How can I prove that two sets are isomorphic, short of finding the isomorphism?
I have a set $E \subset X$ within a metric space ($X, d$). I want to prove that it is isomorphic to $\mathbb{R}^{n \times n}$, in the sense that there exists a continuous bijection between the two. Because $E$ is a fairly complicated set, it would be a huge pain to actually find an exact bijection, so instead I hope to identify a sufficient suite of conditions that I can test $E$ for that will suffice to show that the two are isomorphic.
Is there some sort of known method for doing this? Or will I have to find the exact function?
Thanks.
Solution 1:
The necessary and sufficient set of conditions for $E$ to be homeomorphic to $\mathbb R^{m}$ (in your situation $m=n^2$):
- $E$ must be a topological manifold of dimension $m$
- $E$ must be contractible
- $E$ must be simply connected at infinity
More details here.