- From: Pat Hayes <phayes@ihmc.us>
- Date: Fri, 18 Nov 2011 10:35:05 -0600
- To: Dan Brickley <danbri@danbri.org>
- Cc: RDF Working Group WG <public-rdf-wg@w3.org>
On Nov 9, 2011, at 3:11 PM, Dan Brickley wrote: > On 9 November 2011 21:53, RDF Working Group Issue Tracker > <sysbot+tracker@w3.org> wrote: >> RDF-ISSUE-79 (undefined-datatype): What is the value of a literal whose datatype IRI is not a datatype? [RDF Concepts] >> >> http://www.w3.org/2011/rdf-wg/track/issues/79 >> >> Raised by: Richard Cyganiak >> On product: RDF Concepts >> >> The RDF Concepts spec (in both 2004 and 1.1 versions) does not answer the question what's the value of a literal where the datatype IRI doesn't actually denote a datatype, like <"foo",http://example.com/not-a-datatype>. This is surprising, as there is a section that normatively defines the value of *all other* literals. >> >> There are many possibilities: >> >> (i) the spec leaves it undefined >> (ii) that's not a valid RDF graph >> (iii) it's a valid RDF graph, but the value, if any, is unknown >> (iv) it's a valid RDF graph, and the literal is ill-typed >> >> This should be made explicit. >> >> The status quo is (i). I believe that the model theory says it's (iii). > > -1 on (ii) > I don't like the notion that a single illformed triple could in some > sense "invalidate" a graph. There's a weaker sense in which the whole > graph, considered as a description, is no longer going to be a true > description in any interestingly relevant world. But "invalid" sounds > harsher than that. Um.. in the semantics document, "invalid" means exactly that, ie false in all interpretations. What it sounds harsher than is surely irrelevant. > > Note that even mentioning such a construct with RDF'99's reification > vocabulary would (if (ii) were our rule) make the graph invalid. Which > probably just goes to show that reification still isn't quoting. > > I'm ok with (i) (iii) or (iv). Whatever we do or say we'll have lots > of crap data and it'll get often get scrubbed somehow rather than > rejected absolutely. XML-style 'catch fire and burn' strictness > probably wouldn't serve us well here. > > BTW how do we know a URI isn't a datatype? Any URI might be the name of a datatype. The entailment regime you are working under when you make inferences is what decides whether it is being treated as one or not. Pat > What about punning? e.g. it > might be a datatype proposal... > > Dan > > ------------------------------------------------------------ IHMC (850)434 8903 or (650)494 3973 40 South Alcaniz St. (850)202 4416 office Pensacola (850)202 4440 fax FL 32502 (850)291 0667 mobile phayesAT-SIGNihmc.us http://www.ihmc.us/users/phayes
Received on Friday, 18 November 2011 16:35:41 UTC