- From: Dan Brickley <danbri@danbri.org>
- Date: Mon, 18 Apr 2011 17:57:26 +0200
- To: Jim McCusker <james.mccusker@yale.edu>
- Cc: Antoine Isaac <aisaac@few.vu.nl>, public-esw-thes@w3.org
On 18 April 2011 17:45, Jim McCusker <james.mccusker@yale.edu> wrote: > On Mon, Apr 18, 2011 at 10:34 AM, Dan Brickley <danbri@danbri.org> wrote: > >> IMHO foaf:focus works well for specific named entities; it works less >> well for classes, and I have been wondering how best to address this. >> >> The difference is in the pragmatics of whether we say that foaf:focus >> is a functional property. If the SKOS concept under consideration is > > I agree. I couldn't find anything that asserted that foaf:focus is a > functional property, but then FOAF is RDFS. We ought to make the functional / inverse functional flags more visible in the spec, I guess. FOAF has used DAML+OIL and later OWL alongside RDFS, so if you check in the RDF version of the spec, e.g. (not very semantically, but hey :) ... with curl xmlns.com/foaf/spec/index.rdf | grep Functional ...you'll see a bunch of other properties are indicated with functional or inverse-functional from OWL. >> #fido_the_dog, then its foaf:focus would be Fido, a Dog. And if there >> were two or three URIs around (dbpedia, freebase, VIAF, ...) for that >> self-same entity, they're all owl:sameAs each other. If the SKOS >> concept were #dogs, ... we could still use foaf:focus to point to >> (various different) classes corresponding to the class of things that >> are dogs. But having an implied sameAs amongst them all is likely to >> be less useful, less accurate, and more contentious. Since it is >> tempting to declare foaf:focus functional, this would likely mean >> nudging out the class use case to a companion property, eg. >> focusClass. Or maybe there's an OWL2 idiom that can accomodate having >> it both ways... > > The functionality of foaf:focus would not affect the actual class, > just the pun of the class. So if there were two classes that were > represented by the same concept, the puns would be declared sameAs. > This could affect any other metamodeling, but not the OWL classes > themselves. Yup, I can imagine implementors in the OWL-Full tradition doing things a little differently. Either way, it's fiddly... > On the other hand, cmo:represents is not functional, and would > therefore play nicer with existing metamodels. It also leaves room for > self-representation (x cmo:represents x, which implies that x is a > purely conceptual thing), which, if foaf:focus were defined as > functional, then if it were found that there is a real thing (class, > property, or instance) that is also represented by that thing, the > concept and the thing would be identified as sameAs. I'm reminded dimly of UMBEL here - http://umbel.org/vocabulary - any relation? Dan > Jim > -- > Jim McCusker > Programmer Analyst > Krauthammer Lab, Pathology Informatics > Yale School of Medicine > james.mccusker@yale.edu | (203) 785-6330 > http://krauthammerlab.med.yale.edu > > PhD Student > Tetherless World Constellation > Rensselaer Polytechnic Institute > mccusj@cs.rpi.edu > http://tw.rpi.edu >
Received on Monday, 18 April 2011 15:57:54 UTC