fact, there was paint everywhere. There was a smear of yellow on her cheek, violets and indigos stained her hands, and the overalls she wore were a patchwork of browns, whites, and reds. Paint even stained the old copy of USA Today she held in her hands.

She turned it around, and Gideon saw a perfectly clean circle surrounded by a sharp ring of spattered blue paint, as if a paint can was sitting on the paper until just recently.

"That's you?" Ruth asked. "Isn't it?"

Gideon recognized the picture, him on his doorstep cursing the reporters. Looking at it, he was almost embarrassed to admit it, but he nodded.

"You're the cop the Secret Service shot up." She looked him up and down. "You heal quick."

"Not as quick as I'd like. Can I please talk to you?"

"What's Julie have to do with this?" She waved the paper. "Or you?"

"I think that ambush was meant for your sister."

Ruth stared at him. "That? Her? But why, she works for the government—" She shook her head and muttered, "Julie, you arrogant bitch!"

"What is it?" Gideon asked.

Ruth kept shaking her head, then she closed the door.

Gideon heard the chain rattle, then the door opened again, all the way. Ruth had crumpled up the old newspaper and tossed it on the floor. She waved him into the apartment. "Come on. Have a seat if you can find one."

Gideon walked into the apartment and Ruth slid the door shut behind him.

"This isn't a great place to talk right now, wait here." She left him standing in the entryway.

Gideon took a few steps into the apartment. It was a huge studio loft. Right now it was lit by plastic-filtered sunlight, the scaffolding outside cutting the light into abstract shadows.

Most of the room was empty, all the furniture had been pushed into one corner and covered with a large sheet of canvas. Cans of paint were scattered about, sitting on sheets of newspapers. There were at least five ladders of various sizes leaning up against the walls. The walls by the pile of covered furniture—about a quarter of the room—were still covered with old whitewash peeling off the red brick. Another quarter of the room had the whitewash stripped off the brick. The rest was a mural in progress. The painting was all a single scene, as if Gideon was looking out at an ocean sunset from some small atoll. He could see the surf crashing on the rocks near the floor, he could follow the waves, getting smaller and smaller until they reached a waist-high horizon, then the walls became a sky riotous with color. The depth was amazing, down to the sparkling reflection on the waves.

Gideon stared at the mural and wondered if this wasn't a "great place" to talk because she was in the middle of this work, or for some more sinister reason. After what had happened so far, it was easy to believe that Dr. Zimmerman's sister would be watched by someone.

Ruth appeared from behind a set of screens opposite the pile of covered furniture. The overalls were replaced by jeans, a black turtleneck, and a black motorcycle jacket. She put on a pair of sunglasses as she walked toward him. "Come on, let's go get some lunch," she said.

She still had traces of paint in her hair and on her hands.

Gideon followed her down the steps, straining to keep up with her. She didn't slow down for him, didn't much seem to notice him. She turned away from the coffee shop and crossed the street and stepped inside an Indian restaurant. The restaurant was a few steps below street level, and it took a few moments for Gideon to get down the stairs. He was grateful when a woman with a sari led the two of them to a booth. The place was about half full, a large proportion of the lunchtime crowd wearing business suits and power ties.

Ruth stared across at Gideon, and he wished she'd take off the sunglasses so he could read her expression. When the waitress came with the menus, Ruth ordered something unpronounceable with lamb in it, Gideon ordered the same thing, even though he wasn't sure what it was.

When the waitress left, Gideon leaned over and asked, "Can we talk about your sister?"

Ruth kept looking at him, the sunglasses hiding her expression. "What's she done? You tell me."

"I don't know, other than she's disappeared. From the look of her house, it was a well-planned disappearance."

"Left without a two-week notice, I bet."

Gideon nodded, "If her history at MIT is any indication, she left with more than that."

Ruth lowered her sunglasses and stared at him over the frames. "You know about that?"

"I've talked to some people in Cambridge."

Ruth nodded.

The waitress brought over a couple of glasses of water. Gideon took a sip and rubbed the ache in his wounded leg. "She seems to be very possessive about her work."

Ruth laughed. She raised a hand to stifle herself and started shaking her head. "You can't own the sacred mysteries."

"What?"

"I don't think you understand Julie."

"I'm trying to."

"You've got to picture our family—"

"I've met them already."

Ruth nodded. "Then you've seen it."

"Seen what?" That your mother's gone off the deep end?

"They've done everything except change their name."

Gideon shook his head. "I don't understand."

Ruth took off the sunglasses and set them on the table. "No, I guess you wouldn't. I suppose it's hard for someone to pretend they aren't black."

"You'd be surprised."

"What it is, I think, what happened to me and my sister. Is that our folks decided to stop being Jewish. They just stopped sometime before Julie was born. Didn't move, or change their name, but between the two of them they just let the tradition lapse."

