\part{Residue theory}


\begin{definition}[Pole]
\end{definition}

\begin{definition}[Residue]
\end{definition}

\begin{definition}[Laurent series]
\end{definition}

\begin{definition}[Meomorphic function]
\end{definition}



\begin{theorem}[Residue theorem]
\end{theorem}



\begin{theorem}[Picard's little theorem]
\end{theorem}
\begin{theorem}[Picard's great theorem]
\end{theorem}

\section{Application to real analysis}

- Euler function 
\[ \varphi(q) = \prod^{\infty}_{k=1} (1-q^k), |q| < 1\]
