- #1
ballzac
- 104
- 0
Homework Statement
Give an example of a map from the set N of positive integers to itself which
is surjective but not injective.
Homework Equations
The Attempt at a Solution
It's easy to come up with an example, but I'm not sure on notation.
Here's how I've written it, but I know it's not quite right. I'm sure you can see the function that I am meaning to give. Any help with the notation would be appreciated. If it's not clear what function I mean, let me know and I will put it into words :)
[tex]\lbrace f:f(1)=1, f(s)=s-1,s>1\rbrace[/tex]