Re: Can't RDF describe collection resources?

Hi Enrico,

>> Plus, I would indeed need to make the relation between plural and singular explicit for each property with OWL property chains. (But at least, it’s possible.)
> 
> I don't get this: you just need one property chain axiom, saying that :hasComment is the composition of :hasComments (as a functional property) with :hasMember.

The thing is that I’m trying to solve the general problem here.
For the particular instance of :hasComment <=> :hasComments, you indeed need one axiom and that’s straightforward.
However, to make this work for all properties (foaf:knows, rdf:label…) I’d have to make an extra property and an extra axiom for all of them.

>> Oh, of course, I see it now.
>> The issue is that RDF in practice always works the other way round: it tends to describe individuals instead of collections.
> 
> I don't get this. Remember that with this modelling you would have at your disposal both :hasComments and :hasComment, being them redundantly constrained by the property chain axiom. You can use any of the two interchangeably. In aprticular, you can use just :hasComment and ignore systematically :hasComments in your application (but when you need to create the comments resource once forever for a newly created blog) and everything would be fine. To be more precise, you need also to state that the :hasComments property is functional, so that you could add (or refer to) a comment as a :hasComment without bothering mentioning the comments resource.


If I understand correctly, you argue that the :hasComment property is redundant, because it is equivalent to the composition of :hasComments and :memberOf.
(The :hasComments is then not redundant, for cases where the comment set is empty.)
So what I meant, is that the majority of existing data (and properties) have been described with the singular properties, because that’s just easier in RDF.

Best,

Ruben

Received on Thursday, 1 March 2012 09:48:46 UTC