Definition:Ordinal Space/Closed/Countable

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Let $\Gamma$ be a limit ordinal.

Let $\Omega$ denote the first uncountable ordinal.

The countable closed ordinal space on $\Gamma$ is a particular case of an closed ordinal space $\closedint 0 \Gamma$ where $\Gamma < \Omega$.

That is, it is the set $\closedint 0 \Gamma$ of all ordinal numbers less than or equal to $\Gamma < \Omega$, together with the order topology.

Also see

  • Results about ordinal spaces can be found here.