{
  \noindent
  \begin{center}
  \framebox{
    \vbox{
      \hbox to 5.78in { {\bf CS 229r - Spectral Graph Theory
      		in Computer Science} \hfill Prof. Salil Vadhan }
      \vspace{4mm}
      \hbox to 5.78in { {\Large \hfill Problem Set \psnum  \hfill} }
      \vspace{2mm}
      \hbox to 5.78in { {\em Harvard SEAS - Fall 2020 \hfill Due: \duedate  }}
    }
  }
  \end{center}
  \vspace*{4mm}
}

\if\psnum0
This problem set is to help you review background material and gauge your preparation for the course.  You are not expected to have seen all of these problems before, only to have the background needed for their solutions.  It is optional but highly recommended.  Your solutions will be graded for the sake of feedback, but the grades will not count.

Your problem set solutions must be typed (in e.g.~\LaTeX) and submitted on Gradescope. You are allowed 12 late days for the semester, of which at most 5 can be used on any individual problem set. (1 late day = 24 hours exactly). Please name your file \texttt{ps{\psnum}-}lastname\texttt{.*}.

In general, the problem sets in the course may require a lot of thought, so be sure to start them early.  You are encouraged to discuss the course material and the homework problems with each other in small groups (2-3 people). Identify your collaborators on your submission.  Discussion of homework problems may include brainstorming and verbally walking through possible solutions, but should not include one person telling the others how to solve the problem.  In addition, each person must write up their solutions independently, and these write-ups should not be checked against each other or passed around.

Strive for clarity and conciseness in your solutions, emphasizing the main ideas over low-level
details. Do not despair if you cannot solve all the problems! Difficult problems are included
to stimulate your thinking and for your enjoyment, not to overwork you. %*'ed problems are extra credit.
\else
Your problem set solutions must be typed (in e.g.~\LaTeX) and submitted on Gradescope. You are allowed 12 late days for the semester, of which at most 5 can be used on any individual problem set. (1 late day = 24 hours exactly). Please name your file \texttt{ps{\psnum}-}lastname\texttt{.*}.

The problem sets may require a lot of thought, so be sure to start them early.  You are encouraged to discuss the course material and the homework problems with each other in small groups (2-3 people). Identify your collaborators on your submission.  Discussion of homework problems may include brainstorming and verbally walking through possible solutions, but should not include one person telling the others how to solve the problem.  In addition, each person must write up their solutions independently, and these write-ups should not be checked against each other or passed around.

Strive for clarity and conciseness in your solutions, emphasizing the main ideas over low-level
details. Do not despair if you cannot solve all the problems! Difficult problems are included
to stimulate your thinking and for your enjoyment, not to overwork you. %*’ed problems are Sextra credit.
\fi