[FOM] Removing Deep Pathology 1
Colin McLarty
colin.mclarty at case.edu
Fri Aug 21 07:25:12 EDT 2015
The circles of the Hopf fibration are just topologically circles, while I
think those intended by the example
> 4) The partition of 3-space by (infinitely long) non-parallel lines.
> 4a) " " " " " non-parallel circles.
are metric circles. Anyway the fibers of the Hopf fibration do not lie in
non-parallel planes, since they do not lie in planes at all.
More to Harvey's point, while the Hopf fibration had a surprising
consequence in topology (non-triviality of higher homotopy of spheres), it
is not pathological in any logical sense. It is explicitly definable by
degree 4 polynomials.
Colin
On Thu, Aug 20, 2015 at 4:36 PM, Hendrik Boom <hendrik at topoi.pooq.com>
wrote:
> On Thu, Aug 20, 2015 at 12:36:45AM +1200, W.Taylor at math.canterbury.ac.nz
> wrote:
> >
> > >just what does nonparallel mean for circles?
> >
> > Lying within non-parallel planes.
>
> My spatial visualisation is challenged here, but with this definition,
> it's possible that the Hopf fibration satisfies the nonparallel
> constraint. Anyone know for sure?
>
> It does have one straight line -- that's the circle of infinite radius
> I mentioned. Perhaps that's a deal-breaker.
>
> -- hendrik.
> _______________________________________________
> FOM mailing list
> FOM at cs.nyu.edu
> http://www.cs.nyu.edu/mailman/listinfo/fom
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: </pipermail/fom/attachments/20150821/553c9794/attachment.html>
More information about the FOM
mailing list