A set dense in $L^2(\mathbb{R})$
61539
proof for a basis in $L^2$
84686
Geometric Description Of a Set In The Complex Plane
116806
Find the weak sequential closure of a set in $L^2(-\pi,\pi)$
65963
Dense sets in Hilbert space of square summable sequences?
122463
How to show the that a set $A$ nowhere dense is equivalent to the complement of $A$ containing a dense open set?
90826
Constructing a subset not in $\mathcal{B}(\mathbb{R})$ explicitly
135441
When is $\mathbb{Z}[\alpha]$ dense in $\mathbb{C}$?
28391
Prove the compactness of a set B
47975
Closed cone in the euclidean space $\mathbb{R}^n$
121831
Proving that rational numbers are dense
102250
Subset of $C[0,1]$ is nowhere dense
3023
Construction of a Borel set with positive but not full measure in each interval
4381
Proof that the set of irrational numbers is dense in reals
115272
Showing that projections $\mathbb{R}^2 \to \mathbb{R}$ are not closed
30568
Let $q \in \mathbb C$, $\|q\|=1$ and $q^n \neq 1, \forall n \in \mathbb N$. Show that $\{q^n: n \in \mathbb N\}$ is dense in $S^1$
85870
Show this set is a base for some topology on $\mathbb{Z}$
68490
For $x\in\mathbb R\setminus\mathbb Q$, the set $\{nx-\lfloor nx\rfloor: n\in \mathbb{N}\}$ is dense on $[0,1)$