# Topology Question...

• Oct 25th 2009, 08:08 AM
TTB
Topology Question...
Hi guys,

I really need help with the following question:

Let A be the infinite countable union of circles with radius 1/n & centres (1/n,0) in Euclidean 2-space. ie - subspace

Let B be the infinite countable union of circles with radius n & centres (n,0) in Euclidean 2-space. e - subspace

Let C be the wedge of countably many circles.

1) Which of these 3 spaces are CW complexes?

2) Attempt to construct contiinuous bijectiive maps between these spaces (if possible) & then show if these are homeomorphisms.

3) Are the any other more "immediate" way of showing any of the spaces are homeomorphic?

I'm completely stuck! :-( Any assistance would be ENORMOUSLY helpful!

• Oct 25th 2009, 08:09 AM
TTB
PS - the instructor hinted that A is not homeomorphic to B or C - but I have no idea how to show this! :-s :-(

Thanks x
• Oct 25th 2009, 04:13 PM
aliceinwonderland
Quote:

Originally Posted by TTB
Hi guys,

I really need help with the following question:

Let A be the infinite countable union of circles with radius 1/n & centres (1/n,0) in Euclidean 2-space. ie - subspace

Let B be the infinite countable union of circles with radius n & centres (n,0) in Euclidean 2-space. e - subspace

Let C be the wedge of countably many circles.

1) Which of these 3 spaces are CW complexes?

2) Attempt to construct contiinuous bijectiive maps between these spaces (if possible) & then show if these are homeomorphisms.

3) Are the any other more "immediate" way of showing any of the spaces are homeomorphic?

I'm completely stuck! :-( Any assistance would be ENORMOUSLY helpful!