David, hello. On 2010 Nov 6, at 20:42, David Booth wrote:
>>>> httpRange-14 requires that a URI with a 200 response MUST be an IR; > ^^^^^^^ > Not quite. The httpRange-14 decision says that the resource *is* an IR: > http://lists.w3.org/Archives/Public/www-tag/2005Jun/0039 Yes, when I phrased this, I did indeed mean it as an analytic-must rather than an rfc2119-synthetic-must (this is the distinction you're making, yes?) >>>> a URI with a 303 MAY be a NIR. >>>> >>>> Ian is (effectively) suggesting that a URI with a 200 response MAY >>>> be an IR, in the sense that it is defeasibly taken to be an IR, >>>> unless this is contradicted by a self-referring statement within >>>> the RDF obtained from the URI. > > To be clear, Ian's toucan URI *does* identify an information resource, > whether or not it *also* identifies a toucan: Indeed, because the decision defines what an IR is, so that Ian's toucan is necessarily an IR in the sense in which that term is currently defined. > Thus, Ian has created an ambiguity by returning a 200 response. (Ian can of course speak for himself, but...) I take it that Ian is suggesting resolving the ambiguity he has created, and thus the need for any heuristics, by extending the notion of IR in such a way that a URI with a 200 response *is* an IR, *unless* dereferencing it returns RDF which (authoritatively) declares that the URI is a NIR. > However, for those applications that need to distinguish between > the toucan and its web page, Ian is effectively suggesting the > *heuristic* that if the content served in the 200 response says that the > URI identifies a toucan, then the app should ignore the fact that the > URI also identifies a web page, and treat the URI as though it *only* > identifies the toucan. The suggestion does mean that the toucan URI, since it now identifies a toucan, cannot also identify the toucan's webpage, which is therefore unnamed. I don't know if that's a problem or not (maybe it is, if you want to be able to say "I got this information about the toucan called </toucan> from <X>"). If it's a problem, then perhaps the </toucan> URI could point towards a </toucan.rdf> URI which contains the same RDF as </toucan>, but which is still an IR. Then </toucan.rdf> is the toucan's webpage. Best wishes, Norman -- Norman Gray : http://nxg.me.uk
