Let $U \subseteq \mathbb{C}$ be a D5008: Standard open complex set such that

(i)	$f : U \to \mathbb{C}$ is a D1392: Holomorphic function on $U$
(ii)	$C \subseteq \mathbb{C}$ is a D1403: Euclidean circle
(iii)	$$\begin{equation} \text{int}(C) \subseteq U \end{equation}$$

Then $$\begin{equation} \int_C f(z) \, d z = 0 \end{equation}$$