Solution
= Solution
\b[True.] Divide a <limit ordinal> $\lambda$ by $\omega$ using part a: $\lambda=\omega\alpha+n$ with $n<\omega$. If $n>0$, the right side is a successor, contrary to the limit assumption. Hence $n=0$ and $\lambda=\omega\alpha$. For a nonzero limit, $\alpha>0$; if zero is allowed as a limit, it is represented by $\alpha=0$.