- Knot polynomial
In the mathematical field of
knot theory , a knot polynomial is aknot invariant in the form of apolynomial whose coefficients encode some of the properties of a given knot.History
The first knot polynomial, the
Alexander polynomial , was introduced byJ. W. Alexander in 1923, but other knot polynomials were not found until almost 60 years later.In the 1960s, John Conway came up with a
skein relation for a version of the Alexander polynomial, usually referred to as theAlexander-Conway polynomial . The significance of this skein relation was not realized until the early 1980s, whenVaughan Jones discovered theJones polynomial . This led to the discovery of more knot polynomials, such as the so-calledHOMFLY polynomial .Soon after Jones' discovery,
Louis Kauffman noticed the Jones polynomial could be computed by means of astate-sum model , which involved thebracket polynomial , an invariant of framed knots. This opened up avenues of research linking knot theory andstatistical mechanics .In the late 1980s, two related breakthroughs were made.
Edward Witten demonstrated that the Jones polynomial, and similar Jones-type invariants, had an interpretation inChern-Simons theory .Viktor Vassiliev andMikhail Goussarov started the theory offinite type invariant s of knots. The coefficients of the previously named polynomials are known to be of finite type (after perhaps a suitable "change of variables").In recent years, the Alexander polynomial has been shown to be related to
Floer homology . The graded Euler characteristic of the knot Floer homology of Oszvath and Szabo is the Alexander polynomial.References
*Colin Adams, "The Knot Book", American Mathematical Society, ISBN 0-8050-7380-9
*W. B. R. Lickorish , "An introduction to knot theory." Graduate Texts in Mathematics, 175. Springer-Verlag, New York, 1997. ISBN 0-387-98254-Xee also
Specific knot polynomials
*
Alexander polynomial
*Bracket polynomial
*HOMFLY polynomial
*Jones polynomial
*Kauffman polynomial Related topics
*
skein relationship for a formal definition of the Alexander polynomial, with a worked-out example.
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