\par
\section{Data Structure}
\label{section:DSTree:dataStructure}
\par
The {\tt DSTree} object has a very simple data structure.
It contains a {\tt Tree} object to represent the tree fields
of the domains and separators, and an {\tt IV} object to hold the
map from the vertices to the domains and separators.
\begin{itemize}
\item {\tt Tree *tree} :  pointer to the {\tt Tree} object 
\item {\tt IV *mapIV} : pointer to the {\tt IV} object that holds
the map from vertices to domains and separators.
\end{itemize}
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% \begin{tabular}{|l|l|}
% \hline
% {\tt tree}  & pointer to the {\tt Tree} object \\
% {\tt mapIV} & pointer to the {\tt IV} object that holds \\
%             & the map from vertices to domains and separators. \\
% \hline
% \end{tabular}
% \end{center}
