- From: Pat Hayes <phayes@ai.uwf.edu>
- Date: Tue, 20 Nov 2001 13:37:18 -0600
- To: Graham Klyne <Graham.Klyne@MIMEsweeper.com>
- Cc: w3c-rdfcore-wg@w3.org
>At 12:41 PM 11/16/01 -0600, Pat Hayes wrote: >>>I'd like to consider a simple example: >>> >>> ex:foo ex:property "10" . >>> ex:property rdfs:range xsd:integer . >>> >>>Can this be legitimate? >> >>In S, I don't think so, since xsd:integer has to be a property >>rather than a class. >> >>Even if we allow it to be used in both ways at once, I cannot see >>any way in which range information on the asserting property (ie >>the property that occurs in the triple which has the bNode as >>object in the S idiom) can possibly constrain the datatype used in >>the second triple (the one that has the bNode as subject and the >>literal as object.), or indeed even have any interaction with it. >>The triple >>_:x xsd:integer "10" . >>can be, at best, only constrained to be false by a class >>restriction of the form >>_:x rdf:type <someClass> . >>It cannot be forced to be true. > >I think I didn't state my query clearly enough. The above example >is exactly the case I wanted to test (because I think it corresponds >to some current usage). But I was not clear that the xsd:integer is >*not* intended to be the property used in the S scheme to indicate >an integer value. > >Consider this slightly enlarged example: > > ex:foo ex:property "10" . > ex:property rdfs:range xsd:integer . > ex:foo s:property _:a . > _:a s:inDecimal "10" . > >where it is the node labeled _:a that denotes the integer value 10. >(This entails the smaller example above, right?) > >I think it *can* be legimitate if the xsd:... URIs are considered to >be RDF class names whose value space is strings that conform to the >corresponding xsd:... lexical space. In this interpretation, the >xsd:... URIs would not be used to label properties; some other >label would be required for that (s:property and s:inDecimal in the >above example). OK, but than that is yet *another* suggestion, which we should maybe call G, which is somewhat like the DC suggestion. My problem with G is, what establishes the connection between the lexical class xsd:integer and the 'connecting' property s:inDecimal ? > >>> If so, what can we say about it? >>> >>>Could we, for example, allow rdf:type values like xsd:integer to >>>be subclasses of rdfs:literal, so that the members of the value >>>space are still just strings, but having a restricted lexical form? >> >>But that would not specify the datatype, since "10" might be a >>decimal or a binary or an octal or whatever. > >I agree that it wouldn't specify the datatype of the value denoted >by intermediate node (_:a in the example above, or _:int10node in >the example below). I don't see that as a problem. I do, since there is no way to specify that type, it seems. Since you are using xsd:integer to refer to the *lexical* space of the datatype, there is no name available for the value space; and, worse, the usual usage is that the datatype name refers to the value space rather than the lexical space, so this idiom doesn't conform to accepted usage either. (In haste) 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 Tuesday, 20 November 2001 14:36:47 UTC