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Aste T., Weaire D. Pursuit of perfect packing (IOP 2000)(147s).pdf

Aste T., Weaire D. Pursuit of perfect packing (IOP 2000)(147s).pdf

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36 Pro<strong>of</strong> positive<br />

from sophistication to more elementary methods was one secret <strong>of</strong> his success.<br />

Nevertheless his preprint ran to about 100 pages and was not easily digested even<br />

by those hungry for information. As his colleagues and competitors picked over<br />

the details, some errors became apparent.<br />

This is not unusual. Another recent claim, <strong>of</strong> an even more dramatic result—<br />

the pro<strong>of</strong> <strong>of</strong> Fermat’s Last Theorem—has required some running repairs, but is<br />

still considered roadworthy and indeed prizeworthy. However, Hsiang did not<br />

immediately succeed in rehabilitating his paper.<br />

Exchanges with his critics failed to reach a resolution. A broadside was<br />

eventually launched at Hsiang by Thomas Hales in the pages <strong>of</strong> the splendidly<br />

entertaining Mathematical Intelligencer. Hales’ piece lies at the serious end <strong>of</strong><br />

that excellent magazine’s spectrum but nevertheless it grips the reader with its<br />

layers <strong>of</strong> implication and irony, most unusual in a debate on a piece <strong>of</strong> inscrutable<br />

academic reasoning.<br />

Despite the inclusion <strong>of</strong> some conciliatory gestures (‘promising programme’,<br />

‘improves the method’) the overall effect is that <strong>of</strong> a Gatling gun, apparently puncturing<br />

the supposed pro<strong>of</strong> in many places. Hales begins with the statement that<br />

‘many <strong>of</strong> the experts in the field have come to the conclusion that [Hsiang’s]<br />

work does not merit serious consideration’ and ends with a demand that the claim<br />

should be withdrawn: ‘Mathematicians can easily spot the difference between<br />

hand-waving and pro<strong>of</strong>’.<br />

Hsiang replied at length in the same magazine, protesting against the use <strong>of</strong> a<br />

‘fake counter example’. Meanwhile Hales and others were themselves engaged in<br />

defining programmes for further work, as the explorer stocks supplies and makes<br />

sketch-maps for a hopeful expedition. Indeed he was already at base camp.<br />

A comment by Kantor on Hilbert’s 18th problem<br />

Hilbert’s text gives the impression that he did not anticipate the<br />

success and the developments this problem would have.<br />

The hexagonal <strong>packing</strong> in plane is the densest (pro<strong>of</strong> by Thue<br />

in 1892, completed by Fejes in 1940). In space, the problem<br />

is still not solved. Although there is very recent progress by<br />

Hales. For spheres whose centres lie on a lattice, the problem<br />

is solved in up to eight dimensions. The subject has various<br />

ramifications: applications to the geometry <strong>of</strong> numbers, deep<br />

relations between coding theory and sphere-<strong>packing</strong> theory, the<br />

very rich geometry <strong>of</strong> the densest known lattices. (Kantor J M<br />

1996 Math. Intelligencer Winter, p 27)

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