Edward, For (c), easiest choice is the identity function. For (a), one of the easiest choices is the doubling function, f(x) = 2x. For (b), I can't think of a surjective function that's not injective. Someone on this site should have further comments on that. Thanks, Ben
> Date: Fri, 12 Oct 2012 00:30:11 -0400 > From: email@example.com > To: firstname.lastname@example.org > Subject: Functions w/ Injective and Surjective > > How could I give an example that function f: ??? that is > (a.) injective but not surjective > (b.) surjective > (c.) and both bijective > > Using N obviously it involves Natural numbers. How can this be shown?