--- In quizbowl_at_yahoogroups.com, koszul <no_reply_at_y...> wrote:
> You're confusing what my claim is. I never claimed that closed
> sets cannot be countable, but rather that there are nonclosed
> countable sets and so the statement as I remember it
> that "countable sets are examples" from the question means that
> closed cannot be a valid answer given that not all countable sets
> are examples of closed sets. My request for the wording, to see
> whether I've forgotten a clause, still stands.
Hmm. Well, hopefully R. won't mind my posting the first sentence:
"6. Considered as subsets of the real line, this term describes any
single point or countable set, any interval that includes its
endpoints, and any finite union of such sets."
So, the question is indeed flawed, as there do exist sets which are
countable but not closed.
--Paul