Questions tagged [retraction]

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Is it okay to do that with proving $\mathbb R^2$ and $\mathbb R^2 \setminus \left\{0\right\}$ are homeomorphic?

We want to show $\mathbb R^2 \setminus \left\{0\right\}$ and $\mathbb R^2$ are homeomorphic (Goal), but I already proved that $\mathbb R^2 \setminus \left\{0\right\}$ and $S^1$ are homeomorphic. And I already proved that $S^1$ and $B^2$ are not…
girrafe
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