Is Sobolev space $H^{s}(\mathbb R),$ for $s>\frac{1}{2},$ closed under point wise multiplication?
33397
Sobolev space $H^s(\mathbb{R}^n)$ is an algebra with $2s>n$
74764
Dimension for a closed subspace of $C[0,1]$.
73690
If $\mathbb R^3\setminus V$ connected where $V$ is the subspace generated by $\{(1,1,1),(0,1,1)\} $
145668
Subspaces of $\ell^{2}$ and $\ell^{\infty}$ which are not closed?
29655
$L^p$ and $L^q$ space inclusion
14840
$c_0$ is a closed subspace of $l^{\infty}$
95234
Quasi-components in compact space
49759
Proving that $i\hbar\frac{\partial}{\partial \mathbf{p}}$ is the operator of $\mathbf{x}$ in momentum space
60981
Understanding relation between Quotient Space and $S^1$
115794
When is the vector space of continuous functions on a compact Hausdorff space finite dimensional?
44955
Can $\mathbb CP^n$ be the boundary of a compact manifold?
98391
example of a nonempty subset is closed under scalar multiplication but not a subspace
80735
Show that $C_0([a, b], \mathbb{R})$ is not $\sigma$-compact
37206
$\mathbb{R}^n\times\{0\}$ has measure zero in $\mathbb{R}^{n+1}$
96363
How to show that $\mathbb R^n$ with the $1$-norm is not isometric to $\mathbb R^n$ with the infinity norm for $n>2$?
158011
$C_c^{\infty}(\mathbb R^n)$ is dense in $W^{k,p}(\mathbb R^n)$
127522
Space $\mathcal{L}^p(X, \Sigma, \mu)$ is separable iff $(\Sigma, \rho_\Delta)$ is separable