Are These Metric Spaces Topologically Equivalent but Not Both Complete?

  • Thread starter Thread starter zilla
  • Start date Start date
  • Tags Tags
    Metric
zilla
Messages
7
Reaction score
0

Homework Statement


Give an example of two metric spaces (X1, d1) and (X2, d2) which are topologically equivalent and for which (X1, d1) is complete and (X2, d2) is not.


2. The attempt at a solution
The open unit disc and R2. They are homeomorphic, but there are Cauchy sequences in the disc which will converge to limits outside of the disc, so it's not complete.
 
Physics news on Phys.org
I can't argue with your reasoning.
 
Thanks - I was pretty sure, but wanted to check.
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
Back
Top