# Math Help - A countable union of F segma

1. ## A countable union of F segma

prove that

a countable union and finite intersection of (F segma - sets) is (F segma).

2. ## Re: A countable union of F segma

Hint: Use that $A$ is an $F_{\sigma}$ set iff $A$ is a denumerable union of closed sets.

3. ## Re: A countable union of F segma

ok

Ill start by this idea and Ill tell you what I get