Re: Higher-arity to RDF binary

Right, but it is unfortunate that we do not have an established
*standard* way to represent higher-arity relations.  Instead we have
*multiple* ways to do it, and different people do it different ways,
which means that software cannot automatically recognize them as
higher-arity relations.  

For example, if we had a standard "marker" property like this:

  :higherArityRelation a rdfs:Property ;
     rdf:comment """A higher-arity relation (i.e., not restricted 
                    to binary relations) between the subject and the
                    items in the object list.  The object must be a
                    list; each element of the list participates as
                    one of the participants in the relation.  Thus,
                    a tertiary relation uses a list of two items.""" .

then for the diagnosis use case in
http://www.w3.org/TR/swbp-n-aryRelations/#useCase1
we could write something like the following:

  foo:has_diagnosis a :higherArityRelation .
  
  foo:christine foo:has_diagnosis ( foo:Breast_Tumor foo:HIGH ) .

and software could recognize this as a tertiary relation, perhaps
optimizing or rendering it differently.

David



On Sat, 2010-05-15 at 16:59 +0200, Jakub Kotowski wrote:
> Hi,
> 
> Jitao Yang wrote:
> > Regarding arity, RDF is binary,
> > are there any good methods for encoding higher-arity relations in a graph?
> 
> This is a frequent question about RDF, see for example:
> 
> http://www.w3.org/TR/swbp-n-aryRelations/
> http://www.w3.org/2004/08/12-Yoshio/onNaryRelations.html
> 
> and some discussion of the triple choice:
> http://blogs.sun.com/bblfish/entry/why_binary_relations_beat_tuples
> 
> Jakub
> 
> > 
> > Thanks,
> > Jitao
> > 
> 
> 
> 
> 


-- 
David Booth, Ph.D.
Cleveland Clinic (contractor)

Opinions expressed herein are those of the author and do not necessarily
reflect those of Cleveland Clinic.