Let us suppose that a set of documents

{Dl, D2, D3, D4, D5, D6, D7, D8}

has been classified into four groups, that is

{(Dl, D2), (D3, D4), (D5, D6), (D7, D8)}

Furthermore these have themselves been classified into two groups,

{((Dl, D2), (D3, D4)), ((D5, D6), (D7, D8))}

The dendrogram for this structure would be that given in Figure 4.7. To represent this in storage by means of ring structures is now a simple matter (see Figure 4.8).

The Di indicates a description (representation) of a document. Notice how the rings at a lower level are contained in those at a higher