--- a/notes/tex/preamble.tex	Sun Oct 20 16:30:56 2013 +0200
+++ b/notes/tex/preamble.tex	Mon Oct 21 20:29:08 2013 +0200
@@ -25,6 +25,7 @@
 \usepackage{mathtools}
 \mathtoolsset{showonlyrefs}
 \usepackage{csquotes}
+\usepackage{wasysym}
 
 \usepackage{beamerthemeLEA2}
 
@@ -36,5 +37,8 @@
 \newcommand{\Prob}{\mathrm{P}}
 \newcommand{\Oh}{\mathcal{O}}
 
+\newcommand{\abs}[1]{\left\vert #1 \right\vert}
+\newcommand{\powerset}[1]{\mathcal{P}\left( #1 \right)}
 \newcommand{\setnot}[1]{\overline{#1}}
 \newcommand{\setsymdiff}{\,\triangle\,}
+\newcommand{\defeq}{\mathrel{\vcenter{\baselineskip0.5ex\lineskiplimit0pt\hbox{\scriptsize.}\hbox{\scriptsize.}}}=}