# Contents

## Idea

The residue of a meromorphic function $f$ at some point $\zeta \in \mathbb{Z}$ is the coefficient of $(z - \zeta)^{-1}$ (the first order pole) of its Laurent series expansion around $\zeta$. Up to a prefactor, this is what is picked up by the contour integral around that point, accrding to the Cauchy integral formula.

## References

Last revised on September 6, 2017 at 11:11:04. See the history of this page for a list of all contributions to it.