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\begin{enumerate}[{1.}4]
\item  None of the neighbors of $B$ in the hidden area of $S$ should be receiving data. It means that there should not be a successful transmission between a node located in the hidden area of the node $B$ and any neighbors of $B$ located in the hidden area of $S$. 
\item  There should be no RTS message transmission in the hidden area of $S$.
\item  There should be no CTS message transmission in the hidden area of $S$ (the source of this CTS is beyond the interference area of $B$; otherwise the ongoing CTS message would not take place).
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