I glanced at her warily. She was smiling. She turned to me, all hostilities momentarily forgotten, and whispered, “He’s wrong! He thinks he’s found a way to discard the isolated-point topologies; he’s cooked up an isomorphism which maps them all into a set of measure zero. But he’s using the wrong measure . In this context, he has to use Perrini’s, not Saupe’s! How could he have missed that?”

I had only the vaguest idea of what she was talking about. Isolated-point topologies were “spaces” where nothing actually touched anything else. A “measure” was a kind of generalization of length, like a higher-dimensional area or volume – only they included much wilder abstractions than that. When you summed something over all the topologies, you multiplied each contribution to the infinite sum by a “measure” of “how big” the topology was … a bit like weighting the worldwide average of some statistic according to the population of each country – or according to its land area, or its Gross Domestic Product, or some other measure of its relative significance.

Buzzo believed he’d found a way of tackling the calculation of any real physical quantity which made the effective contribution of all the universes of isolated points equal to zero.

Mosala believed he was mistaken.

I said, “So, you’ll confront him when he’s finished?”

She turned back to the proceedings, smiling to herself. “Let’s wait and see. I don’t want to embarrass him. And someone else is sure to spot the error.”

Question time arrived. I strained my limited grasp of the subject, trying to decide if any of the issues raised were Mosala’s in disguise – but I thought not. When the session ended and she still hadn’t spoken, I asked point blank: “Why didn’t you tell him?”

She became irritated. “ I could be mistaken. I’ll have to give it more thought. It’s not a trivial question; he may have had a good reason for the choice he made.”

I said, “This was a prelude to his paper on Sunday week, wasn’t it? Clearing the ground for his masterpiece?” Buzzo, Mosala and Yasuko Nishide were scheduled to present their rival TOEs – in strict alphabetical order – on the last day of the conference.

“That’s right.”

“So … if he’s wrong about the choice of measure, he could end up falling flat on his face?”

Mosala gave me a long, hard look. I wondered if I’d finally managed to push the decision out of my hands: if she’d withdraw her cooperation entirely, leaving me with no subject to film, no reason to remain.