% Initialise AMS maths package
\usepackage{amsmath}
\interdisplaylinepenalty=2500
-%\usepackage{amsthm}
+\usepackage{amsthm}
\usepackage{amssymb}
\usepackage{array}
%\usepackage{subfig}
\def\R{\mathord{{\mathbb R}}} % Reals
\newcommand{\ceil}[1]{\left\lceil #1 \right\rceil}
\newcommand{\floor}[1]{\left\lfloor #1 \right\rfloor}
-\def\ave{\mathop{\rm ave}\nolimits} % memory set
\ No newline at end of file
+\def\ave{\mathop{\rm ave}\nolimits} % memory set
+\def\GF{\mathop{\bf GF}\nolimits} % Galois Field
+\def\iff{\Longleftrightarrow}
+
+\newtheorem{theorem}{Theorem}[section]
+\newtheorem{lemma}{Lemma}[theorem]
+\newtheorem{proposition}{Proposition}[theorem]
+\newtheorem{corollary}{Corollary}[theorem]
+
+\newenvironment{definition}[1][Definition]{\begin{trivlist}
+\item[\hskip \labelsep {\bfseries #1}]}{\end{trivlist}}
+