Figure-eight knot (mathematics)

Figure-eight knot
Common name	Figure-eight knot
Arf invariant	1
Braid length	4
Braid no.	3
Bridge no.	2
Crosscap no.	2
Crossing no.	4
Genus	1
Hyperbolic volume	2.02988
Stick no.	7
Unknotting no.	1
Conway notation	[22]
A–B notation	41
Dowker notation	4, 6, 8, 2
Last / Next	31 / 51
Other
alternating, hyperbolic, fibered, prime, fully amphichiral, twist

In knot theory, a figure-eight knot (also called Listing's knot^[1]) is the unique knot with a crossing number of four. This makes it the knot with the third-smallest possible crossing number, after the unknot and the trefoil knot. The figure-eight knot is a prime knot.