Hi Aldo,
Hi Silvio,
Thanks a lot, Silvio, for the Colletion Ontology. I oversaw this
ontology somehow.
Am 28.06.2010 16:29, schrieb Aldo Gangemi:
Yes, I like the SWAN ontology ... I remember sometimes ago I wanted to
modularize it and submit the modules as design patterns :).
Consider that, besides the typing problem in OLO, there is a difference
between OLO and SWAN in that OLO allows for "slots" that enable a
designer to assign indexes to items directly, while SWAN does not have
indexes, although they can be inferred with a query over the
"swan:nextItem" property. SWAN has the advantage of making a clear
distinction between sets, bags and lists.
Yes, the initial and primary access method to single slots in an ordered
list should be olo:index. The secondary access method is its (currently)
optional iterator olo:next as shortcut to the next slot in the list.
In principle, with a RIF rule added to SWAN (or a SPARQL/SPIN add-on),
you can get the same results as in OLO, while being able to reason with
transitivity over a sequence relation in a list.
Considering sequencing, it'd be nice to decouple transitivity and
intransitivity (easier queries and rules), cf. the "sequence" design
pattern in ODP [3].
The transitivity re. the 'follow issue' is also very interesting. Maybe
we could also add it. However, I see then many triples in the transitive
'follow properties', which implies a more complicate change mechanism.
May one have to figure out the performances of the different approaches.
> However, why do you want to represent ordered lists, slots and items
> as [ rdf:type owl:Class ] (or rdfs:Class)?
Because I like to use here the most abstract concept of a meta model. In
the OWL world this is for me owl:Class or owl:Thing and in the RDFS
world this is for me rdfs:Resource (as the most abstract concept
overall) and rdfs:Class.
> While a list is a set mathematically speaking, is there any advantage
> in representing the lists you want to talk about as sets?
>
> This has some bad consequences. In your example, SexMachine and
> GoodFoot are inferred to be [ rdf:type owl:Class ], not only [
> rdf:type mo:Track ]. Therefore James Brown results to be the author
> (foaf:made) of an owl:Class (SexMachine), ehich is at least awkward
> :).
Thanks for that hint, Aldo. I removed the rdfs:range from olo:item in
the v 0.5 version[1].
Feel free to add further comments, suggestions, critics.
Cheers,
Bob
[1]
http://motools.svn.sourceforge.net/viewvc/motools/orderedlistsonto/branches/orderedlistsonto_v03/rdf/orderedlistontology.n3
