% Fonts and characters.
\let\altemph\textsl
\let\strong\textbf
\let\code\texttt
\let\const\textsf
\newcommand*{\txtbksl} {\symbol{"5C}}% \
\newcommand*{\txtcaret}{\symbol{"5E}}% ^
\newcommand*{\txtunder}{\symbol{"5F}}% _
\newcommand*{\txtlcurl}{\symbol{"7B}}% {
\newcommand*{\txtrcurl}{\symbol{"7D}}% }
\newcommand*{\txttilde}{\symbol{"7E}}% ~
\newcommand*{\N}{\mathbb{N}}  % requires amssymb
\newcommand*{\Z}{\mathbb{Z}}  % requires amssymb
\newcommand*{\Q}{\mathbb{Q}}  % requires amssymb
\newcommand*{\R}{\mathbb{R}}  % requires amssymb
\newcommand*{\bigOh}{\mathcal{O}}

% Abbreviations of latin phrases.
\newcommand*{\ie}{\emph{i.e.}}
\newcommand*{\eg}{\emph{e.g.}}
\newcommand*{\etc}{\emph{etc}}
\newcommand*{\vs}{\emph{vs.}}

% Redefined symbols from amssymb.
\renewcommand*{\emptyset}{\varnothing}
\renewcommand*{\iff}{\mathrel{\Leftrightarrow}}
\renewcommand*{\implies}{\mathrel{\Rightarrow}}
\renewcommand*{\ge}{\geqslant}
\renewcommand*{\le}{\leqslant}

% For algorithms.
\let\proc\textsc
\let\kw\textbf
\let\var\textsl
\newcommand*{\eq}{\mathrel{==}}
\renewcommand*{\neq}{\mathrel{!\!=}}
\renewcommand*{\leq}{\mathrel{<=}}
\renewcommand*{\geq}{\mathrel{>=}}
\renewcommand*{\gets}{\mathrel{=}}
\newcommand*{\opgets}[1]{\mathrel{#1\!=}}
\newcommand*{\True}{\const{True}}
\newcommand*{\False}{\const{False}}
\newcommand*{\None}{\const{None}}
\newcommand*{\cmod}{\mathbin{\%}}

% Math macros.
\newcommand*{\comp}[1]{\overline{#1}}  % complement
\newcommand*{\emptystr}{\varepsilon}  % empty string
\newcommand*{\lequiv}{\mathrel{\ \Longleftrightarrow\ }}
\newcommand*{\lxor}{\oplus}
\newcommand*{\floor}[1]{\lfloor#1\rfloor}
\newcommand*{\ceil}[1]{\lceil#1\rceil}

% Like {itemize} but using less vertical space.
\newenvironment*{points}
 {\ifvmode\else\unskip\par\fi\begin{list}{$\bullet$}
   {\setlength{\topsep}{.25ex plus .125ex minus .1825ex}
    \setlength{\itemsep}{\topsep}\setlength{\parsep}{0ex}
    \setlength{\leftmargin}{1.75em}\setlength{\labelsep}{.5em}
    \setlength{\labelwidth}{1.75em}}\ignorespaces}
 {\ifvmode\else\unskip\fi\end{list}\ignorespaces}

% Spacing macros with default argument.
\newcommand*{\vstretch}[1][1]{\vspace*{\stretch{#1}}}
\newcommand*{\hstretch}[1][1]{\hspace*{\stretch{#1}}}

% 236-specific.
\newcommand*{\LI}{\textsl{LI}}  % for loop invariants