Proving that both $F_\sigma $ and $G_\delta$ sets are $\sigma $-algebras
29637
$\sigma$-algebra of sets that are both $G_\delta$ and $F_\sigma$
97024
If $F/k$ normal, $g,h \in F[X]$ monic irreducible factors of $f \in k[X]$, then $\exists\ \sigma \in Aut(F/k)$ s.t. $g^\sigma = h$.
43894
If $S$ is an infinite $\sigma$ algebra on $X$ then $S$ is not countable
42084
Set of points of continuity are $G_{\delta}$
55157
$\sigma$-algebras on a countable set is generated by partitions of the set
144359
A random variable that induces a $\sigma$-algebra the same as the one in the sample space
111129
Show that $[K:F]_s = [K:L]_s [L:F]_s$ and $[K:F]_i = [K:L]_i [L:F]_i$.
147783
Showing a sigma algebra is the union of certain collection of sigma algebras
137982
Show that $\textbf{ZF}$ shows $\phi$ is $\Delta_1$
19294
‎If ‎‎$‎X$ is an infinite-dimensional Banach space and ‎‎$‎‎u‎\in ‎B(X)‎$ ,then $\bigcap_{v\in K(X)}\sigma(u+v) =\cdots$
19996
Example where union of increasing sigma algebras is not a sigma algebra
157426
Proving that:$\int_X f_n g \, d\mu \to \int_X fg \, d\mu$ for all $g$ in $\mathscr{L}^q (X)$
10702
Show that $\left\{A\subset\Omega: A~\text{ is countable or }A^C\text{ is countable}\right\}$ is a $\sigma$-algebra
109570
How to show that the set of points of continuity is a $G_{\delta}$
63860
Measure of Dependence Between Two $\sigma$-algebras
98816
How to prove that $\{f+g<a\}=\bigcup_{r\in{\Bbb Q}}(\{f<r\}\cap\{g<a-r\})$?
96286
Proving that sum of two measurable functions is measurable.