- #1

- 107

- 0

*open*and disjoint sets whose union is Y.

This doesn't quite make much intuitive sense to me.

For example, consider R with the usual topology. Then clearly, Y= [0,1] union [2,3] is not connected. That means you CAN find two non-empty, open and disjoint, sets whose union is Y. But what are they?

I can't seem to think of 2 open sets in R whose union is [0,1] union [2,3].