deletions | additions       diff --git a/Curious Mappings.tex b/Curious Mappings.tex  index d5c83ce..83108bc 100644  --- a/Curious Mappings.tex  +++ b/Curious Mappings.tex 
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\end{bmatrix}  \end{equation}  However, we may replace $j-i$ and $j+i$ with some other functions of $i,j$ even the function itself... itself in the right conditions. Try  \begin{equation}  F_{ij}= \sum _{k=j-i}^{F_{ij}} _{k=(j-i)^2}^{j^2 -i^2}  S_k \end{equation}