- From: Brian McBride <bwm@hplb.hpl.hp.com>
- Date: Mon, 12 Nov 2001 19:33:19 +0000
- To: Pat Hayes <phayes@ai.uwf.edu>
- CC: w3c-rdfcore-wg@w3.org, "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
Great stuff Pat. Brought some much needed structure to the discussion. Pat Hayes wrote: [...] > Datatype names can be names of classes or names of properties, or both. Nervous twitch of antenae: Don't we have an issue about whether classes and properties are disjoint? Yes, in http://www.w3.org/2001/sw/RDFCore/20010801-f2f/2001-08-02.html#T21-00-44 we have restated rdfs-subClassOf-a-Property as "are Property and Class disjoint?" If we decide they are disjoint, does that cause P++ any problems? [...] > > None of the first three proposals require all this elaboration (although > they are not incompatible with it), since they all assume that literal > meanings are completely specified by the literal label (to be a single > literal value in X, or to be a string in S and DC), and the datatype > class heirarchy, if it exists, is invisible to RDFS. Is that true, which I suppose means "what exactly do you mean by that?" For example, in proposal S, if I define the domain of say xsd:integer to be foo:integer and rdfs can conclude that any bNode with an xsd:integer property hanging of it is an integer. Similarly, in the S proposal, would not xsd:byte be a subProperty of xsd:short which is a subProperty of ... > They can all be > straightforwardly handled in RDF/XML. > > > The S and CD proposals require that users conform to a given 'idiom', > and are often incompatible with current common usage in which literals > are used to refer to things other than strings; I know what you mean here, but I object to the term incompatible. Current RDF does not do anything about datatypes. In one interpretation all literals denote strings, and if I have a property with value "10", then that's just fine. An application can 'know' that it should interpret that as an integer. With for example, the X and S and DC proposals they can continue to do so. The datatype information is simply not represented in the RDF model; its encoded in the definition of the property. This doesn't seem to me to any different from, say the property weightInKg which takes a P++ representation of an integer implying that units are kilograms, not pounds. [...] > Hope this helps; anyway, I've done a dump of *my* mental state, thank > goodness. Thanks Pat. This was really useful. Brian
Received on Monday, 12 November 2001 14:33:12 UTC