deletions | additions       diff --git a/section_begin_itemize_item_Err__.tex b/section_begin_itemize_item_Err__.tex  index 02c0ec7..14ef1ca 100644  --- a/section_begin_itemize_item_Err__.tex  +++ b/section_begin_itemize_item_Err__.tex 
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Err_{v,w} = \left\{\begin{matrix}  0, & j_1 < j_2 \\   1, & j_1 > j_2  \end{matrix}\right.\\ \end{matrix}\right.  \end{equation}  \begin{equation}  Err~(X,Y) = \sum_{\substack{v\neq w\\  v,w\epsilon \{X\},\{Y\}}}Err_{v,w}  \end{equation}