Karash double loop harness. The traditional method of tying this knot starts with a reverse loop (like the Eskimo bowline) then wraps around the standing end (AKA the "tree"), you then finish the knot the same way as the BOAB – Bowline on a bight. An alternative way as advertised by the French Federation of Speleology and Mike Karash is starting with a figure of eight on a bight, then pulls two strands of the rope back through the bight. Karash double loop Karash double loop is a common name for a knot forming two loops. This knot has been a known variant
Arf invariant of a knot 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 2 in a neighborhood of an imbedded circle representing an element of the homology group. The Arf invariant of this quadratic form is the Arf invariant of the knot. Let formula_1 be a Seifert matrix of