Esther Brink wrote: > 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: discussions@mathforum.org >> To: discretemath@mathforum.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? >