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\begin{document}
\lecture{Titel}{Name}{Datum}

\section{Abschnitt 1}
\begin{theorem}
\end{theorem}
\begin{proof}
\end{proof}

\begin{corollary}
\end{corollary}

\begin{lemma}
\end{lemma}

\begin{observation}
\end{observation}

\begin{definition}
\end{definition}

\end{document}
