'Your father - my son - was one of the two best probability mathematicians the galaxy has ever seen. You have found out about probability maths, I gather. It's been around for about five hundred years. John refined it. He postulated the Pothole Effect, and when that was proved, p-math went from a toy to a tool. We could take a minute section of the continuum - a human being, for example - and predict its future in this universe.

'John did this for you. You were the first person ever quantified in this way. It took him seven months, and how we wish we knew how he managed it, because even the Bank can't quantify a person in less than a year with any degree of accuracy. Your father had genius, at least when it came to p-math. He ... wasn't quite so good at human relationships, though.

She shot an interrogative glance at Dom, but he did not rise to the bait. She went on: 'He was killed in the marshes, you know.'

'I know.'

John Sabalos looked out over the sparkling marshes, towards the distant tower. It was a fine day. He surveyed his emotions analytically, and realized he felt content. He smiled to himself, and drew another memory cube towards him and slotted it in the recorder.

'And therefore,' he said, 'I will make this final prediction concerning my future son. He will die on his half-year birthday, as the long year is measured on Widdershins, which will be the day he is invested as Planetary Chairman. The means: some form of energy discharge.'

He switched off for a few seconds while he collected his thoughts, and then began: 'The assassin: I cannot tell. Don't think I haven't tried to find out. All I can see is a gap in the flow of the equations, a gap, maybe, in the shape of a man. If so, he is a man around whom the continuum flows like water round a rock. I know that he will escape. I can sense him outlined by your actions like - damn, another simile - a vacuum made of shadow. I think he works for the Joker Institute, and they are making a desperate attempt to kill my son.'