In these examples, the taxonomy 2000A includes category node 2001A through 2010A related to each other using relation types A, B and C. Taxonomy 2000B includes categories 2001B through 2008B related to each other using relation types B, C and D. Taxonomy 2000C includes categories 2001C through 2012C related to each other using relation types C, D and E. In this example, taxonomies 2000A and 2000B