(−2,3,7) pretzel knot

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(−2,3,7) pretzel knot
Pretzel knot.svg
Arf invariant 0
Crosscap no. 2
Crossing no. 12
Hyperbolic volume 2.828122088
Unknotting no. 5
Conway notation [7;-2 1;2]
Dowker notation 4, 8, -16, 2, -18, -20, -22, -24, -6, -10, -12, -14
D-T name 12n242
Last /Next 12n241 12n243 
Other
hyperbolic, fibered, pretzel, reversible

In geometric topology, a branch of mathematics, the (−2, 3, 7) pretzel knot, sometimes called the Fintushel–Stern knot, is an important example of a pretzel knot which exhibits various interesting phenomena under three-dimensional and four-dimensional surgery constructions.

Mathematical properties[edit]

The (−2, 3, 7) pretzel knot has 7 exceptional slopes, Dehn surgery slopes which give non-hyperbolic 3-manifolds. The only other hyperbolic knot with 7 or more is the figure-eight knot, which has 10. All other hyperbolic knots are conjectured to have at most 6 exceptional slopes.

A pretzel (−2,3,7) pretzel knot.

Further reading[edit]

  • Kirby, R., (1978). "Problems in low dimensional topology", Proceedings of Symposia in Pure Math., volume 32, 272-312. (see problem 1.77, due to Gordon, for exceptional slopes)

External links[edit]