"What? Did they convert?"

Ruth laughed again. "No, that would require thought, planning. They didn't make a decision, they just stopped working at it. Laziness and disinterest more than anything else."

"And this helps explain Dr. Zimmerman's behavior?"

"You need to understand that before you can understand her—or me for that matter." She drank from her glass and set it down. "Do you know where atheists come from?"

"Huh?"

"Passionate atheists almost always come from religious families. You have to know something before you reject it."

"But you're not an atheist?"

Ruth shook her head. "In college I tried being a pagan, but I really couldn't find the belief in me. Me and Julie were left without a heritage, our folks just left a void in our lives and both of us tried to fill it as best we could. I'm still trying. I've made friends with a Reform rabbi and I'm trying to make up for some of what I've lost. You know the closest I've been to a seder until last year was watching The Ten Commandments."

"How did Julia fill that void?"

"She took a page from the ancient Greeks."

"What? She believes in Zeus?"

Ruth shook her head, but this time she didn't laugh. She looked at him with an expression of grave seriousness. "No, Pythagoras."

The New Pythagoreans, Gideon thought. He remembered all the papers he had copied from MIT. What Dr. Nolan said, about the people at the ET Lab believing in her work started to take on a whole new connotation.

Dr Cho had said, "Some might call mathematics a religion . . ."

The waitress brought their food, and while they ate, Ruth told him about Julia Zimmerman.

A long time ago, before Julia went off to college in California, Ruth had asked her if she had believed in God.

"God?" Julia had said. Julia had been rummaging in her dresser while her younger sister sat on the edge of her bed, feet dangling, barely touching the ground. Julia stopped what she was doing, leaned back on the dresser, and looked down at her sister. The expression on her face was deep, as if she was looking past Ruth, or into her. "I can tell you about the time I first knew that there was a God."

It had been in the fifth grade, when she had a class with Mrs. Waxman. She was the youngest child in

the class, having already skipped a grade. By then her ability with mathematics was already beginning to flower. She played with numbers more than she did with other children. She had already discovered esoteric operations that her classmates didn't know existed. While they were just starting to reach for fractions, she had touched upon squares, logarithms, roots, and was just making tentative steps into trigonometry.

She'd do the multiplication drills with everyone else, and when she was done, she would spend the rest of the time doodling magic squares on the back of the papers.

Mrs. Waxman never liked her. She was convinced that somehow Julia was cheating. She would call Julia to the board repeatedly to try and catch her in some error.

Julia hated Mrs. Waxman.

Then, near the end of the school year, Julia's resentment at her teacher boiled over when she was convinced she'd caught her teacher in an obvious mistake. Mrs. Waxman was at the board, talking about the number line;

-2-1012

Mrs. Waxman marked off the whole numbers on the line and stated that the number line went off to infinity in both directions. That made perfect sense to Julia. She already understood enough about the integers, she had a clear image of the whole numbers marching off to infinity.

Then Mrs. Waxman said that there were an infinity of fractions on the number line, as many fractions as there were whole numbers. She divided up the number line. Again Julia understood, while it took Mrs. Waxman a while to convince her classmates. Between any two whole numbers, there were as many fractions as there were whole numbers. While her teacher droned on, Julia had amused herself by mentally constructing a proof. It took her a moment, but she soon could line up every possible fraction with a sequence of whole numbers. She could picture an infinite matrix, numerators changing by rows, denominators by columns . . .

Then, while Julia was thinking through her proof, Mrs. Waxman made her mistake. She said that, in fact, there were as many numbers between zero and one as there were whole numbers.

Julia had to speak up at that. She said it didn't make sense, that Mrs. Waxman had to be wrong. Mrs. Waxman, at first, was relieved at the outburst. For once Julia had shown what Mrs. Waxman thought was a flash of mathematical ignorance. Her response to Julia's assertion was to reassure the entire class that the space between zero and one could be divided into an infinite number of points, as could any segment on the number line.

Julia was frustrated with Mrs. Waxman's blindness. She said again that she was obviously wrong with what she was saying. Of course she could put an infinity of points on the line, that wasn't the problem.

Mrs. Waxman was dumbfounded for a few long moments.

Julia carefully started to explain that there had to be more points between zero and one than there were whole numbers. However you would try to count those points, there would be an infinity of numbers that would fall into each of the holes between the numbers you did manage to count.

Mrs. Waxman asserted that an infinity was an infinity. Julia kept insisting she was wrong, in front of the whole class. Infuriated, Mrs. Waxman sent her to the principal, and the principal sent her home with a note to her parents telling them that Julia was disruptive in class and talked back to the teacher.

Her father wouldn't hear any explanations from Julia. He just strapped her with his belt and sent her to her room for four days.

