Knot theory exercise sheet - week V (1) Determine the colouring ...
Knot theory exercise sheet - week V (1) Determine the colouring ...
Knot theory exercise sheet - week V (1) Determine the colouring ...
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<strong>Knot</strong> <strong><strong>the</strong>ory</strong> <strong>exercise</strong> <strong>sheet</strong> - <strong>week</strong> V<br />
(1) <strong>Determine</strong> <strong>the</strong> <strong>colouring</strong> group for any 4 non-trivial knots from<br />
<strong>the</strong> table.<br />
(2) <strong>Determine</strong> <strong>the</strong> <strong>colouring</strong> group for <strong>the</strong> Hopf link, Whitehead<br />
link and <strong>the</strong> Borromean rings. What is <strong>the</strong> determinant of<br />
<strong>the</strong>se links?<br />
(3) <strong>Determine</strong> <strong>the</strong> <strong>colouring</strong> group of <strong>the</strong> following knot<br />
Can you identify this knot in <strong>the</strong> table of knots? What is<br />
<strong>the</strong> determinant of this knot?<br />
(4) Give an example of a knot or a link with <strong>the</strong> <strong>colouring</strong> group<br />
isomorphic to:<br />
(a) Z<br />
(b) Z 2<br />
(c) Z n<br />
(d) Z/3<br />
(e) Z/5<br />
(f) Z/7<br />
(g) Z/p, where p is a prime number.<br />
(h) Z/3 ⊕ Z/5<br />
(i) Z/15<br />
(j) Z/2<br />
(5) Calculate <strong>the</strong> Alexander polynomial for <strong>the</strong> figure eight knot, a<br />
knot with 7, 8 and 9 crossings and for <strong>the</strong> knots 3 1, 5 1, 7 1<br />
and 9 1.<br />
(6) <strong>Determine</strong> <strong>the</strong> Alexander polynomial for <strong>the</strong> Borromean rings.<br />
1
2<br />
(7) Is <strong>the</strong> following link splitable?<br />
(8) Express <strong>the</strong> following knot as <strong>the</strong> sum of prime knots and determine<br />
its Alexander polynomial.<br />
(9) Suppose that <strong>the</strong> polynomial t 4 +5t 3 +5t 2 +5t+5 is <strong>the</strong> Alexander<br />
polynomial of a knot K. Is K prime?