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Sep 21, 2018 at 5:57 vote accept Dominic van der Zypen
Sep 20, 2018 at 20:15 answer added KP Hart timeline score: 7
Sep 20, 2018 at 20:00 comment added Will Brian @JamesHanson: That's correct. (You can prove it via transfinite induction. I don't have a reference, but I encourage you to give it a try -- it's a good exercise.)
Sep 20, 2018 at 19:34 comment added James E Hanson I'm fairly sure every countable ordinal can be embedded in $\mathbb{R}$.
Sep 20, 2018 at 19:06 comment added Dominic van der Zypen Good question @JamesHanson. Even if we take everyone's darling space $\mathbb{R}$ with the Euclidean topology, I think it is not hard to see that $\omega \cdot \omega$ can be embedded into $\mathbb{R}$, but I am not sure about larger limit ordinals. So I do not know the smallest ordinal that cannot be embedded into $\mathbb{R}$ even. But this is certainly known, I'll try and Google it
Sep 20, 2018 at 17:14 comment added James E Hanson Do you know if every countable ordinal embeds into every non-trivial connected $T_2$ space?
Sep 20, 2018 at 15:52 history edited Dominic van der Zypen CC BY-SA 4.0
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Sep 20, 2018 at 15:24 history asked Dominic van der Zypen CC BY-SA 4.0