Tom fool's knot Tom fool's knot The Tom fool's knot is sometimes considered a handcuff knot but is somewhat inferior for this purpose to the knot which usually bears that name. It is a good knot with which to commence a slightly fancy sheepshank. It is also used as a trick knot due to the speed with which it can be made. Tom fool's knot is believed to be the knot "epankylotos brokhos" described by the 1st Century Greek physician Heraklas. It is formed by making two loops, not exactly overlaying each other. The inner half of each hitch or loop is pulled
Arf invariant of a knot slice knot is a square integer. As formula_12 is an odd integer, it has to be congruent to 1 modulo 8. Combined with Murasugi's result this shows that the Arf invariant of a slice knot vanishes. 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