$(e_1,e_2,..)$ is not a Schauder basis of $\ell^\infty$
59929
Why is $(e_n)$ not a basis for $\ell_\infty$?
94077
Proof of linear independence of $e^{at}$
119003
Complement of $c_{0}$ in $\ell^{\infty}$
136943
A problem with a proof about formal series in Lang's Algebra
149973
Showing the following coordinate rings are not isomorphic
113411
If $E$ is generated by $E_1$ and $E_2$, then $[E:F]\leq [E_1:F][E_2:F]$?
41069
Justifying $\,\Bbb{Z}[i]/\langle 2\rangle\cong \Bbb{Z}[X]/\langle X^2+1,2\rangle\cong \Bbb{F}_2[X]/\langle X^2+1\rangle$
135641
Algebraic independence of exponentials
70475
Proving a basis for inner product space V when $||e_j-v_j||< \frac{1}{\sqrt{n}}$.
118903
The sup norm on $C[0,1]$ is not equivalent to another one, induced by some inner product
97391
Prove that $(C^1[0,1], \|\cdot\|)$ is not a Banach space
75429
A Hamel basis for $\ell^p$?
37736
How to find a function in $ L_{2}(0,\infty)$ but not $L_{q}(0,\infty)$, $q\neq 2 $
75639
Showing that $\sqrt[3]{2}\notin\Bbb Q(\alpha_1,...,\alpha_k)$ where $\alpha_i^2\in\Bbb Q\ \forall i$
107842
Behaviour of ($\overline{a}_n)_{n=1}^{\infty}$ and ($\underline{a}_n)_{n=1}^{\infty}$
157203
Let $\{f_k\}_{k=1}^\infty\in L^{loc}_1(\mathbb R^n)$, show $\{f_k^2\}_{k=1}^\infty$ does not converge in $\mathscr{D}^\prime(\mathbb R^n)$
83595
Proving that $\mathbb{A}=\{\alpha \in \mathbb{C}: \alpha \text{ is algebraic over } \mathbb{Q} \}$ is not a finite extension