Water bowline the working end around the standing line and back through both half hitches. This is illustrated in the three pictures below. Water bowline The water bowline is a type of knot designed for use in wet conditions where other knots may slip or jam. Although similar in finished appearance to the double bowline, the water bowline is formed with a clove hitch as the loop in the standing part of the rope. This is similar to the double bowline, which puts the running end through a round turn. The additional friction from the clove hitch increases the security of this
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