So quick, normally, to make up his mind, Dyer cannot decide. The friend of the missing Australian mathematician had given the letter that he had received posthumously from him to the police. Obviously, the thing for Dyer to do, sipping his tea, was to get this post-it note to Lionel Updark. That was the first path he should take.

But the prospect of handing over Marvar’s information to Updark makes Dyer dizzy, disoriented. The fact that Updark socialised with Cubbage, and was supposed to be at the dinner party with him, puts Dyer off, given all that he has heard from Lorna about the Americans.

He stares again at what Marvar has written, and feels that he is being sucked backward in the current. These numbers and letters – like some abracadabra. E = mc2 gave us the atom bomb. But Marvar’s calculations? Is it possible to read too much into them? Could they be nothing more than clotted bilge, like Todd Angle’s bushwhacked philosophy – or one of Dyer’s maths preps for Slimy? ‘This is fit only,’ Slimy had said, ‘for toilet paper.’

7, M, Q fus, nTτ … The muddle of figures, like the mistakes that the typesetters used to make. Dyer is tempted to view the whole thing as gobbledygook.

What he has been searching for is a simple algorithm for how to live. What did he want the world to think of him, who did he love best in it? His life was a coded set of letters and figures awaiting a solution.

Dyer thought back, as people in a crisis do, to where he had come from. A large part of him, too much, went back to Astrud.

He saw her sometimes in another, crossing a chequered floor to touch a shoulder, her eyes, the stubborn curl over her left ear that she was always brushing down. The bar is full, the book is open on the table with a fresh pencil mark in the margin. ‘What are you reading?’

And afterwards, the empty mornings and afternoons. In the evenings he sits at a table with a glass of cold beer and a book, watching the faces. A samba is playing. His face is wet. They were supposed to be his great days.

Vivien had tried to comfort him. Following the funeral at Nossa Senhora da Candelária in Petrópolis – Astrud in the coffin, the hands that had touched his shoulder – his aunt rang every week, compelling him to talk. ‘It’s bad to remember, but it’s worse not to.’

He had thrown his door keys at the doctor who brought him the news. In the sunlight of his first day of mourning, he was tearing at his own fur. He cut his hair. He couldn’t listen to music, read a book, eat moqueca.

After she died, her dog didn’t go into their room.