Re: definition of domain

Hello Pierre-Antoine,

One of the applications I was thinking about is defaulting properties: see WAP GSM example in mail to Jeen. I would like to attach a type to some resource and let the system immedialtey fill in some of
the properties of the resource: if man A is chineese, then he is a person with yellow skin colour. If this is what you mean with prototyping, then yes, I see some classes as prototypes.

Regards,

Tom.

Pierre-Antoine CHAMPIN wrote:

> > I guess that you are afraid of the graphs: how do you know if you can propagate an arrow, attached to a
> > subclass resource, to an instance of the class. This is easy: look at the definition of the arrow as
> > resource. If you want to say something about the abstract entity 'carnivore' that you do not want to see
> > reflected in every carnivore instance, then you have to define your arrow (property) having a domain equal
> > to 'Class' or more specific: the class of which 'carnivore' is an instance. Another abstract entity in the
> > model, but I believe that it is very rare to actually describe a class itself (as abstract entity) with
> > properties not in the RDFS spec. So I don't see this as a burden.
>
> Any schema built on top of RDFS, to extends its expression power (which is weak, as you mentioned) will define properties applying to classes or other properties.
>
> I do not say what you propose is nonsense (sorry for the aggressive "definitely wrong" stuff ;-) but that it is not the best way to express it.
> Sure some clever system may "guess" whether the property applies really to the class or to each instance of it, but this is a risky guess... and tends to make specifications misleading. IMHO again :)
>
> Or do you consider classes more like prototypes ?
>
>   Pierre-Antoine