- From: Pat Hayes <phayes@ai.uwf.edu>
- Date: Wed, 7 Nov 2001 14:53:34 -0600
- To: Patrick.Stickler@nokia.com
- Cc: w3c-rdfcore-wg@w3.org
> > -----Original Message----- >> From: ext Pat Hayes [mailto:phayes@ai.uwf.edu] >> Sent: 06 November, 2001 20:17 >> To: Stickler Patrick (NRC/Tampere) >> Cc: w3c-rdfcore-wg@w3.org >> Subject: Re: ACTION 2001-11-02#02: Datatyping use-cases from CC/PP >> >> >> >...... >> >It appears to me that we have two separate issues here: >> > >> >1. The association of data type to literal. >> >2. The prescriptive/descriptive nature of data types. >> >> Can you enlarge on that second point? I have no idea what you mean, >> and it doesn't seem to have come up before. >> >> For what its worth, I have always assumed that RDF is basically a >> descriptive language, so if 'prescriptive' is somehow in contrast to >> descriptive then I might take umbrage. >> >> Pat > >There was discussion about this a few weeks ago in the >rdf-interest list (or was it rdf-logic...?) > >Anyway, the gist is that if both a local type and a range >are defined, then the range can be seen as prescriptive such >that a value can be deemed invalid if the local type is >not equivalent to or a subclass of the range type. Thanks, but I still don't know what you are talking about. What does it mean to say that a value is 'invalid'? The way I see RDF is that triples make assertions. More triples make more assertions, which restrict the set of satisfying interpretations. There is no notion of some part of a triple being 'invalid': if you can write it down, then it ought to mean something. (If some construction is meaningless then we should rule it out as syntactically illegal; but there is a strong RDF cultural bias against this kind of restriction, for methodological reasons having to do with the 'open-ness' of the semantic web. ) >If no local type is defined for the value, then the range >can be seen as descriptive of the type of the value. > >The latter is all fine and good, until we think about lexical >forms and the fact that lexical forms are specific to a >given data type, and thus, the descriptive approach is not >reliable as it may suggest an interpretation for which the >lexical form is either not valid or "unknown". Well, it can be unknown: that is harmless. I agree that we need some security against *incorrect* interpretations being used on literals, so they are interpreted in ways that are not the way intended. Pat -- --------------------------------------------------------------------- IHMC (850)434 8903 home 40 South Alcaniz St. (850)202 4416 office Pensacola, FL 32501 (850)202 4440 fax phayes@ai.uwf.edu http://www.coginst.uwf.edu/~phayes
Received on Wednesday, 7 November 2001 15:53:34 UTC