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 graph associated to a knot diagram. This approach to the Arf invariant is by Raymond Robertello. Let be the Alexander polynomial of the knot. Then the Arf invariant is the residue of modulo 2, where "r" = 0 for "n" odd, and "r" = 1 for "n" even. Kunio Murasugi proved that the Arf invariant is zero if and only if Δ(−1) formula_8 ±1 modulo 8. From the Fox-Milnor criterion, which tells us that the Alexander polynomial of a slice knot formula_9 factors as formula_10 for some polynomial formula_11 with integer coefficients, we know that the determinant formula_12 of a