From: Olivier D. <oli...@un...> - 2007-07-04 18:25:43
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On Wed, 4 Jul 2007 19:15:32 +0100, "Emanuele D'Arrigo" <ma...@gm...> wrote: > can a relation "is a" be used to completely replace categories? > Can you think of any advantage/disadvantage with this approach? No! "is a" represents specialization (e.g. Cat is-a Mammal, which means that all the instances of Cat are instances of Mammal) Categories are organized along the "is a" hierarchy, but also follow the "narrower than / broader than" relation (e.g. Algebra is a subcategory of mathematics), which is more like a kind of part-of both approaches are useful, and are complementary but not independent. I still haven't found a way to keep then in sync. olivier |