Can iterated arithmetical operators break closure over $\mathbb C$?
50314
Can tetration 'escape' the complex plane?
148507
Why an open set in $R^n$ might not be written as countable union of disjoint open intervals?
72420
Is $\mathbb{N}$ impossible to pin down?
44361
An automorphism that has no fixed points except for the identity and is its own inverse implies commutativity
43584
Separability and normal closure
88028
Topology - closures of intervals with the order topology
108740
$C^1[a,b]$ is closed in $C[a,b]$
90475
Coordinate-free proof of $\operatorname{Tr}(AB)=\operatorname{Tr}(BA)$?
133266
If $(X, \mathcal{T})$ has a countable subbasis, then it has a countable basis
107842
Behaviour of ($\overline{a}_n)_{n=1}^{\infty}$ and ($\underline{a}_n)_{n=1}^{\infty}$
150605
Existence of a regular uncountable $\aleph_{\alpha}$ without $\mathsf{AC}$
35868
Elementary properties of closure
143586
Is $[0,1]$ a union of family of disjoint closed intervals?
25874
Showing that a certain map is not flat by explicit counterexample
152193
The intersection of a closure with an open set
108930
Show that an operation being commutative is a structural property
142093
The closure of an irreducible subset of an irreducible space is irreducible.