\[\Large\textbf{Minimize the number of repeater-nodes}\]
\[\Large\textbf{and, if possible,}\]
\[\Large\textbf{minimize the number of time-steps}\]
\[\Large\textbf{in broadcasting a message}\]
\[\Large\textbf{within a communication network}\]
\[\Large\textbf{which is based on a circulant graph.}\]