Here are some examples of the various kinds of isolated singularities:
- removable: Consider
for an entire function. Then has a removable singularity at 1;;z_0. - Poles:
has a pole of order 1;; at . has a pole of order 1;; at . In general, you can get an idea of the order of the poles by looking at the highest degree term in the principal part of the Laurant series. - Essential Singularities: Some examples of essential singularities at 1;;
are and .