Triple bowline a "seat" in which the injured person can be raised or lowered safely. The full triple bowline is also used in rescue situations with the third loop passed around the waist or torso. The triple bowline is often mistakenly referred to as the double bowline. The double bowline is in fact a bowline tied on a single strand with the nipping loop doubled up, and only has one loop. 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
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