Finite Covers of the Infinite Cyclic Cover of a Knot
نویسنده
چکیده
We show that the commutator subgroup G ′ of a classical knot group G need not have subgroups of every finite index, but it will if G ′ has a surjective homomorphism to the integers and we give an exact criterion for that to happen. We also give an example of a smoothly knotted S n in S n+2 for all n ≥ 2 whose infinite cyclic cover is not simply connected but has no proper finite covers.
منابع مشابه
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