Hi everyone, I'm trying to solve some Lebesgue problems from my exercise book and I got stuck in some of them:
Prove that if a set A has zero measure, then its interior is empty. I've thinking on suppose the contrary and find an open subset of A with positive measure, but I'm not really sure if it's the right way.
True or false: f is integrable if and only if |f| is integrable over Rn. I know that if f is measurable, then it's correct, but here there is no previous condition so I don't know if the statement is true or false.
Could you give me some tips to solve it? Thanks in advance.
