Let $X$ be the subset of $\mathbb{R}^2$ given by the union of
- the unit circle
- the $y$-axis
- all lines through the origin with rational slopes
equipped with the subspace topology. Is there a simple characterization of $\pi_1(X)$?
Let $X$ be the subset of $\mathbb{R}^2$ given by the union of
equipped with the subspace topology. Is there a simple characterization of $\pi_1(X)$?
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