Unfaithful - Natalie Barelli Page 0,5

feel excited by the possibility but feeling devastated instead. Finally, I looked up. He was grinning, and I wanted him to go away. I wanted to say I had work to do, that I had no time for this.

Then he said it.

“The Pentti-Stone conjecture. I think I have an angle.”

He looked nervous, almost frightened.

“Really?”

“Yes.”

There’s a prize too: $500,000 to the first person to prove or disprove the Pentti-Stone. Not as much as mathematics’ Millennium Prize—that’s the big one, at $1,000,000—but not small change, either.

I stood up to close the door, even though the room felt airless. “You want to talk me through it?”

He did, animatedly, chaotically and yet beautifully. He hadn’t come up with a complete solution yet, but the work he’d done on his thesis to date had accidentally nudged him in the right direction.

“I think I can do it,” he said, breathless.

I paused, willing my heart to slow down. “It’s harder than you think.”

“I know. I need your help, Anna. Will you help me?”

Would I help him? My first thought was no. Absolutely not. But how could I say no? What if he found another supervisor? Someone at MIT maybe? Could I bear it? And if I said yes, I could think of it as closing a circle. The end of the work I’d started so very long ago.

“And I want to change my PhD topic to this,” he continued. “Can I do that?”

I thought about it. The ramifications were negligible; people changed their topic all the time.

“And it has to remain secret,” he added. “For obvious reasons.”

“Obviously.” If it became known at this point, even just within the university, that Alex was close to solving the Pentti-Stone, and especially what his approach was, there was no doubt someone else would jump on it and quite possibly snatch the prize before he did. Us academics might look mild-mannered and geeky on the surface, but underneath we’re a bunch of hyenas who’d do anything for a scrap of recognition.

“Not even your husband,” he said.

“Honestly, Alex, Luis wouldn’t know the Pentti-Stone from the Rosetta Stone.”

“I don’t care. Nobody can know, you have to swear. Nobody.”

I did. I swore. I’m good at keeping secrets, I said. I was already thinking of what it might mean for the university, the research funding we’d be able to attract. This would be a game changer for our faculty. We would join the ranks of the most prestigious academic institutions in America.

After that, the conjecture was all he could think about, but passion has its consequences: he lost weight, lost sleep, grew dark circles under his eyes.

We spent months on it, which is not very long in the scheme of things. People spend years, decades, trying to solve a conjecture. He went down rabbit holes a few times. He’d think he was so close, then one detail would make the whole thing crash and he’d have to start again.

Then he became paranoid that people were spying on his work. He wouldn’t put anything at all in a computer in case we got hacked. He wrote everything by hand and kept it in a locked drawer in my desk, even though he had his own locked cabinet in an office he shared with other students.

“I don’t trust them,” he said.

“So, lock it in your cabinet then.”

“Anna, they’re on wheels!”

In the end we agreed he could work in my office, which I would lock whenever I was out. I also had a small desk brought in especially for him. It was kind of exhilarating because we made progress so quickly. But when his health deteriorated, when he couldn’t cope with the pressure, he was awful to be around. I dreaded coming to work. He was always angry, sad, desperate. Manic. Then he became resentful of me because he thought I wasn’t doing enough to help him. As if somehow it was my fault he hadn’t solved it yet. Like it was simple multiplication and I hadn’t explained to him how to do it.

Then he stopped coming altogether. I knew he wasn’t working on it at home because all his notes were in my office. Then one night I woke up in the middle of a dream with an idea. I tiptoed downstairs and called him. I told him my theory. What if…? What do you think? Would that work? Two days later he’d cracked it.

A PhD thesis can only be authored by the student in question. But we agreed to write a paper together about the Pentti-Stone