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In the early 1980's Mike Freedman showed that all
knots with trivial Alexander polynomial are topologically slice (with
fundamental group Z). This paper contains the first new
examples of topologically slice knots. In fact, we give a sufficient
homological condition under which a knot is slice with
fundamental group Z semi-direct product Z[1/2]. These
two fundamental groups are known to be the only solvable
ribbon groups. Our homological condition implies that the
Alexander polynomial equals (t-2)(t-1-2) but also contains
information about the metabelian cover of the knot complement (since
there are many non-slice knots with this Alexander polynomial).
Note
Example 1.5 is incorrect, for a correct example
see the Erratum.
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