\usepackage{refstyle}
\newref{eqn}{%
name={eqn~},
names={eqns~},
Name={Eqn~},
Names={Eqns~},
rngtxt={\ to~},
lsttxt={\ and~},
refcmd=(\ref{#1})
}
\newref{prop}{%
name={property~},
names={properties~},
Name={Property~},
Names={Properties~},
rngtxt={\ to~},
lsttxt={\ and~},
refcmd=(\ref{#1})
}

\usepackage{geometry}
\geometry{a4paper}
\usepackage{amsmath}
\usepackage{graphicx}
\DeclareGraphicsRule{.tif}{png}{.png}{`convert #1 `dirname #1`/`basename #1 .tif`.png}
\usepackage[colorlinks=true, pdfstartview=FitV, linkcolor=blue, citecolor=blue, urlcolor=blue, plainpages=false]{hyperref}
\usepackage{url}
\usepackage[numbers]{natbib}
\bibliographystyle{plainnat}
\usepackage{ifthen}
\usepackage{xspace}
\usepackage{cctbx_notations}