- From: Joshua Tauberer <jt@occams.info>
- Date: Mon, 18 Dec 2006 18:33:54 -0500
- To: John Black <JohnBlack@kashori.com>
- CC: semantic-web@w3.org
John Black wrote: >> <> indexicals:isBeingReadBy _:you . >> <> indexicals:isBeingReadAtLocation _:here . >> (then you go on to make assertions about _:you and _:here.) >> >> where <> is the URI for the document itself, > > I think it is ironic that your example of how to avoid the need for > indexicals uses the one indexical URI that RDF can't seem to do without, > that is: <>. or rdf:about="". Don't oblivious applications use this > indexical? Ah, but it's not indexical (in the relevant sense). See, that's what we get for having syntactic shortcuts and long specs. <> and rdf:about="" are both necessarily interpreted as relative URIs, relative to the base URI of the document being parsed. Since they're blank, they are evaluated as the base URI itself. Provided the parser knows the URI of the document it is loading, it sees those as the URI of the document. (This is the same mechanism behind rdf:about="#abc".) The reason this is OK is that this behavior is mandated in the RDF/XML specification, so no application that conforms to the spec can be oblivious to that. But, actually, the use of <> in my example was a bit arbitrary. I could have also written _:you rdf:type indexicals:TheReadingAgent . (or any number of other things). -- - Josh Tauberer http://razor.occams.info "Yields falsehood when preceded by its quotation! Yields falsehood when preceded by its quotation!" Achilles to Tortoise (in "Gödel, Escher, Bach" by Douglas Hofstadter)
Received on Monday, 18 December 2006 23:34:07 UTC