# Math Help - Prove that a set is denumerable iff...

1. ## Prove that a set is denumerable iff...

Prove that a set T1 is denumerable if and only if there is a bijection from T1 onto a denumerable set T2

2. I assume a denumerable set is one that has a bijection onto the set of natural numbers. In this case, recall that a composition of two bijections is again a bijection.