- From: Charles McCathieNevile <charles@w3.org>
- Date: Sat, 7 Feb 2004 08:14:47 -0500 (EST)
- To: "Cayzer, Steve" <Steve.Cayzer@hp.com>
- Cc: "'Miles, AJ (Alistair) '" <A.J.Miles@rl.ac.uk>, "'public-esw-thes@w3.org'" <public-esw-thes@w3.org>
I don't see why something as well as a URI is necessary. The idea of the semantic web is that URIs are identifiers, good for identifying "things". There are some things they are good at identifying. One is actual pages on the web, since these already have a URI. But there are also "concepts" - things that have a way of identifying them, and various descriptions. We can give them a name (URI) or we can just describe them (as blank nodes). And I think it's a bad idea to insist on a single preferred label. Words are what people use becausee we don't have blank nodes. They aren't equivalent to URIs, because we already know that they are duplicated, ambiguous, overloaded. But we're stuck with them as identifiers, since we can't look up URIs in our head. (We also have descriptions, and we end up using a mixture of the two to try and disambiguate concepts). If two concepts have the same labels and descritptions, they might be the same. It's certainly a useful working assumption. But a few long philosophical discussions are enough to realise that often you can spend hours talking about something before realising that each person is talking a bout a different thing - and then you disambiguate it by adding some qualifying information that is unique to one of the options. So we can use identical graphs for two blank concept nodes to assert that they are the same, for a given purpose. Or we can use a URI. In either case, we have the important ability to go further, and subclass the concept perhaps in two or more ways. Cheers Chaals On Fri, 6 Feb 2004, Cayzer, Steve wrote: >I think Al's point is that we need *some* way to uniquely identify concepts >other than by URI (ie by description) [Al - correct me if I'm wrong!] > >One way is to insist on only one prefLabel per thesaurus. >It sounds like you think this is an unreasonable constraint (which might be >true). So if that's the case, what property/ies should we use? Is there a >concept equivalent of foaf:mbox ? > > >> -----Original Message----- >> From: Charles McCathieNevile [mailto:charles@w3.org] >> Sent: 06 February 2004 09:14 >> To: Cayzer, Steve >> Cc: 'Miles, AJ (Alistair) '; 'public-esw-thes@w3.org' >> Subject: RE: Blank nodes for concepts. >> >> >> >> On Fri, 6 Feb 2004, Cayzer, Steve wrote: >> >> > >> >That's my reading of (b) >> > >> >b. A combination of the concept's prefLabel and the URI of the >> >thesaurus to which it belongs. >> > >> >> to expand on my example >> >> <Concept> >> <prefLabel>Bar</prefLabel> >> <altLabel>Baz</altLabel> >> <rdf:isDefinedBy >> rdf:resource="http://example.com/concepts?easyToFind"/> >> </Concept> >> <Concept> >> <prefLabel>Bar</prefLabel> >> <altLabel>Foo</altLabel> >> <rdf:isDefinedBy >> rdf:resource="http://example.com/concepts?worksForPWD"/> >> </Concept> >> >> seems reasonable, or am I missing something? >> >> Hmm. I am assuming you point to the term definition, not just >> the thesaurus it is in. But I think even if I pointed to the >> latter (i.e. the thesaurus defines a concept with two >> prefLabels) there would be nothing to stop the thesaurus from >> defining two concepts with the same prefLabel and different >> alternative labels. And I don't see there is anything wrong >> with deciding to name a concept definition: >> >> <Concept rdf:about="#foo"> >> <prefLabel>Bar</prefLabel> >> <altLabel>Foo</altLabel> >> <rdf:isDefinedBy >> rdf:resource="http://example.com/concepts?worksForPWD"/> >> </Concept> >> >> it just gives you a way to refer to this definition. ? >> >> cheers >> >> chaals >> >> >> -----Original Message----- >> >> From: Charles McCathieNevile [mailto:charles@w3.org] >> >> Sent: 06 February 2004 01:05 >> >> >> >> doesn't give you any right to infer that the two balnk >> nodes are the >> >> same (this would be that case if you made prefLabel map 1:1 with >> >> concepts but I think that's a bad idea anyway). >> >> >> >> Looking at user scenarios, there is an obvious cost to two >> concepts >> >> having the same preferred label - whenever you want to classify >> >> something by that label you need to be clear which one you >> mean. On >> >> the benefit side, you might well have a term that commonly >> refers to >> >> a couple of different concepts, and want to be easily able to look >> >> for things with the preferred Label. >> >> >> >> "accessible" is the example that springs to mind in my everyday >> >> stuff. I suspect in putting vocbularies together it's also useful. >> >> >> >> Cheers >> >> >> >> Chaals >> >> >> >> On Thu, 5 Feb 2004, Steve Cayzer wrote: >> >> >> >> > >> >> >Makes sense to me. >> >> > >> >> >Might be worth adding an explanation to one of the docos, both >> >> >technical (as >> >> >below) and non technical (implication - you can't add a new >> >> concept with the >> >> >same prefLabel as another concept in the same thesaurus) >> >> > >> > Charles McCathieNevile http://www.w3.org/People/Charles tel: +61 409 134 136 SWAD-E http://www.w3.org/2001/sw/Europe fax(france): +33 4 92 38 78 22 Post: 21 Mitchell street, FOOTSCRAY Vic 3011, Australia or W3C, 2004 Route des Lucioles, 06902 Sophia Antipolis Cedex, France
Received on Saturday, 7 February 2004 08:15:00 UTC