aU = rU

c

Do you disagree?'

Möbius had looked at the thing scrawled on the screen of Harry's mind. The age of the universe is equal to its radius divided by the speed of light. And after a moment, but very quietly now: Yes, I agree.

'Hah!' said Harry. 'It's hard to get a decent argument going these days. Everyone cries uncle.'

Möbius had been angry. He had never seen Harry like this before. Certainly the Necroscope's instinctive maths was a wonderful thing, an awesome talent in its own right, but where was Harry's humility? What on earth had got into him? Perhaps Möbius should let him continue to expound and then try to pick holes, bring him down a peg or two.

And time? And the multiverses?

But Harry had been ready for him: 'The space-time universe - which has the same size and age as any and all of the parallels - is cone-shaped, the point of the cone being the Big Bang/Primal Light where time began, and the base being its current boundary or diameter. Is that feasible, logical?'

Desperately seeking errors, still Möbius had been unable to discover them. Yes, he was obliged to answer, eventually. Feasible, logical, but not necessarily correct.

'Grant me feasible,' said Harry. 'And then tell me: what lies outside the cone?'

Nothing, since the universe is contained within it.

'Wrong! The parallels are cone-shaped, too, born at the same time and expanding from the same source!'

Möbius had pictured it. But... then each cone is in contact with a number of other cones. Is there evidence of this?

'Black holes,' said Harry at once, 'which juggle with matter and so perform a necessary balancing act. They suck matter out of universes which are too heavy, into universes which are too light. White holes are, of course, the other ends of the black holes. In space-time such holes are the lines of contact between cones, but in space they are simply - ' (a shrug,) ' - holes.'

Möbius was tired, but: Cones are circular in cross-section, he'd argued. Put three together and you get a triangular shape between them.

And Harry had nodded his agreement. 'Grey holes. There's one at the bottom of the Perchorsk ravine, and another up an underground river in Romania.'

And so he'd made his point and won his argument, if there had been one to win in the first place. For the fact was he'd only argued for the sake of it and neither knew nor cared if he was right or wrong.

But Möbius had cared, because he didn't know if Harry was right or wrong either...

Another time, the Necroscope had talked to Pythagoras. Again his principal reason for going to see him was to convey his thanks (the great Greek mystic and mathematician had been of some assistance in his quest for numeracy), but again the visit had ended in argument.

Harry had thought to find the Greek's grave at Metapontum, or if not there then at Crotona in southern Italy. But all he found was a follower or two until, by pure chance, he stumbled upon the forgotten, 2,480-year-old tomb of a member of the Pythagorean Brotherhood on the Island of Chios. There was no marker; it was a stony, ochre place where goats ate thistles not fifty yards from a rocky shore looking north on the Aegean.

Pythagoras? No, not here, that one informed, in a hushed and very secretive manner, when Harry's dead-speak broke into his centuried thoughts. He is elsewhere, waiting out his time.

'His time?'

Until his metempsychosis, into a living, breathing man!

'But do you converse? Are you able to contact him?'

He will occasionally contact us, when a thought has occurred to him.

'Us?'

The Brotherhood! But I have said too much. Begone. Leave me in peace.

'As you wish,' Harry had told him. 'But he won't thank you that you turned away the Necroscope.'

What? The Necroscope? (Astonishment, and awe.) You are that one, who taught the dead to speak out in their graves, so enabling them to talk to one another as in life?

'The same.'

And do you seek to learn from Pythagoras?

'I seek to instruct him.'

That is a blasphemy!

'Blasphemy?' Harry had raised an eyebrow. 'And is Pythagoras a god, then? If so, a painfully slow one! Consider this: I have already achieved my metempsychosis. Even now I embark upon a second phase, a new... condition.'

Your soul is in process of migration?

'I may say that a change is in the offing, certainly.'

And after a while: If I speak to our master Pythagoras on your behalf, and if you have lied to me, be sure he willdamn you with Numbers. Aye, and possibly me with you! No, I dare not. First prove yourself.

'Perhaps I can show you some numbers.' Harry had contained his impatience as best he could. 'As a member of the Brotherhood, I'm sure you will appreciate their importance.'

Do you seek to seduce me with your puny figures? What, the work of a mere lifetime? Are you suggesting that in the two thousand years and more which have passed since I was lain to rest here I've dreamed no numbers or equations or formulae of my own? Necroscope or none, you are presumptuous!

'Presumptuous?' Harry's anger had been aroused. 'Equations? Formulae? Why, I have formulae such as you could never dream.' And he'd displayed the computer screen of his mind, and covered it with the endlessly mutating algebraics of Möbius mathematics. Then he'd formed a Möbius door, and let the other gaze a moment upon the nowhere and everywhere across the threshold.

Until, gaspingly: What... what is that?!

The Big Zero,' Harry had growled then, letting the door close on itself. The place where all numbers begin. But I'm wasting my time. I came to talk to a master and ended up chatting with a mere student - and a middling one at that. Now tell me: do I get my audience with Pythagoras or don't I?'

He ... he is in Samos.

'Where he was born?'

The same. The last place anyone would think to look for him, he thought... And then, frantically: Necroscope -plead with him for me! I have betrayed him! He will exclude me!

'Rubbish!' Harry had growled, but without scorn. 'Exclude you? He will elevate you - for you have gazed upon the secret mathematical door to all times and places.

You don't believe me?' (And he'd shrugged). 'Well, it's your choice. My thanks anyway - and farewell.' And conjuring another Möbius door he'd stepped through it -

- And out again on Samos, twenty miles away, where Pythagoras had spent his childhood two and a half millennia ago, and to which his bones had been returned in secrecy when at last he died. Pythagoras, however introvert, secretive, diffident, could hardly escape or ignore the Necroscope's deadspeak probe at such close range. That thought in itself had been deadspeak and as such the recluse (in death even more than in life) had heard it. And answered: What is your number?

'Any you choose for me,' Harry had shrugged, homing in on the mystic's mental whisper. And when he'd located him definitely, one further Möbius jump took him from a deserted, wooded shoreline straight there: to a small olive grove on a terraced hillside above a headland with a tiny white church. Down the coast a little way, scarcely glimpsed through pines and wind-warped oaks, Tigani's harbour glinted turquoise, blue, silver; music from a taverna came drifting on the bright summer air.

It was cool in the shade of the trees and the Necroscope had been grateful to take off his wide-brimmed hat, also the dark-lensed spectacles which protected his now delicate eyes. And because Pythagoras had remained silently thoughtful: There are numbers galore. I'm not fussy.'