## 7.3. Measures

### Examples 7.3.7(d): Measurable Sets

Suppose*and*

**A***are measurable. Then*

**B***comp(*and

*)***A***comp(*are also measurable, and because of the previous exercise the set

*)***B***comp(*is measurable.

*) comp(***A***)***B**But since

the setcomp() comp(A) = comp(BA)B

*comp(*is measurable. Finally, the complement of

**A***)***B***that*set must be measurable, which is what we wanted to prove.