- #1

- 191

- 0

## Main Question or Discussion Point

we can prove that:

the intersection of a finite number of open sets is open.

how about:

the intersection of any number of open sets?

it's maybe not open.but how to prove it or the example?

the intersection of a finite number of open sets is open.

how about:

the intersection of any number of open sets?

it's maybe not open.but how to prove it or the example?