deletions | additions       diff --git a/section_begin_itemize_item_Err__.tex b/section_begin_itemize_item_Err__.tex  index 899ac15..0f782fa 100644  --- a/section_begin_itemize_item_Err__.tex  +++ b/section_begin_itemize_item_Err__.tex 
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\begin{matrix}  0, & j_1 < j_2 \\   1, & j_1 > j_2  \end{matrix}\right. \end{matrix}\right.\\  Err~(X,Y) = \sum_{\substack{v\neq w\\  v,w\epsilon \{X\},\{Y\}}}Err_{v,w}