6.3 corrections

document/chapters/chapter_6/sections/3_mapreduce_service.tex

@@ -112,7 +112,7 @@ \subsection{MapReduce Master}
     \label{fig:master_petri_net_3}
 \end{figure}
 
-While the reduce function is being applied, the region token is removed due to the fact that no more splits for this region needs to be mapped (\textit{figure \ref{fig:master_petri_net_4}}). \textbf{A failure can also happen here, since the Reduce Worker can disconnect during the reduce function execution; in this case, the region token is restored and a new Reduce Worker is required}.
+While the reduce function is being applied, the region token is removed due to the fact that no more splits for this region need to be mapped (\textit{figure \ref{fig:master_petri_net_4}}). \textbf{A failure can also happen here, since the Reduce Worker can disconnect during the reduce function execution; in this case, the region token is restored and a new Reduce Worker is required}.
 
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