Alexander polynomials are classical invariants in knot theory and have been extensively studied.

The Alexander polynomial of a link in a rational homology sphere can be defined in the powerful and very appropriate context of Reidemeister torsion theory as a Reidemeister torsion of the exterior X of the link (up to a well-determined factor for a knot) and, following [Tu], it can be given a suitable sign, and hence a suitable normalization, if X is equipped with an orientation of

The normalization of this Alexander polynomial for oriented links in S^{3}was frrst pointed out by Conway and