Hello! Thanks for reading.
I need to use the fact that R is a baire space somewhere, but I just don't seem to be able to prove it. I'm not even sure if it's trivial or not (meaning, if it's even required to prove it), but I guess I can't take the risk. Moreover, it's disturbing I don't know how too.
I know that R is a complete metric space.
I've read that complete spaces are baire spaces, but I haven't got the proof for that.
My definition for baire space is one of the following (which are equivalent, I've proved that):
1) every countable intersection of dense open sets is a dense set.
2) every countable unification of non-dense (not sure of the term) sets has an empty interior.
Can't see why R satisfies that, nor how to prove the more general claim, that complete space => Baire space.