- From: Ian Horrocks <horrocks@cs.man.ac.uk>
- Date: Tue, 25 Mar 2003 12:52:45 +0000
- To: Dave Reynolds <der@hplb.hpl.hp.com>
- Cc: lchewhun@dso.org.sg, www-rdf-logic@w3.org
On March 25, Dave Reynolds writes: > > lchewhun@dso.org.sg wrote: > > > > I'm interested in what CANNOT be represented (declared) in OWL/DAML. Your > > comments or pointers to papers are much appreciated. > > > > What I'm hoping to do is to be able to represent constraints (or axioms or > > rules) in a DAML ontology so that an inferencing engine can check the ontology > > for consistency. > > Ian Horrocks and Benjamin Grosof have some working papers such as [1] which > compare expressivity of DAML/OWL to rule or logic programming languages. In > particular, they point out that DL languages can't represent predicates > involving multiple variables or involving predicate chains other than transitive > closures. Thus a constraint such as "my grandfather must be older than me" would > be tricky on both counts. A couple of points. DLs certainly CAN represent predicates involving multiple variables and predicate chains, it just happens that the particular DL on which DAML/OWL are based does not include these features (there are a variety of reasons for this, not the least of which is the fact that the RDF and XML type systems do not specify n-ary predicates). See [2,3] for details about DL support for datatypes (called concrete domains in DLs). I would also suggest looking at [4] (a recent paper) if you are interested in the work Benjamin and I (along with Raphael Volz and Stefan Decker) have done on integrating DAML/OWL with rule or logic programming languages. Regards, Ian [2] http://lat.inf.tu-dresden.de/~clu/papers/archive/aiml4.ps.gz [3] http://lat.inf.tu-dresden.de/~clu/papers/archive/lutzdiss.pdf [4] http://www.cs.man.ac.uk/~horrocks/Publications/download/2003/p117-grosof.pdf > > Personally I think the semantic web will need a rich constraint expression > language eventually, perhaps it could build upon something like OCL by using > path expressions to identifying the values being constrained? > > Dave > > [1] http://www.cs.man.ac.uk/~horrocks/Private/DLP/DLP-v9-brief.pdf > > -- > Hewlett-Packard Laboratories | Phone: +44-117-3128165 > Filton Road, Stoke Gifford | FAX: +44-117-3128925 > Bristol BS34 8QZ, UK | dave.reynolds@hpl.hp.com
Received on Tuesday, 25 March 2003 06:52:10 UTC