Hello. How you say that Garfield (an individual) is a Cat (a collection of individuals)? If you use the same relation "is a" you might be in logical troubles....you need other role like "belongs-to" or "instance-of"... Mammal or Cat are collections of individuals... but Garfield is an individual. Normally, we try to keep separate the collections and the individuals.
The mathematical relation between a category and a simple page is "page belongs to Category". But between a categoy and any subcategory is "subcategory subset of Category". Is not the same part-of or belongs-to that subset-of. I think that it's better follow a logical point of view at the moment of represents the data. Fernando Carpani. Emanuele D'Arrigo wrote: >On 7/4/07, Olivier Dameron <[EMAIL PROTECTED]> wrote: > > >>>can a relation "is a" be used to completely replace categories? >>>Can you think of any advantage/disadvantage with this approach? >>> >>> > > > >>"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 >> >> > >But then why not to use "is a part of" or is "a type of" instead of >categories? It seems to me that categories are redundant once >you have relations, and what's worst, depending on the context, >they seem to be in-lieu of different type of relations. > >I'm confused! > >Ciao! > >Manu > > > ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ Semediawiki-user mailing list Semediawiki-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/semediawiki-user
