Is $\{x \in \Omega \mid u(x) = 0, \partial_{x_j} u(x) \neq 0\}$ a null set?
9350
Gradient of Sobolev function on level sets
131444
Local maximum implies derivative is $0$
3682
If $V = \text{null}(\textsf{T}-\lambda\textsf{I}) \oplus \text{range}(\textsf{T}-\lambda\textsf{I})$, then prove that $\textsf{T}$ is diagonalizable
123806
How do I show that the integral of $e^{inx}$ over a set of measure $1$ is nonzero for some nonzero $n$?
113778
Show that $E=\{(x,\alpha)\mid 0\leq \alpha<|f(x)|\}$ is measurable if $f$ is measurable.
83185
How to show countability of $\omega^\omega$ or $\epsilon_0$ in ZF?
6270
Poincaré inequality for a subspace of $H^1(\Omega)$
1307
Infimum and supremum of the empty set
93684
Show that $\mu (E \setminus A)>0$ if $A$ is a nonmeasurable subset of $X$ and $A \subseteq E$, $E$ is measurable.
35631
$H_0(X,A) = 0 \iff A \cap X_i \neq \emptyset \forall $ path-components $X_i$
108642
$e^A$, where $A= \begin{bmatrix} 0 & \omega \\ -\omega& 0 \end{bmatrix}$
30079
Is for open connected $U$ the set $U_\varepsilon$ for small $\varepsilon$ connected?
54957
The necessary and sufficient condition for a unit element in Euclidean Domain
21881
Prove that $\forall\alpha\geq\omega$, $|L_\alpha|=|\alpha|$ without AC
32458
Does the rank-nullity theorem hold for infinite dimensional $V$?
91022
How do I prove that a subspace of a vector space $X$ is the null space of some linear functional on $X$?
40458
Does scaling lead to weak convergence to the null function?