# Math Help - prove or disprove

1. ## prove or disprove

there exists f: R-R, continuous, but not one to one, such that f(V) is open for any open subset V of R.

Any ideas will be appreciated, thanks!

2. Originally Posted by violetsf
there exists f: R-R, continuous, but not one to one, such that f(V) is open for any open subset V of R.

Any ideas will be appreciated, thanks!
f(x) = x^2

3. it is not R-R

4. Originally Posted by violetsf
it is not R-R
So you want an onto map also?

5. yes
Originally Posted by ThePerfectHacker
So you want an onto map also?