deletions | additions       diff --git a/Introduction.tex b/Introduction.tex  index 09c4885..8b62283 100644  --- a/Introduction.tex  +++ b/Introduction.tex 
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[a,a^+]=1=[sr,r^+s^+] \\  \\  sr^+[r,s^+]+s[r,r^+]s^++r^+[s,s^+]r+[s,r^+]s^+r=1\\  [r,r^+rr^+]=N+\frac{1}{2}-N=\frac{1}{2}  \end{equation}