I'm trying to solve this question:

My attempt of solution:

Note first I use the stereographic projection to see the sphere is homeomorphic to the plane with a point at infinity, after this we get this infinite block with height 1 with a segment of height 1 at infinity.

Am I right? I fell I'm wrong, this space seems very weird.



Just draw a 2-sphere in a 2-sphere and define the space in between to be filled.

  • $\begingroup$ basically it is a 2-dimensional annulus en.wikipedia.org/wiki/Annulus_(mathematics) $\endgroup$ – Daniel Valenzuela Sep 24 '14 at 18:11
  • $\begingroup$ I'm sorry, but Why? $\endgroup$ – user85493 Sep 24 '14 at 18:19
  • $\begingroup$ the "$\times I$" means that you can paramatrize it. So just parametrize it, eg. by saying that the inner sphere is $0$ and the outer sphere is $1$. $\endgroup$ – Daniel Valenzuela Sep 24 '14 at 18:23
  • $\begingroup$ and by this I mean that $X \times I$ is a collection of $(X,t)$ with $t \in I$. $\endgroup$ – Daniel Valenzuela Sep 24 '14 at 18:23
  • 1
    $\begingroup$ yes and you are reminding me that I am really hungry. $\endgroup$ – Daniel Valenzuela Sep 24 '14 at 18:27

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.