Question

If f:A->B and g: B->A. Is this enough to say f and g are onto?

Answer 1

Well it could be that \(\forall x\quad f(x) = b\in B\) and \(\forall x\quad g(x) =a\in A\). they'd both be constants and not onto.

Answer 2

wait.. hold on

Answer 3

oh I see it now,