deletions | additions       diff --git a/header.tex b/header.tex  index 7d71168..ea2efc9 100644  --- a/header.tex  +++ b/header.tex 
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%\usepackage{amsmath}  \DeclareMathOperator{\sign}{sign} \DeclareMathOperator{\sgn}{sgn}  \newtheorem{theorem}{Theorem}  \newtheorem{proof}{Proof}