$\omega$ covers and Lindelöf property
67279
Is the union of finitely many open sets in an omega-cover contained within some member of the cover?
119624
A Dedekind infinite set has a countably infinite proper subset
73154
Compact subset in colimit of spaces
66895
A condition for the image of a metrizable space to be metrizable
30587
Uncountable well ordered set in $Z^-$ theory.
148927
Why does every countable limit ordinal have cofinality $\omega$?
10702
Show that $\left\{A\subset\Omega: A~\text{ is countable or }A^C\text{ is countable}\right\}$ is a $\sigma$-algebra
95234
Quasi-components in compact space
128334
Question regarding open covers in Zariski topology (distinguished opens of affine schemes are quasi-compact)
93621
Prove that $\mathbb{Z}[\omega]$ is an integral domain
65196
Gluing Lemma for Closed Sets: Infinite Cover Counter-Example
127622
Does there exist a $1$-form $\alpha$ with $d\alpha = \omega$?
56143
Proof of a basic $AC_\omega$ equivalence
88598
Property of $\{0^n, 1^n, \ldots\}$
106534
"Closed subsets of compact space are compact" with an alternative definition of covering
59850
If $f$,$g$ and $\overline{f}g$ are holomorphic on $\Omega$, then $g=0$ or $f$ is constant
25498
Prove that $\omega + \omega_1 = \omega \cdot \omega_1 = \omega^{\omega_1} = \omega_1$