Can an uncountable subset of $\mathbb{R}$ have empty intersection with its derived set?
324
Show uncountable set of real numbers has a point of accumulation
145471
$\Gamma \subset \mathbb{R}^{+}$ is uncountable. Can we choose a sequence from $\Gamma$ of which the sum is $\infty$
86685
Example of a set $S$ that is countable, but the set of limit points is uncountable
47251
Non-compactness of $\mathbb{R}$ with the cocountable topology
70543
Does an uncountable discrete subspace of the reals exist?
22391
Is the set of all pairs of real numbers uncountable?
83842
Alternate proofs (other than diagonalization and topological nested sets) for uncountability of the reals?
19754
$\mathbb{R}$ \ $\mathbb{Q}$ and $\mathbb{R}^2\setminus\mathbb{Q}^2$ disconnected?
39020
Why is empty set an open set?
106455
intersection of infinite collection of finite sets?
58285
Is it true that if $X$ is connected, then for every nonempty proper subset $A$ of $X$, we have $\mathbf{Bd} \ne \emptyset$
7607
How to prove that $\mathbb{Q}$ is not the intersection of a countable collection of open sets.
88205
How can I define a topology on the empty set?
53429
In a complete metric space with no isolated points, any countable intersection of open dense sets is uncountable?
132692
Nonempty set mapped to $\emptyset$ and vice-versa
80827
Let $A$ be a nonempty subset of $\mathbb{R}$. Prove...
18527
Confusion on Derived Sets and the $n$-the Derived Set