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}

\newtheorem{lemma}{Lemma}[section]
\newtheorem{theorem}[lemma]{Theorem}
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\newtheorem{definition}[lemma]{Definition}
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\begin{document}

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\begin{center}\framebox{\parbox{\boxlength}{\bf
Course Name \hfill
Charles Lai (cjl223)
\\
CS XXXX Semester Year
\hfill
Problem Set X
}}\end{center}
\vspace{5mm}

\section*{Problem 1}

\section*{Problem 2}
(a) [``zar''; ``doz''] \\

\section*{Problem 3}

\begin{theorem}
This is a theorem statement.
\label{thm:sample-statement}
\end{theorem}

\proof{
This is a proof.
}

\end{document}