1.Previous
3.Next

of A^? are precisely the sets expressible as unions of these basic open sets. The closed sets, as usual, are those whose complement is open.

The Borel sets of A^ω are the smallest class of subsets of A^ω that includes the open sets and is closed under complement and countable union. That is, the Borel sets are the smallest σ-algebra of subsets of A^? containing all the

1.Previous
3.Next