- From: Patrick Stickler <patrick.stickler@nokia.com>
- Date: Tue, 05 Feb 2002 17:44:16 +0200
- To: RDF Core <w3c-rdfcore-wg@w3.org>
In case anyone missed it, and in case anyone finds it useful. Patrick -- Patrick Stickler Phone: +358 50 483 9453 Senior Research Scientist Fax: +358 7180 35409 Nokia Research Center Email: patrick.stickler@nokia.com ------ Forwarded Message From: "ext Peter F. Patel-Schneider" <pfps@research.bell-labs.com> Date: Tue, 05 Feb 2002 10:32:19 -0500 To: patrick.stickler@nokia.com Cc: www-rdf-logic@w3.org Subject: Re: RDFCore WG: Datatyping documents From: Patrick Stickler <patrick.stickler@nokia.com> Subject: Re: RDFCore WG: Datatyping documents Date: Mon, 04 Feb 2002 23:19:27 +0200 [...] > > Right now the document says that the meaning of > > Unicode nodes are pairs consisting of Unicode strings and data values. > > Without quick, clear, and forceful statements to the contrary, TDL will be > > inextricably associated with this meaning,. > > Fair enough. > > Perhaps you would like to offer the underpinnings of an MT that > you feel more precisely captures the fundamental intent of the > TDL pairing model. It would be welcome, I'm sure. I believe that all of the proposals that I have floated have this intent. The various proposals have differing details, based on how they deal with the issues raised by things like XML Schema union datatypes and xsi:type attributes. [...] > Cheers, > > Patrick The following is taken from one of my proposals for a Web Ontology Language. A datatyping scheme is a collection of datatypes, DT. For each datatype d in DT there are four components: U(d), URI for the datatype; L(d), the lexical space for the datatype; V(d), the value space for the datatype; and LV(d) : L(d) -> V(d), the lexical-to-value mapping for the datatype. Given a datatyping scheme, let L = union over d in DT of L(d), lexical values V = union over d in DT of V(d), data values LV = union over d in DT of LV(d) An [...] interpretation, I, over a datatyping scheme DT [consists] of R, nonempty the domain of resources [...] P <= R, nonempty properties C <= R, nonempty classes EXT : P -> 2^(Rx(RuV)) property extensions CEXT : C -> 2^(RuV) class extensions S : N -> R mapping from names to denotation D1 DT <= C D2 S(Ud) = d for d in DT D3 S(swol:Datatype) in C\DT D4 CEXT(S(swol:Datatype)) = DT D5 for d in DT CEXT(d) = Vd [The interpretation of a literal node with label TEXT is constrained to be an element of LV(text).] Now this does have some problems with datatyping schemes that have ``rogue'' datatypes that cause LV to be too loose. These problems can be alleviated by taking XML Schema local or schema typing information from XML documents, and using that to uniquely determine the datatype mapping (much in the way that Pat is suggesting with dtype). The important thing to note here is that the denotation of a literal node is in the value space of a datatype. peter ------ End of Forwarded Message
Received on Tuesday, 5 February 2002 10:49:33 UTC