X uncountable implies X' uncountable
99854
Must an uncountable subset of R have uncountably many accumulation points?
58471
Accumulation points of uncountable sets
140799
Prove that there exist uncountable family of subsets of $\mathbb{N}$ which is linearly (totally) ordered by relation of inclusion.
86685
Example of a set $S$ that is countable, but the set of limit points is uncountable
80019
$\varepsilon$-number countability without choice
67064
Uncountable minus countable set is uncountable
99064
Uncountable set with exactly one limit point
146006
Uncountable $\sigma$-algebra
19297
Is the cofinite topology on an uncountable set first countable?
9021
An infinite subset of a countable set is countable
72750
Uncountable number of mutually disjoint countable sets in $\mathbb R$
38726
What set theory axioms do I need to believe in uncountable ordinals?
63678
Let $A$ and $B$ be countable sets. Is there any function $f$ such that a certain condition holds for an uncountable number of functions $g$?
88904
Help with a proof. Countable sets.
130981
Co-countable measure on uncountable set
93389
Uncountable sets of Hausdorff dimension zero
17733
$X$ second countable locally compact Hausdorff implies $C(X)$ separable?