[Math] R with usual topology and Z with discrete topology are homeomorphic

compactnessgeneral-topology

I can't decide if the reals with the usual topology is homeomorphic to Z with the discrete topology. I know know that there must be uncountable sets in both topologies because the power set of z has uncountably many sets within itself and there are an uncountable number of reals but this doesn't get me very far. Is this something to do with compactness although I don't know how to use it? Are there standard ways of doing this? An explanation of what's going on here would be appreciated! Thanks

Best Answer

If $(X,\tau_X)$ and $(Y,\tau_Y)$ are homeomorphic, then there is a bijection between the two spaces. Namely, there is a function $f\colon X\to Y$ which is a bijection, and satisfies that $f[U]$ is open if and only if $U$ is open (for $U\subseteq X$).

Now ask yourself, is there a bijection $f\colon\Bbb R\to\Bbb Z$?

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