Dense convex proper subset of the Hilbert space $l_2$: $\{x|\sum x_i=0\}$
12212
Showing a certain subspace of Hilbert space is dense
50160
The quotient norm on $\ell^{\infty}(\mathbb{N}) / c_0 (\mathbb{N})$ is given by $\limsup_{n \in \mathbb{N}} |x_n|$.
30572
Intersection of nested closed bounded convex sets in Euclidean space
132382
Showing a set is nowhere dense in $C([0,1])$
113922
Proof that the intersection of any finite number of convex sets is a convex set
158018
Everywhere Super Dense Subset of $\mathbb{R}$
135650
Sequences in Hilbert spaces
121095
Is convex hull of a finite set of points in $\mathbb R^2$ closed?
35857
Characterization of log-convexity
17336
Least norm in convex set in Banach space
17159
Proof of Closest Point Theorem in Hilbert Space
23520
A property of Littlewood-Paley decomposition
52231
Prove or disprove {$\sum_{i=1}^n x_i^2 = 1$} is convex
149536
Why is the  $L_p$ norm strictly convex for $1<p<\infty?$
74608
Convex function as supremum of countably many affine functions
158399
Show that $\{(x_1,x_2):x_1x_2\geq4,x_1>0,x_2>0\}$ is a convex set
156101
Is the convex hull of closed set in $\mathbb R^{n}$ is closed?