What can we learn from Ontologists
when constructing UBL?  [2]
Theory of formal distinctions & connections about
entities, relations, categories
Properties: identity, rigidity, unity; what changes, what
remains same?
Part-whole relations: mereotopology, aggregation,
mass/count (plurality)
Levels: physical, functional, biological, intentional,
social
Taxonomic constraints
Property analysis: legal agent, group, social entity,
organization