Re: relational data as a bona fide member of the SM

On 03/11/11 19:19, Alexandre Riazanov wrote:
> I have been asking this sort of questions for a while and the only
> decent answer I know is that
> Description Logics only work with unary and binary predicates (classes
> and properties),
> although I believe RDF was initially developed independently from the DL
> and OWL work.

It is true that DL (and thus OWL DL) is conceptually based on 
unary/binary relations but this was hardly the historical reason for RDF 
being defined this way in the first place.

However, somewhat ironically, OWL ontologies are a good example of 
pieces of data that suffer a lot from forced triplification. OWL has a 
native (functional style) syntax that is quite easy to parse, whereas 
its RDF serialisation requires multiple passes over the data to group 
triples that belong to the same axioms (because the triples that form a 
single OWL statement can be distributed over a whole file, in random 
order). So one can actually say that OWL users, while preferring to 
model information in a *semantic* world of binary relations, are not 
very well served with a *syntax* that requires n-ary statements to be 
encoded in triples which do not allow have a reasonable meaning unless 
they can be re-assembled appropriately.

(This is not an argument for or against OWL/RDF/triples/relations/etc. 
-- just an observation that some might find interesting.)


Dr. Markus Krötzsch
Department of Computer Science, University of Oxford
Room 306, Parks Road, OX1 3QD Oxford, United Kingdom
+44 (0)1865 283529     

Received on Thursday, 3 November 2011 23:14:46 UTC