During that exile, she read Men of Mathematics, a book by E.T. Bell. Near the end she discovered the chapter on George Cantor and his discovery of transfinite numbers. She discovered the symbol, " N."

"It was like a sign," Julia had told her sister, "A revelation. Until then I had trusted other people, adults, to tell me what truth was. I didn't need faith in them anymore. I knew that there was another truth, eternal, unchanging, and immune from Mrs. Waxman's assertions."

"But what about God?" Ruth had asked her.

"God is there," Julia said. "He is in the equations. His truth is decipherable to anyone who can reason far enough. God is a Theorem. Someday He will be proved."

The story fit seamlessly into what Gideon knew about Julia Zimmerman. It even explained the symbol she used, " N." Though the Baptist in him was having trouble with "God is a Theorem."

"What did she mean by that?" Gideon asked her.

Ruth set down her fork and asked, "What's the point of spirituality, Detective Malcolm?"

The air in the restaurant was suddenly dark and very still. Gideon lowered his own fork and looked into

Ruth's eyes. He felt a vague embarrassment at not being more religious himself. He'd been raised Baptist by his father, but he hadn't been to church in ages. Before he'd been shot, he hadn't talked to God in years. Here was someone who was raised in a spiritual vacuum, and who seemed to've put more thought into the subject during one conversation with her sister than he had for most of his life.

"I guess the point of it is to give us a meaning, a direction in life. Some sense of right and wrong. . ."

"A reassurance that there's something else," Ruth said. She knocked gently on the table. "Something beyond this somewhat disappointing world we find ourselves in. Something better, purer, more right, more real."

Gideon nodded.

"It seems to be human nature from ancient times to believe that this world is but a pale reflection of a perfect, incorruptible realm. Plato said it was all shadows on the wall of a cave. The Greek geometers believed that literally everything had emerged from the sequence of natural numbers."

"So what does Julia believe?"

"She believes that mathematics is the only way we can see clearly into that perfect, incorruptible realm. She believes that any truth that it uncovers is a window into the mind of God."

Gideon felt unconvinced. "But we're talking about something invented by man. How can that bear any relation to God? Even in somebody's mind?"

"It's self-reinforcing. You can see echoes of mathematical behavior in everything from a fall of a stone to a nautilus shell. Julia believed that everything discovered by mathematics had some reflection in the physical world."

Gideon nodded. "Did this have any relationship with the work she did at MIT?"

"We didn't talk much after she went off to college. Only a few times while she was at MIT."

"Dr. Nolan—he worked with her in the lab—said she was beginning to act as if the programs they were creating were living creatures . . ."

"Computers always fascinated her." Ruth looked up at Gideon and watched him carefully. "Why are you here? You're out of your jurisdiction, and you're asking me questions that can't have any bearing on what happened."

"I don't know what has a bearing, and what doesn't. Would her fascination with computers lead to her wanting the use of a Daedalus?"

"I thought they had one where she works—worked."

Gideon leaned back and thought. Of course Julia would have access to the NSA's Daedalus. What would she be doing that needed it? And why would she leave when she already had access . . . ?

"Julia went off on her own tangents a lot, didn't she?"

"What do you mean?"

"The stories I hear about her, writing her own notebooks during calculus class, writing magic squares on her test papers. It sounds as if she was the type of person who would do her own private research on the side."

Ruth narrowed her eyes at him, as if he was unearthing something she hadn't thought about. "What do you mean? She never said anything like that to me."

"Think for a moment. The Evolutionary Theorems Lab published a lot of material, a lot of people did their own research there. When she left, though, she wiped all the computers. It was as if she was hiding her work, but most of the work—up to the whole Riemann business—was already public. Why get into a possible legal struggle with the university?"

"I always thought that she was trying to get back at MIT for shutting her lab down."

"Does that seem like her to you?"

"What do you mean?"

"You know her better. All I know is what people have told me. But she doesn't seem like a particularly vengeful person."

Ruth looked across the table at Gideon, shaking her head. "Losing the lab was a big blow to her."

"But it was out of character, wasn't it? She's the type that would let a wrong slide by and be satisfied she was right—I mean, when Waxman reprimanded her, Julia looked up George Cantor and found out she was right all along."

"Yes."

"Did she ever show Waxman that book? Your father?"

Ruth leaned back. "No, at least she never said she did. But she was just a kid then."

"The child who'd grow into the kind of person to strike out at an employer out of spite would make every effort to prove Mrs. Waxman wrong, preferably in front of the whole class."

"But she wiped the computers. Out of character or not."

Gideon nodded. "When people do something out of character, nine times out of ten, they're hiding something."

"Like what?"

"Like her own private research. If she was doing something on her own, she might not have wanted MIT to have it. If that's the case, I'd wonder if she continued that work with the government's equipment." "Like what?"

"Something she needs a Daedalus for."