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Sossinsky:Knots. Mathematics with a twist.pdf - English

Sossinsky:Knots. Mathematics with a twist.pdf - English

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10 KNOTS<br />

here are a few remarks on their "wild" kin (<strong>with</strong> a few drawings in­<br />

cluded).<br />

Digression: Wild <strong>Knots</strong>, Spatiallntuition, and Blindness<br />

The examples of wild knots shown up to now possess a single isolated<br />

pathoIogicaI point, toward which a succession of smaIler and smaIler<br />

knots converge. Wild knots <strong>with</strong> severai points of the same type can<br />

easily be constructed. But one can go further: Figure 1.9 shows a wild<br />

knot that has an infinite (even uncountabIe, for those who know the<br />

expression) set of pathoIogicaI points.<br />

This set of wild points is in fact the famous Cantor continuum, the<br />

set of points in the segment [O, 1] that remain after one successiveIy<br />

eliminates the centraI subintervai (1/3, 2/3), then the (smaller) centraI<br />

subintervais (1/9, 2/9) and (7/9, 8/9) of the two remaining segments,<br />

O .l l.<br />

9 9<br />

.l<br />

3<br />

l.<br />

3<br />

L<br />

9<br />

.a<br />

9<br />

-=== == == =: :.- -=::: :I I •<br />

Figure 1.9. A wild knot converging to Cantor's continuum.

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