deletions | additions       diff --git a/header.tex b/header.tex  index f9eea69..4f7ddb7 100644  --- a/header.tex  +++ b/header.tex 
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%\usepackage{natbib}  %\bibliographystyle{plainnat}  \usepackage[russian]{babel}  \newtheorem{theorem}{Theorem}  \newtheorem{proof}{Proof}   \newtheorem{definition}{Definition}