Bowline on a bight end(s) and tucking the bight back down beside itself. Instead, the bight is opened up to allow the whole knot to pass through it (see picture on right). When tightened, the bight now embraces the pair of standing ends (see top picture) Bowline on a bight The Bowline on a bight is a knot which makes a pair of fixed-size loops in the middle of a rope. Its advantage is that it is reasonably easy to untie after being exposed to a strain. This knot can replace the figure-eight knot when tying into a climbing harness. However, it is critical
Arf invariant of a knot slice knot is a square integer. As formula_12 is an odd integer, it has to be congruent to 1 modulo 8. Combined with Murasugi's result this shows that the Arf invariant of a slice knot vanishes. Arf invariant of a knot In the mathematical field of knot theory, the Arf invariant of a knot, named after Cahit Arf, is a knot invariant obtained from a quadratic form associated to a Seifert surface. If "F" is a Seifert surface of a knot, then the homology group H("F", Z/2Z) has a quadratic form whose value is the number of full twists mod