- From: Ian Horrocks <horrocks@cs.man.ac.uk>
- Date: Sun, 2 Nov 2003 10:44:08 +0000
- To: Graham Klyne <gk@ninebynine.org>
- Cc: www-rdf-logic@w3.org
OWL's datatype support is currently fairly rudimentry and does not include any means of expressing the kinds of knowledge you describe. One way to do so, while still maintaining decidability (for OWL DL at least) would be to extend the language with n-ary datatype predicates (see, e.g., [1]). Another way would be to include arithmetic built-ins in an expressive extension such as horn rules (see, e.g., [2]), but this would almost certainly make the language undecidable. Ian [1] http://www.cs.man.ac.uk/~horrocks/Publications/download/2003/PaHo03a.pdf [2] http://www.cs.man.ac.uk/~horrocks/DAML/Rules/ On October 31, Graham Klyne writes: > > [I originally asked this on RDF-IG, but realize this is probably the better > forum. #g] > > Does anyone have any examples of using OWL to perform RDF-datatype-related > inferencing? > > I'm thinking of datatypes, such as numbers, for which additional properties > are used to define additional relations, such as addition over numbers. > > For example, given: > > :vehicle :seatedCapacity "30"^^xsd:integer . > :vehicle :standingCapacity "10"^^xsd:integer . > > and knowledge that the total capacity is seated capacity + standing > capacity, that one might infer: > > :vehicle :totalCapacity "40"^^xsd:integer . > > This might be expressed thus using CWM-style rules: > > { ?v :seatedCapacity ?c1 . > ?v :standingCapacity ?c2 . > (?c1 ?c2) math:sum ?c3 . } > => > { ?v :totalCapacity ?c3 . } > > It seems to me that to express such relations one must have a form of > universal quantification. But I'm not sure if anything in OWL performs > such a purpose, so I struggle to see how one might express an idea like > that above. > > Behind this question, I'm trying to see if there's a way to abstract the > rules of datatype properties away from particular application > domain. (i.e. using just RDF statements, and not rules, to express ideas > like the example above, appealing only to application-independent rules > defined on datatyped values.) Currently I'm not seeing any way to do this, > but before I give up I wanted to see how OWL (as the major thrust for Sweb > inference) deals with such issues. > > #g > > > ------------ > Graham Klyne > For email: > http://www.ninebynine.org/#Contact
Received on Sunday, 2 November 2003 05:46:42 UTC