The Conway Polynomial (or Alexander-Conway polynomial) Δ_{L}(z) of an oriented
knot or link L is given by det(z^{1/2}A - z^{-1/2}A^{t}), where A is a
Seifert matrix for L.

It can be shown that the Conway Polynomial is determined by the following skein relations:

(1) Δ_{Unknot}(z) = 1

(2) Δ_{L+}(z) - Δ_{L-}(z) = zΔ_{L0}(z),

where L_{+}, L_{-}, and L_{0} are three oriented links which are
the same except in a neighborhood of a point where they differ as in the figure below.

[1] Lickorish, W. B. R., *An introduction to knot theory*. New York: Springer (1997).

[2] Image taken from *Wikipedia, * Alexander Polynomial.