deletions | additions       diff --git a/Rank & centrality.tex b/Rank & centrality.tex  index bb8d79a..5652743 100644  --- a/Rank & centrality.tex  +++ b/Rank & centrality.tex 
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$$  \[a \mathrel{\mathop{\rightleftarrows}^{\mathrm{over}}_{\mathrm{under}}}b\]  $$  \end{theorem}