undesirable. If one attaches a label to the root graph, it is probably
not the desired effect to have the label used by all subgraphs. Rather
than listing the graph attribute at the top of the graph, and the
-resetting the attribute as needed in the subgraphs, one can simple defer
-the attribute definition if the graph until the appropriate subgraphs
+resetting the attribute as needed in the subgraphs, one can simply defer
+the attribute definition of the graph until the appropriate subgraphs
have been defined.
<P>
If an edge belongs to a cluster, its endpoints belong to that cluster.