- From: Graham Klyne <graham.klyne@zoo.ox.ac.uk>
- Date: Thu, 10 Nov 2011 14:25:12 +0000
- To: Paul Groth <p.t.groth@vu.nl>
- CC: Luc Moreau <L.Moreau@ecs.soton.ac.uk>, Stephan Zednik <zednis@rpi.edu>, Provenance Working Group WG <public-prov-wg@w3.org>
On 06/11/2011 19:04, Paul Groth wrote: > This is where the confusion is. Literals in RDF-speak are not URIs. Maybe a note in either prov-o or prov-dm would help clarify this. Yes. Referring to the model theoretic style of semantics used for RDF (and also for formalizing first order logic - if DM is appealing to some different semantic framework, this needs to be spelled out): Specifically literals have a fixed denotation. A plain string denotes itself. In integer literal denotes the number determined according to the numeric encoding scheme, a URI literal denotes a URI (*), etc... By contrast, names (i.e. URIs in RDF) denote whatever some "interpretation" says they denote. This interpretation is just a function from names to things, which is not fixed by the language. The associated semantics (inherent and/or additionally defined) constrain the interpretations that are considered valid (also known as "models"). What this all means is that if something is a literal, you can't arbitrary say it denotes the American president known as "Barack Obama" (unless such a mapping is baked into an underlying literal structure, which doesn't really make sense). Where this all leads is that I think the roles in DM should be names, not literals. #g -- (*) ... as opposed to a URI-node in RDF, which denotes whatever the applicable interpretation says it denotes.
Received on Thursday, 10 November 2011 16:16:58 UTC