Yosemite bowline knot. A stopper knot, while serving to keep the loose end tidy, will not only help to prevent failure of the primary knot, but also act as a secondary safety knot itself. It is sometimes said that if enough of a tail is left to tie a stopper knot, the stopper becomes unnecessary. The tail should be a minimum of 40–60 cm depending on the thickness of the rope. Yosemite bowline A Yosemite bowline is loop knot often perceived as having better security than a bowline. It has been pointed out that if the knot is not dressed correctly it
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