# Isolated singularities, poles and removable singularities

Let $f$ be holomorphic with an isolated singularity at $z_0$. Suppose that $\exists M,m,\epsilon$ positive numbers such that $|f(z)| \leq M|z-z_0|^{-m}$ for $0<|z-z_0|<\epsilon$. Prove that $z_0$ is either a removable singularity or a pole of order $m$.

That's not quite right: it is either removable or a pole of order $\le m$. And you want $m$ to be an integer. – Robert Israel Nov 20 '12 at 2:08
Hint: What kind of singularity does $(z - z_0)^m f(z)$ have at $z_0$?