- From: Pat Hayes <phayes@ai.uwf.edu>
- Date: Fri, 16 Nov 2001 12:41:58 -0600
- To: Graham Klyne <Graham.Klyne@MIMEsweeper.com>
- Cc: w3c-rdfcore-wg@w3.org
>>[Patrick Stickler:] >>> >Honestly, I find that the S proposal bends (and breaks) just >>> >too many established intuitions and expectations about RDF >>> >semantics, >> >[Pat Hayes:] >> > I don't think it breaks the semantics at all; it just insists on a >>> rather rigorous way of understanding the meaning of literal labels. >>> That may ruffle many expectations, I concede. But part of our task >>> may be educational :-). > >If we were working on a "greenfield site" [*] I'd adopt the S scheme >straight away. It's simple and coherent and doesn't preclude >simplified use, as illustrated above.. But I still worry about >backward compatibility. ([*] UK planning (zoning) jargon for >building on virgin land; preferred by property developers because >it's cheaper than building on so-called "brownfield" sites.) > >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. > 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. > Any interpretation of the string as (say) an integer would be >outside the scope of RDF, but we could still have some inference >from the above like: > > ex:foo ex:integerProperty _:int10node . > _:int10node rdf:type xsdv:integer . > _:int10node rdf:value "10" . Yes, but that is more the DC style than the S style. Howrya gonna get the xsd: name into a property position?? 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 Friday, 16 November 2001 13:43:00 UTC