Not Borel measurable set
6675
Lebesgue measurable set that is not a Borel measurable set
47187
Proving the measure of an increasing sequence of measurable sets is the limit of the measures
64840
A Banach space that is not a Hilbert space
73619
Why is $(\mathbb{R}, \mathcal{P}(\mathbb{R}))$ called a measurable space when actually is not?
130981
Co-countable measure on uncountable set
151637
How do we prove that this set is not manifold?
70645
Borel set preserved by continuous map
125190
Convergence to function that is not measurable
98580
Lebesgue-measurable sets requiring the Axiom of Choice to construct
94980
Measurable functions in a countable co-countable $\sigma$-algebra
138055
If $A$ has a positive Lebesgue measure then there exist subsets which are not measurable
41683
Pre-image of a measurable set A is always measurable?
60032
If the measure of union = sum of outer measures, then the sets are measurable
3023
Construction of a Borel set with positive but not full measure in each interval
128332
Counterexample to "Measurable in each variable separately implies measurable"
116676
Examples of uncountable sets with zero Lebesgue measure
148328
Example of a function $f$ on $X$ to $\mathbb{R}$ which is not $X$-measurable but $|f|$, and $f^2$ are measurable.