# What knot groups are Abelian?

The knot group (the fundamental group of the complement of a knot) of the unknot is $\mathbb{Z}$ and the Hopf link is $\mathbb{Z}^2$, so those are knots (links) with Abelian knot group but are there any more?

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At least for a knot, what would that say about the Wirtinger representation of the knot group? –  Neal Mar 19 '12 at 14:51