The Alexander polynomial as a universal invariant

Let \mathsf{B}_1 be the polynomial ring \mathbb{C}[a^{\pm1},b] with the structure of a complex Hopf algebra induced from its interpretation as the algebra of regular functions on the affine linear algebraic group of complex invertible upper triangular 2-by-2 matrices of the form \left( \begin{smallmatrix} a&b\\0&1 \end{smallmatrix}\right). We prove that the universal... Show more