“…In [13], Hayden presents a certain pair of slice disks
and
for
, each with complement having fundamental group
. By a result of Conway–Powell [
6, Theorem 1.2], this implies that
and
are topologically isotopic. However, in [13, section 2.1], it is shown that
and
are not smoothly isotopic (or even diffeomorphic) rel boundary.…”