deletions | additions       diff --git a/header.tex b/header.tex  index 801ffe1..bf48424 100644  --- a/header.tex  +++ b/header.tex 
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%\usepackage{amsmath}  \operatorname{sgn}  \newtheorem{theorem}{Theorem}  \newtheorem{proof}{Proof}   \newtheorem{definition}{Definition}