- From: Jonathan Borden <jonathan@openhealth.org>
- Date: Thu, 25 Apr 2002 11:00:43 -0400
- To: <www-webont-wg@w3.org>, "Pat Hayes" <phayes@ai.uwf.edu>
now we're talkin' *** Jonathan *** to be understood as implying that as a member of the DTTF, I am leaning heavily toward this proposal, reserving the right to change my mind at some later date, perhaps tomorrow ----- Original Message ----- From: "Pat Hayes" <phayes@ai.uwf.edu> To: <www-webont-wg@w3.org> Sent: Wednesday, April 24, 2002 10:22 PM Subject: RE: ACTION: task force unasserted triples > A few more observations about the owl:Dark proposal > (http://lists.w3.org/Archives/Public/www-webont-wg/2002Apr/0290.html). > > Given an RDF graph G, consider the subgraph containing all the > triples in G that do not contain any uriref that occurs as the > subject of a triple of the form > > aaa rdf:type owl:Dark . > > which is rdfs-entailed by G, ie which is in the rdfs-closure of G. > Call this the 'light' subgraph of G, light(G). Any RDF graph has a > unique light subgraph which can be figured out by an RDFS reasoner. > > (This allows implicit 'darkening', eg by defining an rdfs:subClassOf > owl:Dark and asserting something to be in the subclass, or by using > rdfs:range. An alternative proposal would be to require the triple to > occur in the graph explicitly. While syntactically simpler, that > would complicate the relationship between RDFS and OWL since drawing > a valid conclusion in RDFS could alter the 'darkness' of the > vocabulary. ) > > The desired semantic relationship between the languages can then be > stated as the condition: Any satisfying OWL-interpretation of G is a > satisfying rdfs-interpretation of light(G). > > Lemma: If S rdfs-entails G, then light(S) rdfs-entails light(G). > > This means that drawing valid RDFS conclusions from some OWL (even on > the 'dark' vocabulary) isn't going to produce any unwanted > conclusions. It might produce some conclusions that are dark, but it > isn't going to produce any light ones that it shouldn't produce, ie > that OWL would find embarrassing. > > More later, hopefully with some test cases. > > Pat > > -- > --------------------------------------------------------------------- > IHMC (850)434 8903 home > 40 South Alcaniz St. (850)202 4416 office > Pensacola, FL 32501 (850)202 4440 fax > phayes@ai.uwf.edu > http://www.coginst.uwf.edu/~phayes > >
Received on Wednesday, 24 April 2002 22:48:16 UTC