\documentclass[a4paper]{article}

\usepackage[english]{babel}
\usepackage[margin=2cm,bottom=3.5cm]{geometry}
\usepackage[hidelinks]{hyperref}
\usepackage{natbib}

\usepackage{amsmath}
\usepackage{enumitem}
\usepackage{multicol}
\usepackage{stmaryrd}

\usepackage{syntax}
\renewcommand\litleft{\bgroup\tt}
\renewcommand\litright{\egroup}
\def\<#1>{\synt{#1}}
\def\`#1'{\lit{#1}}

\usepackage{clean}
\usepackage[dvipsnames]{xcolor}
\lstdefinestyle{coloured}{
	keywordstyle=\bfseries\color{NavyBlue},
	stringstyle=\ttfamily\color{BrickRed}
}
\lstset{
	language=Clean,
	breaklines,
	tabsize=2,
	xleftmargin=\parindent,
	style=coloured
}

\usepackage{while}

\title{Imperative code interpretation in a functional style}
\author{Camil Staps}

\begin{document}

\abovedisplayshortskip=-4pt
\abovedisplayskip=\abovedisplayshortskip
\belowdisplayshortskip=7pt
\belowdisplayskip=\belowdisplayshortskip

\maketitle
\input{abs}

\begin{multicols}{2}
	\input{intro}
	\input{predefs}
	\input{ast}
	\input{eval}
	\input{interp}

	\appendix
	\input{ftypes}

	\bibliographystyle{jfp}
	\bibliography{paper}
\end{multicols}

\end{document}