Triple bowline Triple bowline The triple bowline knot is a variation of the bowline knot. The knot can be applied to emergency situations, such as mountain rescue. The name comes from the three loops that would be formed by tying this knot. The knot is tied in the same way the original bowline is, except with a doubled rope (using a bight). An overhand loop is formed in the rope, the working end is passed back through that loop, behind the standing part of the rope, back through the loop and pulled tight. The working end (bight) forms a third loop, often
Arf invariant of a knot the knot, constructed from a set of curves on a Seifert surface of genus "g" which represent a basis for the first homology of the surface. This means that "V" is a 2"g" × 2"g" matrix with the property that "V" − "V" is a symplectic matrix. The "Arf invariant" of the knot is the residue of Specifically, if formula_3, is a symplectic basis for the intersection form on the Seifert surface, then where formula_5 denotes the positive pushoff of "a". This approach to the Arf invariant is due to Louis Kauffman. We define two knots to be pass equivalent