deletions | additions       diff --git a/header.tex b/header.tex  index c1205ab..bd4c4b4 100644  --- a/header.tex  +++ b/header.tex 
...
\newcommand{\G}{{\bf G}}  \newcommand{\Atoms}{{\bf P}}  \newcommand{\mo}{\text{\rm Mod}}  \newcommand{\O}{{\bf \renewcommand{\O}{{\bf  O}} \newcommand{\N}{N}  \newcommand{\T}{\mathcal T}